1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> 2<html><head> 3<meta http-equiv="content-type" content="text/html; charset=ISO-8859-1"> 4 5 6<title>C++ Standard Library Active Issues List</title> 7<style type="text/css"> 8p {text-align:justify} 9li {text-align:justify} 10blockquote.note 11{ 12 background-color:#E0E0E0; 13 padding-left: 15px; 14 padding-right: 15px; 15 padding-top: 1px; 16 padding-bottom: 1px; 17} 18ins {background-color:#A0FFA0} 19del {background-color:#FFA0A0} 20</style> 21</head><body> 22<table> 23<tbody><tr> 24<td align="left">Doc. no.</td> 25<td align="left">N3011=09-0201</td> 26</tr> 27<tr> 28<td align="left">Date:</td> 29<td align="left">2009-11-08</td> 30</tr> 31<tr> 32<td align="left">Project:</td> 33<td align="left">Programming Language C++</td> 34</tr> 35<tr> 36<td align="left">Reply to:</td> 37<td align="left">Howard Hinnant <<a href="mailto:howard.hinnant@gmail.com">howard.hinnant@gmail.com</a>></td> 38</tr> 39</tbody></table> 40<h1>C++ Standard Library Active Issues List (Revision R68)</h1> 41 42 <p>Reference ISO/IEC IS 14882:2003(E)</p> 43 <p>Also see:</p> 44 <ul> 45 <li><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-toc.html">Table of Contents</a> for all library issues.</li> 46 <li><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html">Index by Section</a> for all library issues.</li> 47 <li><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html">Index by Status</a> for all library issues.</li> 48 <li><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html">Library Defect Reports List</a></li> 49 <li><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html">Library Closed Issues List</a></li> 50 </ul> 51 <p>The purpose of this document is to record the status of issues 52 which have come before the Library Working Group (LWG) of the ANSI 53 (J16) and ISO (WG21) C++ Standards Committee. Issues represent 54 potential defects in the ISO/IEC IS 14882:2003(E) document. 55 </p> 56 57 <p>This document contains only library issues which are actively being 58 considered by the Library Working Group, i.e., issues which have a 59 status of <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a>, 60 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a>, or <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Review">Review</a>. See 61 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html">Library Defect Reports List</a> for issues considered defects and 62 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html">Library Closed Issues List</a> for issues considered closed.</p> 63 64 <p>The issues in these lists are not necessarily formal ISO Defect 65 Reports (DR's). While some issues will eventually be elevated to 66 official Defect Report status, other issues will be disposed of in 67 other ways. See <a href="#Status">Issue Status</a>.</p> 68 69 <p>Prior to Revision 14, library issues lists existed in two slightly 70 different versions; a Committee Version and a Public 71 Version. Beginning with Revision 14 the two versions were combined 72 into a single version.</p> 73 74 <p>This document includes <i>[bracketed italicized notes]</i> as a 75 reminder to the LWG of current progress on issues. Such notes are 76 strictly unofficial and should be read with caution as they may be 77 incomplete or incorrect. Be aware that LWG support for a particular 78 resolution can quickly change if new viewpoints or killer examples are 79 presented in subsequent discussions.</p> 80 81 <p>For the most current official version of this document see 82 <a href="http://www.open-std.org/jtc1/sc22/wg21/">http://www.open-std.org/jtc1/sc22/wg21/</a>. 83 Requests for further information about this document should include 84 the document number above, reference ISO/IEC 14882:2003(E), and be 85 submitted to Information Technology Industry Council (ITI), 1250 Eye 86 Street NW, Washington, DC 20005.</p> 87 88 <p>Public information as to how to obtain a copy of the C++ Standard, 89 join the standards committee, submit an issue, or comment on an issue 90 can be found in the comp.std.c++ FAQ. 91 </p> 92 93<p><a name="submit_issue"></a><b>How to submit an issue</b></p> 94 95<ol type="A"> 96<a name="submit_issue_A"></a><li> 97Mail your issue to the author of this list. 98</li> 99<a name="submit_issue_B"></a><li> 100Specify a short descriptive title. If you fail to do so, the subject line of your 101mail will be used as the issue title. 102</li> 103<a name="submit_issue_C"></a><li> 104If the "From" on your email is not the name you wish to appear as issue submitter, 105then specify issue submitter. 106</li> 107<a name="submit_issue_D"></a><li> 108Provide a brief discussion of the problem you wish to correct. Refer to the latest 109working draft or standard using [section.tag] and paragraph numbers where appropriate. 110</li> 111<a name="submit_issue_E"></a><li> 112Provide proposed wording. This should indicate exactly how you want the standard 113to be changed. General solution statements belong in the discussion area. This 114area contains very clear and specific directions on how to modify the current 115draft. If you are not sure how to word a solution, you may omit this part. 116But your chances of a successful issue greatly increase if you attempt wording. 117</li> 118<a name="submit_issue_F"></a><li> 119It is not necessary for you to use html markup. However, if you want to, you can 120<ins><ins>insert text like this</ins></ins> and <del><del>delete text like 121this</del></del>. The only strict requirement is to communicate clearly to 122the list maintainer exactly how you want your issue to look. 123</li> 124<a name="submit_issue_G"></a><li> 125It is not necessary for you to specify other html font/formatting 126mark-up, but if you do the list maintainer will attempt to respect your 127formatting wishes (as described by html markup, or other common idioms). 128</li> 129<a name="submit_issue_H"></a><li> 130It is not necessary for you to specify open date or last modified date (the date 131of your mail will be used). 132</li> 133<a name="submit_issue_I"></a><li> 134It is not necessary for you to cross reference other issues, but you can if you 135like. You do not need to form the hyperlinks when you do, the list maintainer will 136take care of that. 137</li> 138<a name="submit_issue_J"></a><li> 139One issue per email is best. 140</li> 141<a name="submit_issue_K"></a><li> 142Between the time you submit the issue, and the next mailing deadline 143(date at the top of the Revision History), you <em>own</em> this issue. 144You control the content, the stuff that is right, the stuff that is 145wrong, the format, the misspellings, etc. You can even make the issue 146disappear if you want. Just let the list maintainer know how you want 147it to look, and he will try his best to accommodate you. After the 148issue appears in an official mailing, you no longer enjoy exclusive 149ownership of it. 150</li> 151</ol> 152 153 154<h2>Revision History</h2> 155<ul> 156<li>R68: 1572009-11-06 post-Santa Cruz mailing. 158<ul> 159<li><b>Summary:</b><ul> 160<li>205 open issues, down by 77.</li> 161<li>1055 closed issues, up by 120.</li> 162<li>1260 issues total, up by 43.</li> 163</ul></li> 164<li><b>Details:</b><ul> 165<li>Added the following Dup issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1230">1230</a>.</li> 166<li>Added the following NAD issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1229">1229</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1236">1236</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1243">1243</a>.</li> 167<li>Added the following NAD Editorial issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1232">1232</a>.</li> 168<li>Added the following NAD Future issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1235">1235</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1242">1242</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1248">1248</a>.</li> 169<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1218">1218</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1219">1219</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1221">1221</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1222">1222</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1223">1223</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1224">1224</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1225">1225</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1234">1234</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1240">1240</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1244">1244</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1245">1245</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1246">1246</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1249">1249</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1250">1250</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1251">1251</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1252">1252</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1253">1253</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1254">1254</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1255">1255</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1256">1256</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1257">1257</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1258">1258</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1259">1259</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1260">1260</a>.</li> 170<li>Added the following Open issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1228">1228</a>.</li> 171<li>Added the following Ready issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1227">1227</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1237">1237</a>.</li> 172<li>Added the following Review issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1247">1247</a>.</li> 173<li>Added the following Tentatively NAD Editorial issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1233">1233</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1239">1239</a>.</li> 174<li>Added the following Tentatively NAD Future issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1238">1238</a>.</li> 175<li>Added the following Tentatively Ready issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1220">1220</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1226">1226</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1231">1231</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1241">1241</a>.</li> 176<li>Changed the following issues from New to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1132">1132</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1148">1148</a>.</li> 177<li>Changed the following issues from Open to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#96">96</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#458">458</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#463">463</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#916">916</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#917">917</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#919">919</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#955">955</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#977">977</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1009">1009</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1020">1020</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1035">1035</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1042">1042</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1051">1051</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1064">1064</a>.</li> 178<li>Changed the following issues from Review to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#668">668</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#930">930</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1091">1091</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1102">1102</a>.</li> 179<li>Changed the following issues from Tentatively NAD to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#588">588</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#617">617</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#971">971</a>.</li> 180<li>Changed the following issues from Tentatively NAD Future to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1062">1062</a>.</li> 181<li>Changed the following issues from NAD Concepts to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1143">1143</a>.</li> 182<li>Changed the following issues from New to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1116">1116</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1117">1117</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1122">1122</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1129">1129</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1145">1145</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1146">1146</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1147">1147</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1155">1155</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1166">1166</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1172">1172</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1174">1174</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1179">1179</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1195">1195</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1196">1196</a>.</li> 183<li>Changed the following issues from Open to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#431">431</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#580">580</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#635">635</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#719">719</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#823">823</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#827">827</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#879">879</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#880">880</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#908">908</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#923">923</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#924">924</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#926">926</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#944">944</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#947">947</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#958">958</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1046">1046</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1048">1048</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1054">1054</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1055">1055</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1075">1075</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1088">1088</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1160">1160</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1161">1161</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1162">1162</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1163">1163</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1165">1165</a>.</li> 184<li>Changed the following issues from Review to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#828">828</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#897">897</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#976">976</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1043">1043</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1047">1047</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1049">1049</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1050">1050</a>.</li> 185<li>Changed the following issues from New to NAD Future: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1120">1120</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1150">1150</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1184">1184</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1203">1203</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1217">1217</a>.</li> 186<li>Changed the following issues from Open to NAD Future: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#484">484</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#532">532</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#851">851</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#933">933</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#935">935</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#936">936</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#961">961</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1041">1041</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1053">1053</a>.</li> 187<li>Changed the following issues from Tentatively NAD Future to NAD Future: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1031">1031</a>.</li> 188<li>Changed the following issues from New to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1118">1118</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1119">1119</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1151">1151</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1153">1153</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1156">1156</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1171">1171</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1173">1173</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1183">1183</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1191">1191</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1211">1211</a>.</li> 189<li>Changed the following issues from Ready to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#430">430</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#834">834</a>.</li> 190<li>Changed the following issues from Review to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#397">397</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#408">408</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#835">835</a>.</li> 191<li>Changed the following issues from Tentatively NAD to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#625">625</a>.</li> 192<li>Changed the following issues from New to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1123">1123</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1134">1134</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1135">1135</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1136">1136</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1144">1144</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1177">1177</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1194">1194</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1204">1204</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1216">1216</a>.</li> 193<li>Changed the following issues from Open to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#296">296</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#471">471</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#485">485</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#539">539</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#816">816</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#860">860</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#865">865</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#872">872</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#920">920</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#932">932</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#939">939</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#940">940</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#960">960</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#963">963</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#974">974</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#978">978</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1011">1011</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1030">1030</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1079">1079</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1098">1098</a>.</li> 194<li>Changed the following issues from Review to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#473">473</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#671">671</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#836">836</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#854">854</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#868">868</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#871">871</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#889">889</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#893">893</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#921">921</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#950">950</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#954">954</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#957">957</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#962">962</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#967">967</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#968">968</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#983">983</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1052">1052</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1094">1094</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1095">1095</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1097">1097</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1100">1100</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1104">1104</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1157">1157</a>.</li> 195<li>Changed the following issues from New to Review: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1130">1130</a>.</li> 196<li>Changed the following issues from Open to Review: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#556">556</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#631">631</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#676">676</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#727">727</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#929">929</a>.</li> 197<li>Changed the following issues from Open to Tentatively NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1056">1056</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1099">1099</a>.</li> 198<li>Changed the following issues from New to Tentatively NAD Concepts: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1186">1186</a>.</li> 199<li>Changed the following issues from New to Tentatively NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1115">1115</a>.</li> 200<li>Changed the following issues from New to Tentatively NAD Future: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1121">1121</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1201">1201</a>.</li> 201<li>Changed the following issues from Open to Tentatively NAD Future: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1112">1112</a>.</li> 202<li>Changed the following issues from New to Tentatively Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1126">1126</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1138">1138</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1152">1152</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1158">1158</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1189">1189</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1192">1192</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1208">1208</a>.</li> 203<li>Changed the following issues from Open to Tentatively Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#987">987</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#999">999</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1071">1071</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1090">1090</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1108">1108</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1113">1113</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1114">1114</a>.</li> 204<li>Changed the following issues from Ready to WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#149">149</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#419">419</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#498">498</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#564">564</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#565">565</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#630">630</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#659">659</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#696">696</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#711">711</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#716">716</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#723">723</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#788">788</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#822">822</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#838">838</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#847">847</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#857">857</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#859">859</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#876">876</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#881">881</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#883">883</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#886">886</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#934">934</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1004">1004</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1178">1178</a>.</li> 205<li>Changed the following issues from Tentatively Ready to WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1012">1012</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1019">1019</a>.</li> 206</ul></li> 207</ul> 208</li> 209<li>R67: 2102009-09-25 pre-Santa Cruz mailing. 211<ul> 212<li><b>Summary:</b><ul> 213<li>282 open issues, up by 32.</li> 214<li>935 closed issues, down by 1.</li> 215<li>1217 issues total, up by 31.</li> 216</ul></li> 217<li><b>Details:</b><ul> 218<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1187">1187</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1188">1188</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1189">1189</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1190">1190</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1191">1191</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1192">1192</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1193">1193</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1194">1194</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1195">1195</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1196">1196</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1197">1197</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1198">1198</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1199">1199</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1200">1200</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1201">1201</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1202">1202</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1203">1203</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1204">1204</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1205">1205</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1206">1206</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1207">1207</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1208">1208</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1209">1209</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1210">1210</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1211">1211</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1212">1212</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1213">1213</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1214">1214</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1215">1215</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1216">1216</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1217">1217</a>.</li> 219<li>Changed the following issues from NAD to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#296">296</a>.</li> 220<li>Changed the following issues from WP to Pending WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#970">970</a>.</li> 221<li>Changed the following issues from Open to Review: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#976">976</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1052">1052</a>.</li> 222<li>Changed the following issues from Ready to Review: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#780">780</a>.</li> 223</ul></li> 224</ul> 225</li> 226<li>R66: 2272009-07-31 post-Frankfurt mailing. 228<ul> 229<li><b>Summary:</b><ul> 230<li>250 open issues, down by 128.</li> 231<li>936 closed issues, up by 171.</li> 232<li>1186 issues total, up by 43.</li> 233</ul></li> 234<li><b>Details:</b><ul> 235<li>Added the following NAD issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1164">1164</a>.</li> 236<li>Added the following NAD Concepts issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1149">1149</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1167">1167</a>.</li> 237<li>Added the following NAD Editorial issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1168">1168</a>.</li> 238<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1144">1144</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1145">1145</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1146">1146</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1147">1147</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1148">1148</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1150">1150</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1151">1151</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1152">1152</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1153">1153</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1154">1154</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1155">1155</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1156">1156</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1158">1158</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1159">1159</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1166">1166</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1169">1169</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1170">1170</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1171">1171</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1172">1172</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1173">1173</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1174">1174</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1175">1175</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1176">1176</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1177">1177</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1179">1179</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1180">1180</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1181">1181</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1182">1182</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1183">1183</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1184">1184</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1185">1185</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1186">1186</a>.</li> 239<li>Added the following Open issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1160">1160</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1161">1161</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1162">1162</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1163">1163</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1165">1165</a>.</li> 240<li>Added the following Ready issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1178">1178</a>.</li> 241<li>Added the following Review issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1157">1157</a>.</li> 242<li>Changed the following issues from Open to Dup: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#750">750</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#895">895</a>.</li> 243<li>Changed the following issues from Open to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#111">111</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#128">128</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#138">138</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#190">190</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#219">219</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#290">290</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#309">309</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#342">342</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#343">343</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#382">382</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#394">394</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#398">398</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#417">417</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#418">418</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#421">421</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#459">459</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#466">466</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#492">492</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#502">502</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#503">503</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#546">546</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#573">573</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#582">582</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#585">585</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#597">597</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#606">606</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#614">614</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#632">632</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#721">721</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#747">747</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#751">751</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#833">833</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#941">941</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#992">992</a>.</li> 244<li>Changed the following issues from Review to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1003">1003</a>.</li> 245<li>Changed the following issues from Tentatively NAD to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#568">568</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#644">644</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#667">667</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#669">669</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#701">701</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#702">702</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#785">785</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#863">863</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#901">901</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#903">903</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#946">946</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#988">988</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#995">995</a>.</li> 246<li>Changed the following issues from Tentatively Ready to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1002">1002</a>.</li> 247<li>Changed the following issues from New to NAD Concepts: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1124">1124</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1127">1127</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1128">1128</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1139">1139</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1140">1140</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1141">1141</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1142">1142</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1143">1143</a>.</li> 248<li>Changed the following issues from Open to NAD Concepts: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#902">902</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#989">989</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1000">1000</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1007">1007</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1010">1010</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1015">1015</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1016">1016</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1017">1017</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1018">1018</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1026">1026</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1027">1027</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1028">1028</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1029">1029</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1032">1032</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1036">1036</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1057">1057</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1059">1059</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1072">1072</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1078">1078</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1081">1081</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1082">1082</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1083">1083</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1084">1084</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1085">1085</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1086">1086</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1092">1092</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1096">1096</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1105">1105</a>.</li> 249<li>Changed the following issues from Review to NAD Concepts: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1001">1001</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1005">1005</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1080">1080</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1087">1087</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1111">1111</a>.</li> 250<li>Changed the following issues from Tentatively NAD to NAD Concepts: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#912">912</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#918">918</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1074">1074</a>.</li> 251<li>Changed the following issues from Tentatively NAD Editorial to NAD Concepts: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#927">927</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1109">1109</a>.</li> 252<li>Changed the following issues from Tentatively Ready to NAD Concepts: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#906">906</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#913">913</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#914">914</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#928">928</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1024">1024</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1063">1063</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1067">1067</a>.</li> 253<li>Changed the following issues from Open to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#718">718</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#873">873</a>.</li> 254<li>Changed the following issues from Tentatively NAD Editorial to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#424">424</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#825">825</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#830">830</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#837">837</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#862">862</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#867">867</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#884">884</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#945">945</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#952">952</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#969">969</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#972">972</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#973">973</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#979">979</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1023">1023</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1058">1058</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1060">1060</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1061">1061</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1077">1077</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1101">1101</a>.</li> 255<li>Changed the following issues from Tentatively Ready to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1013">1013</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1107">1107</a>.</li> 256<li>Changed the following issues from Open to NAD Future: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#255">255</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#423">423</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#523">523</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#708">708</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#760">760</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#839">839</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#877">877</a>.</li> 257<li>Changed the following issues from CD1 to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#823">823</a>.</li> 258<li>Changed the following issues from NAD Editorial to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#299">299</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#484">484</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#532">532</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#556">556</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#594">594</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#631">631</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#676">676</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#704">704</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#724">724</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#742">742</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#811">811</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#870">870</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#872">872</a>.</li> 259<li>Changed the following issues from Review to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#879">879</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#919">919</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#929">929</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#939">939</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#987">987</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1009">1009</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1093">1093</a>.</li> 260<li>Changed the following issues from Tentatively NAD to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#458">458</a>.</li> 261<li>Changed the following issues from Tentatively NAD Future to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#96">96</a>.</li> 262<li>Changed the following issues from Tentatively Ready to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#910">910</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#915">915</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#932">932</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#940">940</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#974">974</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#976">976</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#999">999</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1011">1011</a>.</li> 263<li>Changed the following issues from Open to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#149">149</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#419">419</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#430">430</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#498">498</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#564">564</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#565">565</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#630">630</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#659">659</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#696">696</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#711">711</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#716">716</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#723">723</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#788">788</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#834">834</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#838">838</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#847">847</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#857">857</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#859">859</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#876">876</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#881">881</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#883">883</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#886">886</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1004">1004</a>.</li> 264<li>Changed the following issues from Review to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#780">780</a>.</li> 265<li>Changed the following issues from Tentatively NAD to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#822">822</a>.</li> 266<li>Changed the following issues from Tentatively Ready to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#934">934</a>.</li> 267<li>Changed the following issues from NAD to Review: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#871">871</a>.</li> 268<li>Changed the following issues from Open to Review: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#397">397</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#408">408</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#473">473</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#671">671</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#836">836</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#868">868</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#889">889</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#893">893</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#930">930</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#954">954</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#962">962</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#967">967</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#968">968</a>.</li> 269<li>Changed the following issues from Tentatively NAD to Review: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#668">668</a>.</li> 270<li>Changed the following issues from Tentatively Ready to Review: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#950">950</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1100">1100</a>.</li> 271<li>Changed the following issues from Open to Tentatively NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#588">588</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#617">617</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#625">625</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#971">971</a>.</li> 272<li>Changed the following issues from Open to Tentatively NAD Future: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1031">1031</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1062">1062</a>.</li> 273<li>Changed the following issues from Open to Tentatively Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1012">1012</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1019">1019</a>.</li> 274<li>Changed the following issues from Tentatively Ready to WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#688">688</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#765">765</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#810">810</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#814">814</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#853">853</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#869">869</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#878">878</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#888">888</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#890">890</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#898">898</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#899">899</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#904">904</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#907">907</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#909">909</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#922">922</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#925">925</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#931">931</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#938">938</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#943">943</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#948">948</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#949">949</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#965">965</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#970">970</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#975">975</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#981">981</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#982">982</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#984">984</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#986">986</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#990">990</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#991">991</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#993">993</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#994">994</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#997">997</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#998">998</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1006">1006</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1014">1014</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1021">1021</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1037">1037</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1038">1038</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1039">1039</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1040">1040</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1044">1044</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1045">1045</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1065">1065</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1066">1066</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1070">1070</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1073">1073</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1103">1103</a>.</li> 275</ul></li> 276</ul> 277</li> 278<li>R65: 2792009-06-19 pre-Frankfurt mailing. 280<ul> 281<li><b>Summary:</b><ul> 282<li>378 open issues, up by 32.</li> 283<li>765 closed issues, up by 0.</li> 284<li>1143 issues total, up by 32.</li> 285</ul></li> 286<li><b>Details:</b><ul> 287<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1115">1115</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1116">1116</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1117">1117</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1118">1118</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1119">1119</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1120">1120</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1121">1121</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1122">1122</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1123">1123</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1124">1124</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1125">1125</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1126">1126</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1127">1127</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1128">1128</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1129">1129</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1130">1130</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1131">1131</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1132">1132</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1133">1133</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1134">1134</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1135">1135</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1136">1136</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1137">1137</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1138">1138</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1139">1139</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1140">1140</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1141">1141</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1142">1142</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1143">1143</a>.</li> 288<li>Added the following Open issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1112">1112</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1113">1113</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1114">1114</a>.</li> 289<li>Changed the following issues from Pending NAD Editorial to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#937">937</a>.</li> 290<li>Changed the following issues from New to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#696">696</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#716">716</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#727">727</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#865">865</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#900">900</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#911">911</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#916">916</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#917">917</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#920">920</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#933">933</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#935">935</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#941">941</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#947">947</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#951">951</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#953">953</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#954">954</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#955">955</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#956">956</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#977">977</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#978">978</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#985">985</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#989">989</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#996">996</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1033">1033</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1054">1054</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1056">1056</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1057">1057</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1059">1059</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1062">1062</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1068">1068</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1069">1069</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1071">1071</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1072">1072</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1076">1076</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1090">1090</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1092">1092</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1096">1096</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1098">1098</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1099">1099</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1105">1105</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1106">1106</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1108">1108</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1110">1110</a>.</li> 291<li>Changed the following issues from Review to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#817">817</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#971">971</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#992">992</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1004">1004</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1010">1010</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1012">1012</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1015">1015</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1019">1019</a>.</li> 292<li>Changed the following issues from New to Review: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#780">780</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#835">835</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#897">897</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#919">919</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#939">939</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#957">957</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#983">983</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1001">1001</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1080">1080</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1091">1091</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1093">1093</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1094">1094</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1095">1095</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1097">1097</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1102">1102</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1104">1104</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1111">1111</a>.</li> 293<li>Changed the following issues from Open to Review: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#921">921</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#987">987</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1087">1087</a>.</li> 294<li>Changed the following issues from New to Tentatively NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#568">568</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#701">701</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#702">702</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#785">785</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#863">863</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#903">903</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#912">912</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#918">918</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#946">946</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#995">995</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1074">1074</a>.</li> 295<li>Changed the following issues from Open to Tentatively NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#458">458</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#644">644</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#667">667</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#668">668</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#669">669</a>.</li> 296<li>Changed the following issues from Review to Tentatively NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#901">901</a>.</li> 297<li>Changed the following issues from Tentatively Ready to Tentatively NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#822">822</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#988">988</a>.</li> 298<li>Changed the following issues from New to Tentatively NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#837">837</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#862">862</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#867">867</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#927">927</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#945">945</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#952">952</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#969">969</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#972">972</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#973">973</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#979">979</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1058">1058</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1060">1060</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1061">1061</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1077">1077</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1101">1101</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1109">1109</a>.</li> 299<li>Changed the following issues from Open to Tentatively NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#424">424</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#825">825</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#830">830</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#884">884</a>.</li> 300<li>Changed the following issues from Review to Tentatively NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1023">1023</a>.</li> 301<li>Changed the following issues from Open to Tentatively NAD Future: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#96">96</a>.</li> 302<li>Changed the following issues from New to Tentatively Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#810">810</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#898">898</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#906">906</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#910">910</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#913">913</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#914">914</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#915">915</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#925">925</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#974">974</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#976">976</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#981">981</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#982">982</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#984">984</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#990">990</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#998">998</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#999">999</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1063">1063</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1067">1067</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1070">1070</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1073">1073</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1100">1100</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1103">1103</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1107">1107</a>.</li> 303<li>Changed the following issues from Open to Tentatively Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#688">688</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#814">814</a>.</li> 304<li>Changed the following issues from Review to Tentatively Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#899">899</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#907">907</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#909">909</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#934">934</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#938">938</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#940">940</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#943">943</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#950">950</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#965">965</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#970">970</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#975">975</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#986">986</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#991">991</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#993">993</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#994">994</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#997">997</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1002">1002</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1006">1006</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1011">1011</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1013">1013</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1014">1014</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1021">1021</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1024">1024</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1037">1037</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1038">1038</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1039">1039</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1040">1040</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1044">1044</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1045">1045</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1065">1065</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1066">1066</a>.</li> 305</ul></li> 306</ul> 307</li> 308<li>R64: 3092009-05-01 mid-term mailing. 310<ul> 311<li><b>Summary:</b><ul> 312<li>346 open issues, up by 19.</li> 313<li>765 closed issues, up by 0.</li> 314<li>1111 issues total, up by 19.</li> 315</ul></li> 316<li><b>Details:</b><ul> 317<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1093">1093</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1094">1094</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1095">1095</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1096">1096</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1097">1097</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1098">1098</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1099">1099</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1100">1100</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1101">1101</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1102">1102</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1103">1103</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1104">1104</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1105">1105</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1106">1106</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1107">1107</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1108">1108</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1109">1109</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1110">1110</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1111">1111</a>.</li> 318<li>Changed the following issues from DR to CD1: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#130">130</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#386">386</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#406">406</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#409">409</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#413">413</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#434">434</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#438">438</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#444">444</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#445">445</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#455">455</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#457">457</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#460">460</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#469">469</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#533">533</a>.</li> 319<li>Changed the following issues from Review to New: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1070">1070</a>.</li> 320</ul></li> 321</ul> 322</li> 323<li>R63: 3242009-03-20 post-Summit mailing. 325<ul> 326<li><b>Summary:</b><ul> 327<li>327 open issues, up by 96.</li> 328<li>765 closed issues, up by 14.</li> 329<li>1092 issues total, up by 110.</li> 330</ul></li> 331<li><b>Details:</b><ul> 332<li>Added the following NAD Editorial issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1022">1022</a>.</li> 333<li>Added the following NAD Future issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1025">1025</a>.</li> 334<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#983">983</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#984">984</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#985">985</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#989">989</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#990">990</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#995">995</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#996">996</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#998">998</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#999">999</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1001">1001</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1033">1033</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1054">1054</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1056">1056</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1057">1057</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1058">1058</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1059">1059</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1060">1060</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1061">1061</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1062">1062</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1063">1063</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1067">1067</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1068">1068</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1069">1069</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1071">1071</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1072">1072</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1073">1073</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1074">1074</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1076">1076</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1077">1077</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1080">1080</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1090">1090</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1091">1091</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1092">1092</a>.</li> 335<li>Added the following Open issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#987">987</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1000">1000</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1007">1007</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1008">1008</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1016">1016</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1017">1017</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1018">1018</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1020">1020</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1026">1026</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1027">1027</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1028">1028</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1029">1029</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1030">1030</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1031">1031</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1032">1032</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1034">1034</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1035">1035</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1036">1036</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1041">1041</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1042">1042</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1046">1046</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1048">1048</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1051">1051</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1052">1052</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1053">1053</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1055">1055</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1064">1064</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1075">1075</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1078">1078</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1079">1079</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1081">1081</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1082">1082</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1083">1083</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1084">1084</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1085">1085</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1086">1086</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1087">1087</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1088">1088</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1089">1089</a>.</li> 336<li>Added the following Review issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#986">986</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#991">991</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#992">992</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#993">993</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#994">994</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#997">997</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1002">1002</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1003">1003</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1004">1004</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1005">1005</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1006">1006</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1009">1009</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1010">1010</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1011">1011</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1012">1012</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1013">1013</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1014">1014</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1015">1015</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1019">1019</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1021">1021</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1023">1023</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1024">1024</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1037">1037</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1038">1038</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1039">1039</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1040">1040</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1043">1043</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1044">1044</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1045">1045</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1047">1047</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1049">1049</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1050">1050</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1065">1065</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1066">1066</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1070">1070</a>.</li> 337<li>Added the following Tentatively Ready issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#988">988</a>.</li> 338<li>Changed the following issues from New to Dup: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#905">905</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#942">942</a>.</li> 339<li>Changed the following issues from New to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#980">980</a>.</li> 340<li>Changed the following issues from New to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#874">874</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#875">875</a>.</li> 341<li>Changed the following issues from Open to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#732">732</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#793">793</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#794">794</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#800">800</a>.</li> 342<li>Changed the following issues from Pending NAD Editorial to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#683">683</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#892">892</a>.</li> 343<li>Changed the following issues from Ready to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#803">803</a>.</li> 344<li>Changed the following issues from NAD to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#466">466</a>.</li> 345<li>Changed the following issues from NAD Future to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#111">111</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#138">138</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#149">149</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#219">219</a>.</li> 346<li>Changed the following issues from New to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#880">880</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#891">891</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#893">893</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#902">902</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#908">908</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#921">921</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#923">923</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#924">924</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#926">926</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#930">930</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#936">936</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#944">944</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#958">958</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#959">959</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#960">960</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#961">961</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#962">962</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#963">963</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#964">964</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#966">966</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#967">967</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#968">968</a>.</li> 347<li>Changed the following issues from Ready to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#788">788</a>.</li> 348<li>Changed the following issues from New to Pending NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#937">937</a>.</li> 349<li>Changed the following issues from New to Review: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#879">879</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#899">899</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#901">901</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#907">907</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#909">909</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#929">929</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#934">934</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#938">938</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#940">940</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#943">943</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#950">950</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#965">965</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#970">970</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#971">971</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#975">975</a>.</li> 350<li>Changed the following issues from Open to Review: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#817">817</a>.</li> 351<li>Changed the following issues from New to Tentatively Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#904">904</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#922">922</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#928">928</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#931">931</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#932">932</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#948">948</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#949">949</a>.</li> 352<li>Changed the following issues from Open to Tentatively Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#890">890</a>.</li> 353<li>Changed the following issues from Review to Tentatively Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#765">765</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#822">822</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#853">853</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#869">869</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#878">878</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#888">888</a>.</li> 354<li>Changed the following issues from Ready to WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#752">752</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#753">753</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#758">758</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#821">821</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#866">866</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#894">894</a>.</li> 355</ul></li> 356</ul> 357</li> 358<li>R62: 3592009-02-06 pre-Summit mailing. 360<ul> 361<li><b>Summary:</b><ul> 362<li>231 open issues, up by 44.</li> 363<li>751 closed issues, up by 0.</li> 364<li>982 issues total, up by 44.</li> 365</ul></li> 366<li><b>Details:</b><ul> 367<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#939">939</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#940">940</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#941">941</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#942">942</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#943">943</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#944">944</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#945">945</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#946">946</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#947">947</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#948">948</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#949">949</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#950">950</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#951">951</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#952">952</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#953">953</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#954">954</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#955">955</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#956">956</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#957">957</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#958">958</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#959">959</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#960">960</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#961">961</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#962">962</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#963">963</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#964">964</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#965">965</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#966">966</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#967">967</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#968">968</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#969">969</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#970">970</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#971">971</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#972">972</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#973">973</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#974">974</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#975">975</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#976">976</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#977">977</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#978">978</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#979">979</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#980">980</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#981">981</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#982">982</a>.</li> 368</ul></li> 369</ul> 370</li> 371<li>R61: 3722008-12-05 mid-term mailing. 373<ul> 374<li><b>Summary:</b><ul> 375<li>187 open issues, up by 20.</li> 376<li>751 closed issues, up by 0.</li> 377<li>938 issues total, up by 20.</li> 378</ul></li> 379<li><b>Details:</b><ul> 380<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#919">919</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#920">920</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#921">921</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#922">922</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#923">923</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#924">924</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#925">925</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#926">926</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#927">927</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#928">928</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#929">929</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#930">930</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#931">931</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#932">932</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#933">933</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#934">934</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#935">935</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#936">936</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#937">937</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#938">938</a>.</li> 381</ul></li> 382</ul> 383</li> 384<li>R60: 3852008-10-03 post-San Francisco mailing. 386<ul> 387<li><b>Summary:</b><ul> 388<li>167 open issues, down by 25.</li> 389<li>751 closed issues, up by 65.</li> 390<li>918 issues total, up by 40.</li> 391</ul></li> 392<li><b>Details:</b><ul> 393<li>Added the following CD1 issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#882">882</a>.</li> 394<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#879">879</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#880">880</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#891">891</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#893">893</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#897">897</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#898">898</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#899">899</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#900">900</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#901">901</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#902">902</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#903">903</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#904">904</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#905">905</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#906">906</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#907">907</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#908">908</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#909">909</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#910">910</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#911">911</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#912">912</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#913">913</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#914">914</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#915">915</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#916">916</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#917">917</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#918">918</a>.</li> 395<li>Added the following Open issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#881">881</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#883">883</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#884">884</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#885">885</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#886">886</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#887">887</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#889">889</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#890">890</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#895">895</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#896">896</a>.</li> 396<li>Added the following Pending NAD Editorial issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#892">892</a>.</li> 397<li>Added the following Ready issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#894">894</a>.</li> 398<li>Added the following Review issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#888">888</a>.</li> 399<li>Changed the following issues from New to CD1: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#818">818</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#820">820</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#843">843</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#845">845</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#846">846</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#856">856</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#858">858</a>.</li> 400<li>Changed the following issues from Ready to CD1: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#180">180</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#387">387</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#396">396</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#522">522</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#629">629</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#691">691</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#713">713</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#714">714</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#720">720</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#728">728</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#762">762</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#769">769</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#771">771</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#772">772</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#776">776</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#779">779</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#787">787</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#805">805</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#806">806</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#807">807</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#808">808</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#809">809</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#813">813</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#824">824</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#829">829</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#842">842</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#844">844</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#848">848</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#850">850</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#852">852</a>.</li> 401<li>Changed the following issues from Review to CD1: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#23">23</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#675">675</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#692">692</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#698">698</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#709">709</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#734">734</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#804">804</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#823">823</a>.</li> 402<li>Changed the following issues from WP to CD1: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#44">44</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#49">49</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#76">76</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#91">91</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#92">92</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#98">98</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#103">103</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#109">109</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#117">117</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#118">118</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#120">120</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#123">123</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#136">136</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#153">153</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#165">165</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#167">167</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#171">171</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#179">179</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#182">182</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#183">183</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#184">184</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#185">185</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#186">186</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#187">187</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#198">198</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#200">200</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#201">201</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#202">202</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#206">206</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#214">214</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#221">221</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#225">225</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#226">226</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#228">228</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#229">229</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#230">230</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#231">231</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#232">232</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#233">233</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#234">234</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#235">235</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#237">237</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#238">238</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#239">239</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#240">240</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#241">241</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#242">242</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#243">243</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#247">247</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#248">248</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#250">250</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#251">251</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#252">252</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#253">253</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#254">254</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#256">256</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#258">258</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#259">259</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#260">260</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#261">261</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#262">262</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#263">263</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#264">264</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#265">265</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#266">266</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#268">268</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#270">270</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#271">271</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#272">272</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#273">273</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#274">274</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#275">275</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#276">276</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#278">278</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#280">280</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#281">281</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#282">282</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#283">283</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#284">284</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#285">285</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#286">286</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#288">288</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#291">291</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#292">292</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#294">294</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#295">295</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#297">297</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#298">298</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#300">300</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#301">301</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#303">303</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#305">305</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#306">306</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#307">307</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#308">308</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#310">310</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#311">311</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#312">312</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#315">315</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#316">316</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#317">317</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#318">318</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#319">319</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#320">320</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#321">321</a>, <a 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href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#666">666</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#672">672</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#673">673</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#674">674</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#677">677</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#678">678</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#679">679</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#680">680</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#681">681</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#682">682</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#685">685</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#687">687</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#689">689</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#693">693</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#694">694</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#695">695</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#699">699</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#700">700</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#703">703</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#705">705</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#706">706</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#710">710</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#712">712</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#715">715</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#722">722</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#740">740</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#743">743</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#744">744</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#746">746</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#749">749</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#755">755</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#759">759</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#761">761</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#766">766</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#768">768</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#770">770</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#775">775</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#777">777</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#778">778</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#781">781</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#782">782</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#783">783</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#789">789</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#792">792</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#798">798</a>.</li> 403<li>Changed the following issues from Open to Dup: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#670">670</a>.</li> 404<li>Changed the following issues from New to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#849">849</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#855">855</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#871">871</a>.</li> 405<li>Changed the following issues from Open to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#454">454</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#832">832</a>.</li> 406<li>Changed the following issues from New to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#811">811</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#812">812</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#841">841</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#864">864</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#870">870</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#872">872</a>.</li> 407<li>Changed the following issues from Open to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#299">299</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#484">484</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#556">556</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#631">631</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#676">676</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#704">704</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#724">724</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#742">742</a>.</li> 408<li>Changed the following issues from Pending NAD Editorial to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#532">532</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#594">594</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#717">717</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#725">725</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#738">738</a>.</li> 409<li>Changed the following issues from New to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#721">721</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#751">751</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#814">814</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#816">816</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#817">817</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#819">819</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#827">827</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#836">836</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#838">838</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#847">847</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#857">857</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#859">859</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#860">860</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#861">861</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#868">868</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#873">873</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#876">876</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#877">877</a>.</li> 410<li>Changed the following issues from Pending NAD Editorial to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#424">424</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#625">625</a>.</li> 411<li>Changed the following issues from Review to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#851">851</a>.</li> 412<li>Changed the following issues from New to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#788">788</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#821">821</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#866">866</a>.</li> 413<li>Changed the following issues from Open to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#753">753</a>.</li> 414<li>Changed the following issues from Review to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#752">752</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#758">758</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#803">803</a>.</li> 415<li>Changed the following issues from New to Review: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#765">765</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#822">822</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#853">853</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#854">854</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#869">869</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#878">878</a>.</li> 416<li>Changed the following issues from TC to TC1: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1">1</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#3">3</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#5">5</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#7">7</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#8">8</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#9">9</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#11">11</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#13">13</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#14">14</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#15">15</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#16">16</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#17">17</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#18">18</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#19">19</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#20">20</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#21">21</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#22">22</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#24">24</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#25">25</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#26">26</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#27">27</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#28">28</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#29">29</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#30">30</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#31">31</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#32">32</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#33">33</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#34">34</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#35">35</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#36">36</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#37">37</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#38">38</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#39">39</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#40">40</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#41">41</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#42">42</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#46">46</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#47">47</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#48">48</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#50">50</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#51">51</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#52">52</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#53">53</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#54">54</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#55">55</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#56">56</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#57">57</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#59">59</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#60">60</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#61">61</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#62">62</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#63">63</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#64">64</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#66">66</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#68">68</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#69">69</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#70">70</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#71">71</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#74">74</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#75">75</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#78">78</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#79">79</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#80">80</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#83">83</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#86">86</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#90">90</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#106">106</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#108">108</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#110">110</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#112">112</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#114">114</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#115">115</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#119">119</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#122">122</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#124">124</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#125">125</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#126">126</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#127">127</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#129">129</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#132">132</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#133">133</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#134">134</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#137">137</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#139">139</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#141">141</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#142">142</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#144">144</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#146">146</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#147">147</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#148">148</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#150">150</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#151">151</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#152">152</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#154">154</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#155">155</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#156">156</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#158">158</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#159">159</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#160">160</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#161">161</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#164">164</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#168">168</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#169">169</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#170">170</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#172">172</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#173">173</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#174">174</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#175">175</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#176">176</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#181">181</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#189">189</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#193">193</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#195">195</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#199">199</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#208">208</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#209">209</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#210">210</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#211">211</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#212">212</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#217">217</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#220">220</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#222">222</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#223">223</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#224">224</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#227">227</a>.</li> 417</ul></li> 418</ul> 419</li> 420<li>R59: 4212008-08-22 pre-San Francisco mailing. 422<ul> 423<li><b>Summary:</b><ul> 424<li>192 open issues, up by 9.</li> 425<li>686 closed issues, up by 0.</li> 426<li>878 issues total, up by 9.</li> 427</ul></li> 428<li><b>Details:</b><ul> 429<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#870">870</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#871">871</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#872">872</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#873">873</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#874">874</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#875">875</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#876">876</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#877">877</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#878">878</a>.</li> 430</ul></li> 431</ul> 432</li> 433<li>R58: 4342008-07-28 mid-term mailing. 435<ul> 436<li><b>Summary:</b><ul> 437<li>183 open issues, up by 12.</li> 438<li>686 closed issues, down by 4.</li> 439<li>869 issues total, up by 8.</li> 440</ul></li> 441<li><b>Details:</b><ul> 442<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#862">862</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#863">863</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#864">864</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#865">865</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#866">866</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#867">867</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#868">868</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#869">869</a>.</li> 443<li>Changed the following issues from Pending NAD Editorial to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#393">393</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#557">557</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#592">592</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#754">754</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#757">757</a>.</li> 444<li>Changed the following issues from Pending WP to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#644">644</a>.</li> 445<li>Changed the following issues from WP to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#387">387</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#629">629</a>.</li> 446<li>Changed the following issues from Pending NAD Editorial to Review: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#709">709</a>.</li> 447</ul></li> 448</ul> 449</li> 450<li>R57: 4512008-06-27 post-Sophia Antipolis mailing. 452<ul> 453<li><b>Summary:</b><ul> 454<li>171 open issues, down by 20.</li> 455<li>690 closed issues, up by 43.</li> 456<li>861 issues total, up by 23.</li> 457</ul></li> 458<li><b>Details:</b><ul> 459<li>Added the following NAD issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#840">840</a>.</li> 460<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#841">841</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#843">843</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#845">845</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#846">846</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#847">847</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#849">849</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#853">853</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#854">854</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#855">855</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#856">856</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#857">857</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#858">858</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#859">859</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#860">860</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#861">861</a>.</li> 461<li>Added the following Open issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#839">839</a>.</li> 462<li>Added the following Ready issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#842">842</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#844">844</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#848">848</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#850">850</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#852">852</a>.</li> 463<li>Added the following Review issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#851">851</a>.</li> 464<li>Changed the following issues from New to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#826">826</a>.</li> 465<li>Changed the following issues from Open to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#570">570</a>.</li> 466<li>Changed the following issues from New to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#786">786</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#831">831</a>.</li> 467<li>Changed the following issues from Open to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#756">756</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#767">767</a>.</li> 468<li>Changed the following issues from New to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#723">723</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#726">726</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#794">794</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#815">815</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#825">825</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#830">830</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#833">833</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#834">834</a>.</li> 469<li>Changed the following issues from Ready to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#471">471</a>.</li> 470<li>Changed the following issues from Review to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#539">539</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#711">711</a>.</li> 471<li>Changed the following issues from New to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#713">713</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#714">714</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#769">769</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#772">772</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#779">779</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#787">787</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#805">805</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#806">806</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#807">807</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#808">808</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#809">809</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#813">813</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#824">824</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#829">829</a>.</li> 472<li>Changed the following issues from Open to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#180">180</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#396">396</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#522">522</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#720">720</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#762">762</a>.</li> 473<li>Changed the following issues from Review to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#691">691</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#728">728</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#771">771</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#776">776</a>.</li> 474<li>Changed the following issues from New to Review: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#692">692</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#698">698</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#752">752</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#804">804</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#823">823</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#828">828</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#832">832</a>.</li> 475<li>Changed the following issues from Open to Review: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#23">23</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#675">675</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#734">734</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#803">803</a>.</li> 476<li>Changed the following issues from Ready to Review: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#758">758</a>.</li> 477<li>Changed the following issues from Ready to WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#387">387</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#518">518</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#550">550</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#574">574</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#595">595</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#596">596</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#612">612</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#618">618</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#629">629</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#638">638</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#672">672</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#673">673</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#685">685</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#710">710</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#715">715</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#722">722</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#740">740</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#743">743</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#744">744</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#746">746</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#749">749</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#755">755</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#759">759</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#761">761</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#766">766</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#768">768</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#770">770</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#775">775</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#777">777</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#778">778</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#781">781</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#782">782</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#783">783</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#789">789</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#792">792</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#798">798</a>.</li> 478</ul></li> 479</ul> 480</li> 481<li>R56: 4822008-05-16 pre-Sophia Antipolis mailing. 483<ul> 484<li><b>Summary:</b><ul> 485<li>191 open issues, up by 24.</li> 486<li>647 closed issues, up by 1.</li> 487<li>838 issues total, up by 25.</li> 488</ul></li> 489<li><b>Details:</b><ul> 490<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#814">814</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#815">815</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#816">816</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#817">817</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#818">818</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#819">819</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#820">820</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#821">821</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#822">822</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#823">823</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#824">824</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#825">825</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#826">826</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#827">827</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#828">828</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#829">829</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#830">830</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#831">831</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#832">832</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#833">833</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#834">834</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#835">835</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#836">836</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#837">837</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#838">838</a>.</li> 491<li>Changed the following issues from New to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#802">802</a>.</li> 492</ul></li> 493</ul> 494</li> 495<li>R55: 4962008-03-14 post-Bellevue mailing. 497<ul> 498<li><b>Summary:</b><ul> 499<li>167 open issues, down by 39.</li> 500<li>646 closed issues, up by 65.</li> 501<li>813 issues total, up by 26.</li> 502</ul></li> 503<li><b>Details:</b><ul> 504<li>Added the following Dup issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#795">795</a>.</li> 505<li>Added the following NAD issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#790">790</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#791">791</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#796">796</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#797">797</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#799">799</a>.</li> 506<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#788">788</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#794">794</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#802">802</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#804">804</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#805">805</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#806">806</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#807">807</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#808">808</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#809">809</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#810">810</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#811">811</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#812">812</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#813">813</a>.</li> 507<li>Added the following Open issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#793">793</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#800">800</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#801">801</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#803">803</a>.</li> 508<li>Added the following Ready issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#789">789</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#792">792</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#798">798</a>.</li> 509<li>Changed the following issues from NAD Future to Dup: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#116">116</a>.</li> 510<li>Changed the following issues from NAD Future to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#188">188</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#323">323</a>.</li> 511<li>Changed the following issues from New to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#729">729</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#730">730</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#731">731</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#733">733</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#735">735</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#736">736</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#737">737</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#739">739</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#741">741</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#745">745</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#748">748</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#763">763</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#764">764</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#773">773</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#784">784</a>.</li> 512<li>Changed the following issues from Open to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#388">388</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#462">462</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#579">579</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#627">627</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#653">653</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#686">686</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#707">707</a>.</li> 513<li>Changed the following issues from NAD Future to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#140">140</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#390">390</a>.</li> 514<li>Changed the following issues from Open to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#529">529</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#626">626</a>.</li> 515<li>Changed the following issues from Review to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#645">645</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#684">684</a>.</li> 516<li>Changed the following issues from NAD Future to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#128">128</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#180">180</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#190">190</a>.</li> 517<li>Changed the following issues from New to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#617">617</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#718">718</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#719">719</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#720">720</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#724">724</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#732">732</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#734">734</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#742">742</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#747">747</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#750">750</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#753">753</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#756">756</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#760">760</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#762">762</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#767">767</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#774">774</a>.</li> 518<li>Changed the following issues from Ready to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#675">675</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#676">676</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#688">688</a>.</li> 519<li>Changed the following issues from New to Pending NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#709">709</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#717">717</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#725">725</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#738">738</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#754">754</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#757">757</a>.</li> 520<li>Changed the following issues from Open to Pending NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#424">424</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#557">557</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#625">625</a>.</li> 521<li>Changed the following issues from New to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#710">710</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#715">715</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#722">722</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#740">740</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#743">743</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#744">744</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#746">746</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#749">749</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#755">755</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#758">758</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#759">759</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#761">761</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#766">766</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#768">768</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#770">770</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#775">775</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#777">777</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#778">778</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#781">781</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#782">782</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#783">783</a>.</li> 522<li>Changed the following issues from Open to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#387">387</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#471">471</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#550">550</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#612">612</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#629">629</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#673">673</a>.</li> 523<li>Changed the following issues from Review to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#518">518</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#574">574</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#596">596</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#618">618</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#638">638</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#672">672</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#685">685</a>.</li> 524<li>Changed the following issues from New to Review: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#711">711</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#728">728</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#771">771</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#776">776</a>.</li> 525<li>Changed the following issues from Open to Review: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#539">539</a>.</li> 526<li>Changed the following issues from Ready to WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#561">561</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#562">562</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#563">563</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#567">567</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#581">581</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#620">620</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#621">621</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#622">622</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#623">623</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#624">624</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#661">661</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#664">664</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#665">665</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#666">666</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#674">674</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#679">679</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#680">680</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#687">687</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#689">689</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#693">693</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#694">694</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#695">695</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#700">700</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#703">703</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#705">705</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#706">706</a>.</li> 527<li>Changed the following issues from Tentatively Ready to WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#527">527</a>.</li> 528</ul></li> 529</ul> 530</li> 531<li>R54: 5322008-02-01 pre-Bellevue mailing. 533<ul> 534<li><b>Summary:</b><ul> 535<li>206 open issues, up by 23.</li> 536<li>581 closed issues, up by 0.</li> 537<li>787 issues total, up by 23.</li> 538</ul></li> 539<li><b>Details:</b><ul> 540<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#765">765</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#766">766</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#767">767</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#768">768</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#769">769</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#770">770</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#771">771</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#772">772</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#773">773</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#774">774</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#775">775</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#776">776</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#777">777</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#778">778</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#779">779</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#780">780</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#781">781</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#782">782</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#783">783</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#784">784</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#785">785</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#786">786</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#787">787</a>.</li> 541<li>Changed the following issues from NAD Future to Dup: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#105">105</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#348">348</a>.</li> 542<li>Changed the following issues from NAD Future to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#353">353</a>.</li> 543<li>Changed the following issues from New to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#697">697</a>.</li> 544<li>Changed the following issues from NAD Future to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#388">388</a>.</li> 545<li>Changed the following issues from Open to Tentatively Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#527">527</a>.</li> 546</ul></li> 547</ul> 548</li> 549<li>R53: 5502007-12-09 mid-term mailing. 551<ul> 552<li><b>Summary:</b><ul> 553<li>183 open issues, up by 11.</li> 554<li>581 closed issues, down by 1.</li> 555<li>764 issues total, up by 10.</li> 556</ul></li> 557<li><b>Details:</b><ul> 558<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#755">755</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#756">756</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#757">757</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#758">758</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#759">759</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#760">760</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#761">761</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#762">762</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#763">763</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#764">764</a>.</li> 559<li>Changed the following issues from NAD to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#463">463</a>.</li> 560<li>Changed the following issues from Pending WP to WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#607">607</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#608">608</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#654">654</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#655">655</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#677">677</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#682">682</a>.</li> 561</ul></li> 562</ul> 563</li> 564<li>R52: 5652007-10-19 post-Kona mailing. 566<ul> 567<li><b>Summary:</b><ul> 568<li>172 open issues, up by 4.</li> 569<li>582 closed issues, up by 27.</li> 570<li>754 issues total, up by 31.</li> 571</ul></li> 572<li><b>Details:</b><ul> 573<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#724">724</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#725">725</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#726">726</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#727">727</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#728">728</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#729">729</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#730">730</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#731">731</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#732">732</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#733">733</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#734">734</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#735">735</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#736">736</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#737">737</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#738">738</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#739">739</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#740">740</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#741">741</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#742">742</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#743">743</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#744">744</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#745">745</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#746">746</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#747">747</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#748">748</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#749">749</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#750">750</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#751">751</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#752">752</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#753">753</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#754">754</a>.</li> 574<li>Changed the following issues from NAD Future to Dup: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#77">77</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#350">350</a>.</li> 575<li>Changed the following issues from New to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#639">639</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#657">657</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#663">663</a>.</li> 576<li>Changed the following issues from Open to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#548">548</a>.</li> 577<li>Changed the following issues from New to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#546">546</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#550">550</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#564">564</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#565">565</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#573">573</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#585">585</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#588">588</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#627">627</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#629">629</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#630">630</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#632">632</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#635">635</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#653">653</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#659">659</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#667">667</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#668">668</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#669">669</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#670">670</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#671">671</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#673">673</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#686">686</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#704">704</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#707">707</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#708">708</a>.</li> 578<li>Changed the following issues from New to Pending NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#393">393</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#592">592</a>.</li> 579<li>Changed the following issues from New to Pending WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#607">607</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#608">608</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#654">654</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#655">655</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#677">677</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#682">682</a>.</li> 580<li>Changed the following issues from New to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#561">561</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#562">562</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#563">563</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#567">567</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#581">581</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#595">595</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#620">620</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#621">621</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#622">622</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#623">623</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#624">624</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#661">661</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#664">664</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#665">665</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#666">666</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#674">674</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#675">675</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#676">676</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#679">679</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#687">687</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#688">688</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#689">689</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#693">693</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#694">694</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#695">695</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#700">700</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#703">703</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#705">705</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#706">706</a>.</li> 581<li>Changed the following issues from Open to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#680">680</a>.</li> 582<li>Changed the following issues from New to Review: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#574">574</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#596">596</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#618">618</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#638">638</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#645">645</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#672">672</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#684">684</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#685">685</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#691">691</a>.</li> 583<li>Changed the following issues from New to WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#552">552</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#634">634</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#650">650</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#651">651</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#652">652</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#678">678</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#681">681</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#699">699</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#712">712</a>.</li> 584<li>Changed the following issues from Open to WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#258">258</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#401">401</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#524">524</a>.</li> 585<li>Changed the following issues from Ready to WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#488">488</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#577">577</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#660">660</a>.</li> 586</ul></li> 587</ul> 588</li> 589<li>R51: 5902007-09-09 pre-Kona mailing. 591<ul> 592<li><b>Summary:</b><ul> 593<li>168 open issues, up by 15.</li> 594<li>555 closed issues, up by 0.</li> 595<li>723 issues total, up by 15.</li> 596</ul></li> 597<li><b>Details:</b><ul> 598<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#709">709</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#710">710</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#711">711</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#712">712</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#713">713</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#714">714</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#715">715</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#716">716</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#717">717</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#718">718</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#719">719</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#720">720</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#721">721</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#722">722</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#723">723</a>.</li> 599</ul></li> 600</ul> 601</li> 602<li>R50: 6032007-08-05 post-Toronto mailing. 604<ul> 605<li><b>Summary:</b><ul> 606<li>153 open issues, down by 5.</li> 607<li>555 closed issues, up by 17.</li> 608<li>708 issues total, up by 12.</li> 609</ul></li> 610<li><b>Details:</b><ul> 611<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#697">697</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#698">698</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#699">699</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#700">700</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#701">701</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#702">702</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#703">703</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#704">704</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#705">705</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#706">706</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#707">707</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#708">708</a>.</li> 612<li>Changed the following issues from New to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#583">583</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#584">584</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#662">662</a>.</li> 613<li>Changed the following issues from Open to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#528">528</a>.</li> 614<li>Changed the following issues from New to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#637">637</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#647">647</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#658">658</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#690">690</a>.</li> 615<li>Changed the following issues from Open to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#525">525</a>.</li> 616<li>Changed the following issues from Pending NAD Editorial to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#553">553</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#571">571</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#591">591</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#633">633</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#636">636</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#641">641</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#642">642</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#648">648</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#649">649</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#656">656</a>.</li> 617<li>Changed the following issues from New to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#579">579</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#631">631</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#680">680</a>.</li> 618<li>Changed the following issues from Pending WP to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#258">258</a>.</li> 619<li>Changed the following issues from Ready to Pending WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#644">644</a>.</li> 620<li>Changed the following issues from New to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#577">577</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#660">660</a>.</li> 621<li>Changed the following issues from Open to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#488">488</a>.</li> 622<li>Changed the following issues from Open to Review: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#518">518</a>.</li> 623<li>Changed the following issues from Ready to TRDec: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#604">604</a>.</li> 624<li>Changed the following issues from DR to WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#453">453</a>.</li> 625<li>Changed the following issues from Ready to WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#531">531</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#551">551</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#566">566</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#628">628</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#640">640</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#643">643</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#646">646</a>.</li> 626</ul></li> 627</ul> 628</li> 629<li>R49: 6302007-06-23 pre-Toronto mailing. 631<ul> 632<li><b>Summary:</b><ul> 633<li>158 open issues, up by 13.</li> 634<li>538 closed issues, up by 7.</li> 635<li>696 issues total, up by 20.</li> 636</ul></li> 637<li><b>Details:</b><ul> 638<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#677">677</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#678">678</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#679">679</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#680">680</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#681">681</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#682">682</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#684">684</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#685">685</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#686">686</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#687">687</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#688">688</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#689">689</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#690">690</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#691">691</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#692">692</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#693">693</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#694">694</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#695">695</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#696">696</a>.</li> 639<li>Added the following Pending NAD Editorial issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#683">683</a>.</li> 640<li>Changed the following issues from New to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#587">587</a>.</li> 641<li>Changed the following issues from Open to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#590">590</a>.</li> 642<li>Changed the following issues from New to Pending NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#636">636</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#642">642</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#648">648</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#649">649</a>.</li> 643</ul></li> 644</ul> 645</li> 646<li>R48: 6472007-05-06 post-Oxford mailing. 648<ul> 649<li><b>Summary:</b><ul> 650<li>145 open issues, down by 33.</li> 651<li>531 closed issues, up by 53.</li> 652<li>676 issues total, up by 20.</li> 653</ul></li> 654<li><b>Details:</b><ul> 655<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#657">657</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#658">658</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#659">659</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#660">660</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#661">661</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#662">662</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#663">663</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#664">664</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#665">665</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#666">666</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#667">667</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#668">668</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#669">669</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#670">670</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#671">671</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#672">672</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#673">673</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#674">674</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#675">675</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#676">676</a>.</li> 656<li>Changed the following issues from Tentatively Ready to Dup: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#479">479</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#536">536</a>.</li> 657<li>Changed the following issues from Tentatively Ready to NAD: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#385">385</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#463">463</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#466">466</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#470">470</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#515">515</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#526">526</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#547">547</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#560">560</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#572">572</a>.</li> 658<li>Changed the following issues from NAD to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#351">351</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#357">357</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#368">368</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#499">499</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#504">504</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#512">512</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#513">513</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#514">514</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#516">516</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#544">544</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#549">549</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#555">555</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#558">558</a>.</li> 659<li>Changed the following issues from Tentatively Ready to NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#482">482</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#615">615</a>.</li> 660<li>Changed the following issues from NAD_Future to NAD Future: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#77">77</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#105">105</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#111">111</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#116">116</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#128">128</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#138">138</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#140">140</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#149">149</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#180">180</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#188">188</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#190">190</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#219">219</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#323">323</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#348">348</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#350">350</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#353">353</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#388">388</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#390">390</a>.</li> 661<li>Changed the following issues from Tentatively Ready to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#471">471</a>.</li> 662<li>Changed the following issues from New to Pending NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#633">633</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#641">641</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#656">656</a>.</li> 663<li>Changed the following issues from Tentatively Ready to Pending NAD Editorial: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#532">532</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#553">553</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#571">571</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#591">591</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#594">594</a>.</li> 664<li>Changed the following issues from Tentatively Ready to Pending WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#258">258</a>.</li> 665<li>Changed the following issues from New to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#566">566</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#628">628</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#640">640</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#643">643</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#644">644</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#646">646</a>.</li> 666<li>Changed the following issues from Review to Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#531">531</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#551">551</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#604">604</a>.</li> 667<li>Changed the following issues from Ready to TRDec: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#598">598</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#599">599</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#600">600</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#601">601</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#602">602</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#603">603</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#605">605</a>.</li> 668<li>Changed the following issues from Ready to WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#543">543</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#545">545</a>.</li> 669<li>Changed the following issues from Tentatively Ready to WP: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#201">201</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#206">206</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#233">233</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#254">254</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#416">416</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#422">422</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#456">456</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#534">534</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#542">542</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#559">559</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#575">575</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#576">576</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#578">578</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#586">586</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#589">589</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#593">593</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#609">609</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#610">610</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#611">611</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#613">613</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#616">616</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#619">619</a>.</li> 670</ul></li> 671</ul> 672</li> 673<li>R47: 6742007-03-09 pre-Oxford mailing. 675<ul> 676<li><b>Summary:</b><ul> 677<li>178 open issues, up by 37.</li> 678<li>478 closed issues, up by 0.</li> 679<li>656 issues total, up by 37.</li> 680</ul></li> 681<li><b>Details:</b><ul> 682<li>Added the following New issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#620">620</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#621">621</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#622">622</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#623">623</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#624">624</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#627">627</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#628">628</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#629">629</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#630">630</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#631">631</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#632">632</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#633">633</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#634">634</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#635">635</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#636">636</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#637">637</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#638">638</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#639">639</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#640">640</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#641">641</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#642">642</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#643">643</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#644">644</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#645">645</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#646">646</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#647">647</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#648">648</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#649">649</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#650">650</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#651">651</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#652">652</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#653">653</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#654">654</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#655">655</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#656">656</a>.</li> 683<li>Added the following Open issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#625">625</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#626">626</a>.</li> 684<li>Changed the following issues from New to Open: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#570">570</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#580">580</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#582">582</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#590">590</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#612">612</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#614">614</a>.</li> 685<li>Changed the following issues from New to Tentatively Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#547">547</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#553">553</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#560">560</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#571">571</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#572">572</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#575">575</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#576">576</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#578">578</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#586">586</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#589">589</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#591">591</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#593">593</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#594">594</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#609">609</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#610">610</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#611">611</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#613">613</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#615">615</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#616">616</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#619">619</a>.</li> 686<li>Changed the following issues from Open to Tentatively Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#201">201</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#206">206</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#233">233</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#254">254</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#258">258</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#385">385</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#416">416</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#422">422</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#456">456</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#463">463</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#466">466</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#470">470</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#471">471</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#479">479</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#482">482</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#515">515</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#526">526</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#532">532</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#536">536</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#542">542</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#559">559</a>.</li> 687<li>Changed the following issues from Review to Tentatively Ready: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#534">534</a>.</li> 688</ul></li> 689</ul> 690</li> 691<li>R46: 6922007-01-12 mid-term mailing. 693<ul> 694<li><b>Summary:</b><ul> 695<li>141 open issues, up by 11.</li> 696<li>478 closed issues, down by 1.</li> 697<li>619 issues total, up by 10.</li> 698</ul></li> 699<li><b>Details:</b><ul> 700<li>Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#610">610</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#611">611</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#612">612</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#613">613</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#614">614</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#615">615</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#616">616</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#617">617</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#618">618</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#619">619</a>.</li> 701</ul></li> 702</ul> 703</li> 704<li>R45: 7052006-11-03 post-Portland mailing. 706<ul> 707<li><b>Summary:</b><ul> 708<li>130 open issues, up by 0.</li> 709<li>479 closed issues, up by 17.</li> 710<li>609 issues total, up by 17.</li> 711</ul></li> 712<li><b>Details:</b><ul> 713<li>Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#520">520</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#521">521</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#530">530</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#535">535</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#537">537</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#538">538</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#540">540</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#541">541</a> to WP.</li> 714<li>Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#504">504</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#512">512</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#516">516</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#544">544</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#549">549</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#554">554</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#555">555</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#558">558</a> to NAD.</li> 715<li>Moved issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#569">569</a> to Dup.</li> 716<li>Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#518">518</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#523">523</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#524">524</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#542">542</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#556">556</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#557">557</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#559">559</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#597">597</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#606">606</a> to Open.</li> 717<li>Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#543">543</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#545">545</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#549">549</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#549">549</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#598">598</a> - <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#603">603</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#605">605</a> to Ready.</li> 718<li>Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#531">531</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#551">551</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#604">604</a> to Review.</li> 719<li>Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#593">593</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#594">594</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#595">595</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#596">596</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#597">597</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#598">598</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#599">599</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#600">600</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#601">601</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#602">602</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#603">603</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#604">604</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#605">605</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#606">606</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#607">607</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#608">608</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#609">609</a>.</li> 720</ul></li> 721</ul> 722</li> 723<li>R44: 7242006-09-08 pre-Portland mailing. 725<ul> 726<li><b>Summary:</b><ul> 727<li>130 open issues, up by 6.</li> 728<li>462 closed issues, down by 1.</li> 729<li>592 issues total, up by 5.</li> 730</ul></li> 731<li><b>Details:</b><ul> 732<li>Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#583">583</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#584">584</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#585">585</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#586">586</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#587">587</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#588">588</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#589">589</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#590">590</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#591">591</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#592">592</a>.</li> 733</ul></li> 734</ul> 735</li> 736<li>R43: 7372006-06-23 mid-term mailing. 738<ul> 739<li><b>Summary:</b><ul> 740<li>124 open issues, up by 14.</li> 741<li>463 closed issues, down by 1.</li> 742<li>587 issues total, up by 13.</li> 743</ul></li> 744<li><b>Details:</b><ul> 745<li>Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#575">575</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#576">576</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#577">577</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#578">578</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#579">579</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#580">580</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#581">581</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#582">582</a>.</li> 746<li>Reopened <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#255">255</a>.</li> 747<li>Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#520">520</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#541">541</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#544">544</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#569">569</a> to Tentatively Ready.</li> 748</ul></li> 749</ul> 750</li> 751<li>R42: 7522006-04-21 post-Berlin mailing. 753<ul> 754<li><b>Summary:</b><ul> 755<li>110 open issues, down by 16.</li> 756<li>464 closed issues, up by 24.</li> 757<li>574 issues total, up by 8.</li> 758</ul></li> 759<li><b>Details:</b><ul> 760<li>Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#567">567</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#568">568</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#569">569</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#570">570</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#571">571</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#572">572</a>.</li> 761<li>Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#499">499</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#501">501</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#506">506</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#509">509</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#510">510</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#511">511</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#513">513</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#514">514</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#517">517</a> to NAD.</li> 762<li>Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#502">502</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#503">503</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#515">515</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#516">516</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#522">522</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#525">525</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#526">526</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#527">527</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#528">528</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#529">529</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#532">532</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#536">536</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#539">539</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#548">548</a> to Open.</li> 763<li>Moved issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#504">504</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#512">512</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#521">521</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#530">530</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#531">531</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#535">535</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#537">537</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#538">538</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#540">540</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#549">549</a> to Ready.</li> 764<li>Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#247">247</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#294">294</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#362">362</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#369">369</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#371">371</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#376">376</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#384">384</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#475">475</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#478">478</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#495">495</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#497">497</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#505">505</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#507">507</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#508">508</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#519">519</a> to WP.</li> 765<li>Moved issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#534">534</a> to Review.</li> 766</ul></li> 767</ul> 768</li> 769<li>R41: 7702006-02-24 pre-Berlin mailing. 771<ul> 772<li><b>Summary:</b><ul> 773<li>126 open issues, up by 31.</li> 774<li>440 closed issues, up by 0.</li> 775<li>566 issues total, up by 31.</li> 776</ul></li> 777<li><b>Details:</b><ul> 778<li>Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#536">536</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#537">537</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#538">538</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#539">539</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#540">540</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#541">541</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#542">542</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#543">543</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#544">544</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#545">545</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#546">546</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#547">547</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#548">548</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#549">549</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#550">550</a> ,<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#551">551</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#552">552</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#553">553</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#554">554</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#555">555</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#556">556</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#557">557</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#558">558</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#559">559</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#560">560</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#561">561</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#562">562</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#563">563</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#564">564</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#565">565</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#566">566</a>.</li> 779<li>Moved <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#342">342</a> from Ready to Open.</li> 780<li>Reopened <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#309">309</a>.</li> 781</ul></li> 782</ul> 783</li> 784<li>R40: 7852005-12-16 mid-term mailing. 786<ul> 787<li><b>Summary:</b><ul> 788<li>95 open issues.</li> 789<li>440 closed issues.</li> 790<li>535 issues total.</li> 791</ul></li> 792<li><b>Details:</b><ul> 793<li>Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#529">529</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#530">530</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#531">531</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#532">532</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#533">533</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#534">534</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#535">535</a>.</li> 794</ul></li> 795</ul> 796</li> 797<li>R39: 7982005-10-14 post-Mont Tremblant mailing. 799Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#526">526</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#528">528</a>. 800Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#280">280</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#461">461</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#464">464</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#465">465</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#467">467</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#468">468</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#474">474</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#496">496</a> from Ready to WP as per the vote from Mont Tremblant. 801Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#247">247</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#294">294</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#342">342</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#362">362</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#369">369</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#371">371</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#376">376</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#384">384</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#475">475</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#478">478</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#495">495</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#497">497</a> from Review to Ready. 802Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#498">498</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#504">504</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#506">506</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#509">509</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#510">510</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#511">511</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#512">512</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#513">513</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#514">514</a> from New to Open. 803Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#505">505</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#507">507</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#508">508</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#519">519</a> from New to Ready. 804Moved issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#500">500</a> from New to NAD. 805Moved issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#518">518</a> from New to Review. 806</li> 807<li>R38: 8082005-07-03 pre-Mont Tremblant mailing. 809Merged open TR1 issues in <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#504">504</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#522">522</a>. 810Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#523">523</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#523">523</a> 811</li> 812<li>R37: 8132005-06 mid-term mailing. 814Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#498">498</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#503">503</a>. 815</li> 816<li>R36: 8172005-04 post-Lillehammer mailing. All issues in "ready" status except 818for <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#454">454</a> were moved to "DR" status, and all issues 819previously in "DR" status were moved to "WP". 820</li> 821<li>R35: 8222005-03 pre-Lillehammer mailing. 823</li> 824<li>R34: 8252005-01 mid-term mailing. Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#488">488</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#494">494</a>. 826</li> 827<li>R33: 8282004-11 post-Redmond mailing. Reflects actions taken in Redmond. 829</li> 830<li>R32: 8312004-09 pre-Redmond mailing: reflects new proposed resolutions and 832new issues received after the 2004-07 mailing. Added 833new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#479">479</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#481">481</a>. 834</li> 835<li>R31: 8362004-07 mid-term mailing: reflects new proposed resolutions and 837new issues received after the post-Sydney mailing. Added 838new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#463">463</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#478">478</a>. 839</li> 840<li>R30: 841Post-Sydney mailing: reflects decisions made at the Sydney meeting. 842Voted all "Ready" issues from R29 into the working paper. 843Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#460">460</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#462">462</a>. 844</li> 845<li>R29: 846Pre-Sydney mailing. Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#441">441</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#457">457</a>. 847</li> 848<li>R28: 849Post-Kona mailing: reflects decisions made at the Kona meeting. 850Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#432">432</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#440">440</a>. 851</li> 852<li>R27: 853Pre-Kona mailing. Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#404">404</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#431">431</a>. 854</li> 855<li>R26: 856Post-Oxford mailing: reflects decisions made at the Oxford meeting. 857All issues in Ready status were voted into DR status. All issues in 858DR status were voted into WP status. 859</li> 860<li>R25: 861Pre-Oxford mailing. Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#390">390</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#402">402</a>. 862</li> 863<li>R24: 864Post-Santa Cruz mailing: reflects decisions made at the Santa Cruz 865meeting. All Ready issues from R23 with the exception of <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#253">253</a>, which has been given a new proposed resolution, were 866moved to DR status. Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#383">383</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#389">389</a>. (Issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#387">387</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#389">389</a> were discussed 867at the meeting.) Made progress on issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#225">225</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#226">226</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#229">229</a>: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#225">225</a> and <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#229">229</a> have been moved to Ready status, and the only remaining 868concerns with <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#226">226</a> involve wording. 869</li> 870<li>R23: 871Pre-Santa Cruz mailing. Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#367">367</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#382">382</a>. 872Moved issues in the TC to TC status. 873</li> 874<li>R22: 875Post-Cura�ao mailing. Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#362">362</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#366">366</a>. 876</li> 877<li>R21: 878Pre-Cura�ao mailing. Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#351">351</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#361">361</a>. 879</li> 880<li>R20: 881Post-Redmond mailing; reflects actions taken in Redmond. Added 882new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#336">336</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#350">350</a>, of which issues 883<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#347">347</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#350">350</a> were added since Redmond, hence 884not discussed at the meeting. 885 886All Ready issues were moved to DR status, with the exception of issues 887<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#284">284</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#241">241</a>, and <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#267">267</a>. 888 889Noteworthy issues discussed at Redmond include 890<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#120">120</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#202">202</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#226">226</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#233">233</a>, 891<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#270">270</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#253">253</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#254">254</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#323">323</a>. 892</li> 893<li>R19: 894Pre-Redmond mailing. Added new issues 895<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#323">323</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#335">335</a>. 896</li> 897<li>R18: 898Post-Copenhagen mailing; reflects actions taken in Copenhagen. 899Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#312">312</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#317">317</a>, and discussed 900new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#271">271</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#314">314</a>. 901 902Changed status of issues 903<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#103">103</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#118">118</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#136">136</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#153">153</a> 904<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#165">165</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#171">171</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#183">183</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#184">184</a> 905<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#185">185</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#186">186</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#214">214</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#221">221</a> 906<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#234">234</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#237">237</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#243">243</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#248">248</a> 907<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#251">251</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#252">252</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#256">256</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#260">260</a> 908<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#261">261</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#262">262</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#263">263</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#265">265</a> 909<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#268">268</a> 910to DR. 911 912Changed status of issues 913<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#49">49</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#109">109</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#117">117</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#182">182</a> 914<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#228">228</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#230">230</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#232">232</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#235">235</a> 915<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#238">238</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#241">241</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#242">242</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#250">250</a> 916<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#259">259</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#264">264</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#266">266</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#267">267</a> 917<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#271">271</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#272">272</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#273">273</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#275">275</a> 918<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#281">281</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#284">284</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#285">285</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#286">286</a> 919<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#288">288</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#292">292</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#295">295</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#297">297</a> 920<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#298">298</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#301">301</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#303">303</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#306">306</a> 921<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#307">307</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#308">308</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#312">312</a> 922to Ready. 923 924Closed issues 925<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#111">111</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#277">277</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#279">279</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#287">287</a> 926<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#289">289</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#293">293</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#302">302</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#313">313</a> 927<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#314">314</a> 928as NAD. 929 930</li> 931<li>R17: 932Pre-Copenhagen mailing. Converted issues list to XML. Added proposed 933resolutions for issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#49">49</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#76">76</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#91">91</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#235">235</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#250">250</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#267">267</a>. 934Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#278">278</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#311">311</a>. 935</li> 936<li>R16: 937post-Toronto mailing; reflects actions taken in Toronto. Added new 938issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#265">265</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#277">277</a>. Changed status of issues 939<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#3">3</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#8">8</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#9">9</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#19">19</a>, 940<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#26">26</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#31">31</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#61">61</a>, 941<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#63">63</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#86">86</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#108">108</a>, 942<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#112">112</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#114">114</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#115">115</a>, 943<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#122">122</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#127">127</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#129">129</a>, 944<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#134">134</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#137">137</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#142">142</a>, 945<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#144">144</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#146">146</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#147">147</a>, 946<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#159">159</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#164">164</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#170">170</a>, 947<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#181">181</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#199">199</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#208">208</a>, 948<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#209">209</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#210">210</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#211">211</a>, 949<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#212">212</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#217">217</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#220">220</a>, 950<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#222">222</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#223">223</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#224">224</a>, 951<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#227">227</a> to "DR". Reopened issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#23">23</a>. Reopened 952issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#187">187</a>. Changed issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#2">2</a> and 953<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#4">4</a> to NAD. Fixed a typo in issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#17">17</a>. Fixed 954issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#70">70</a>: signature should be changed both places it 955appears. Fixed issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#160">160</a>: previous version didn't fix 956the bug in enough places. 957</li> 958<li>R15: 959pre-Toronto mailing. Added issues 960<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#233">233</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#264">264</a>. Some small HTML formatting 961changes so that we pass Weblint tests. 962</li> 963<li>R14: 964post-Tokyo II mailing; reflects committee actions taken in 965Tokyo. Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#228">228</a> to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#232">232</a>. (00-0019R1/N1242) 966</li> 967<li>R13: 968pre-Tokyo II updated: Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#212">212</a> to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#227">227</a>. 969</li> 970<li>R12: 971pre-Tokyo II mailing: Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#199">199</a> to 972<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#211">211</a>. Added "and paragraph 5" to the proposed resolution 973of issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#29">29</a>. Add further rationale to issue 974<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#178">178</a>. 975</li> 976<li>R11: 977post-Kona mailing: Updated to reflect LWG and full committee actions 978in Kona (99-0048/N1224). Note changed resolution of issues 979<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#4">4</a> and <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#38">38</a>. Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#196">196</a> 980to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#198">198</a>. Closed issues list split into "defects" and 981"closed" documents. Changed the proposed resolution of issue 982<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#4">4</a> to NAD, and changed the wording of proposed resolution 983of issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#38">38</a>. 984</li> 985<li>R10: 986pre-Kona updated. Added proposed resolutions <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#83">83</a>, 987<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#86">86</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#91">91</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#92">92</a>, 988<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#109">109</a>. Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#190">190</a> to 989<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#195">195</a>. (99-0033/D1209, 14 Oct 99) 990</li> 991<li>R9: 992pre-Kona mailing. Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#140">140</a> to 993<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#189">189</a>. Issues list split into separate "active" and 994"closed" documents. (99-0030/N1206, 25 Aug 99) 995</li> 996<li>R8: 997post-Dublin mailing. Updated to reflect LWG and full committee actions 998in Dublin. (99-0016/N1193, 21 Apr 99) 999</li> 1000<li>R7: 1001pre-Dublin updated: Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#130">130</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#131">131</a>, 1002<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#132">132</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#133">133</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#134">134</a>, 1003<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#135">135</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#136">136</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#137">137</a>, 1004<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#138">138</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#139">139</a> (31 Mar 99) 1005</li> 1006<li>R6: 1007pre-Dublin mailing. Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#127">127</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#128">128</a>, 1008and <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#129">129</a>. (99-0007/N1194, 22 Feb 99) 1009</li> 1010<li>R5: 1011update issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#103">103</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#112">112</a>; added issues 1012<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#114">114</a> to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#126">126</a>. Format revisions to prepare 1013for making list public. (30 Dec 98) 1014</li> 1015<li>R4: 1016post-Santa Cruz II updated: Issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#110">110</a>, 1017<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#111">111</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#112">112</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#113">113</a> added, several 1018issues corrected. (22 Oct 98) 1019</li> 1020<li>R3: 1021post-Santa Cruz II: Issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#94">94</a> to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#109">109</a> 1022added, many issues updated to reflect LWG consensus (12 Oct 98) 1023</li> 1024<li>R2: 1025pre-Santa Cruz II: Issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#73">73</a> to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#93">93</a> added, 1026issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#17">17</a> updated. (29 Sep 98) 1027</li> 1028<li>R1: 1029Correction to issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#55">55</a> resolution, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#60">60</a> code 1030format, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#64">64</a> title. (17 Sep 98) 1031</li> 1032</ul> 1033 1034<h2><a name="Status"></a>Issue Status</h2> 1035 1036 <p><b><a name="New">New</a></b> - The issue has not yet been 1037 reviewed by the LWG. Any <b>Proposed Resolution</b> is purely a 1038 suggestion from the issue submitter, and should not be construed as 1039 the view of LWG.</p> 1040 1041 <p><b><a name="Open">Open</a></b> - The LWG has discussed the issue 1042 but is not yet ready to move the issue forward. There are several 1043 possible reasons for open status:</p> 1044 <ul> 1045 <li>Consensus may have not yet have been reached as to how to deal 1046 with the issue.</li> 1047 <li>Informal consensus may have been reached, but the LWG awaits 1048 exact <b>Proposed Resolution</b> wording for review.</li> 1049 <li>The LWG wishes to consult additional technical experts before 1050 proceeding.</li> 1051 <li>The issue may require further study.</li> 1052 </ul> 1053 1054 <p>A <b>Proposed Resolution</b> for an open issue is still not be 1055 construed as the view of LWG. Comments on the current state of 1056 discussions are often given at the end of open issues in an italic 1057 font. Such comments are for information only and should not be given 1058 undue importance.</p> 1059 1060 <p><b><a name="Dup">Dup</a></b> - The LWG has reached consensus that 1061 the issue is a duplicate of another issue, and will not be further 1062 dealt with. A <b>Rationale</b> identifies the duplicated issue's 1063 issue number. </p> 1064 1065 <p><b><a name="NAD">NAD</a></b> - The LWG has reached consensus that 1066 the issue is not a defect in the Standard.</p> 1067 1068 <p><b><a name="NAD Editorial">NAD Editorial</a></b> - The LWG has reached consensus that 1069 the issue can either be handled editorially, or is handled by a paper (usually 1070 linked to in the rationale).</p> 1071 1072 <p><b><a name="NAD Concepts">NAD Concepts</a></b> - The LWG has reached consensus that 1073 the issue is NAD for now, but represents a real issue when the library is 1074 done with language-supported concepts.</p> 1075 1076 <p><b><a name="NAD Future">NAD Future</a></b> - In addition to the regular 1077 status, the LWG believes that this issue should be revisited at the 1078 next revision of the standard.</p> 1079 1080 <p><b><a name="Review">Review</a></b> - Exact wording of a 1081 <b>Proposed Resolution</b> is now available for review on an issue 1082 for which the LWG previously reached informal consensus.</p> 1083 1084 <p><b><a name="Ready">Ready</a></b> - The LWG has reached consensus 1085 that the issue is a defect in the Standard, the <b>Proposed 1086 Resolution</b> is correct, and the issue is ready to forward to the 1087 full committee for further action as a Defect Report (DR).</p> 1088 1089 <p><b><a name="DR">DR</a></b> - (Defect Report) - The full J16 1090 committee has voted to forward the issue to the Project Editor to be 1091 processed as a Potential Defect Report. The Project Editor reviews 1092 the issue, and then forwards it to the WG21 Convenor, who returns it 1093 to the full committee for final disposition. This issues list 1094 accords the status of DR to all these Defect Reports regardless of 1095 where they are in that process.</p> 1096 1097 <p><b><a name="TC1">TC1</a></b> - (Technical Corrigenda 1) - The full 1098 WG21 committee has voted to accept the Defect Report's Proposed 1099 Resolution as a Technical Corrigenda. Action on this issue is thus 1100 complete and no further action is possible under ISO rules.</p> 1101 1102 <p><b><a name="CD1">CD1</a></b> - (Committee Draft 2008) - The full 1103 WG21 committee has voted to accept the Defect Report's Proposed 1104 Resolution into the Fall 2008 Committee Draft.</p> 1105 1106 <p><b><a name="TRDec">TRDec</a></b> - (Decimal TR defect) - The 1107 LWG has voted to accept the Defect Report's Proposed 1108 Resolution into the Decimal TR. Action on this issue is thus 1109 complete and no further action is expected.</p> 1110 1111 <p><b><a name="WP">WP</a></b> - (Working Paper) - The proposed 1112 resolution has not been accepted as a Technical Corrigendum, but 1113 the full WG21 committee has voted to apply the Defect Report's Proposed 1114 Resolution to the working paper.</p> 1115 1116 <p><b>Tentatively</b> - This is a <i>status qualifier</i>. The issue has 1117 been reviewed online, or at an unofficial meeting, but not in an official meeting, and some support has been formed 1118 for the qualified status. Tentatively qualified issues may be moved to the unqualified status 1119 and forwarded to full committee (if Ready) within the same meeting. Unlike Ready issues, Tentatively Ready issues 1120 will be reviewed in subcommittee prior to forwarding to full committee. When a status is 1121 qualified with Tentatively, the issue is still considered active.</p> 1122 1123 <p><b>Pending</b> - This is a <i>status qualifier</i>. When prepended to 1124 a status this indicates the issue has been 1125 processed by the committee, and a decision has been made to move the issue to 1126 the associated unqualified status. However for logistical reasons the indicated 1127 outcome of the issue has not yet appeared in the latest working paper. 1128 1129 </p><p>Issues are always given the status of <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> when 1130 they first appear on the issues list. They may progress to 1131 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> or <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Review">Review</a> while the LWG 1132 is actively working on them. When the LWG has reached consensus on 1133 the disposition of an issue, the status will then change to 1134 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Dup">Dup</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">NAD</a>, or 1135 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> as appropriate. Once the full J16 committee votes to 1136 forward Ready issues to the Project Editor, they are given the 1137 status of Defect Report ( <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#DR">DR</a>). These in turn may 1138 become the basis for Technical Corrigenda (<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>), 1139 or are closed without action other than a Record of Response 1140 (<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#RR">RR</a> ). The intent of this LWG process is that 1141 only issues which are truly defects in the Standard move to the 1142 formal ISO DR status. 1143 </p> 1144 1145 1146<h2>Active Issues</h2> 1147<hr> 1148<h3><a name="296"></a>296. Missing descriptions and requirements of pair operators</h3> 1149<p><b>Section:</b> 20.3.4 [pairs] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 1150 <b>Submitter:</b> Martin Sebor <b>Opened:</b> 2001-01-14 <b>Last modified:</b> 2009-10-26</p> 1151<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#pairs">active issues</a> in [pairs].</p> 1152<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#pairs">issues</a> in [pairs].</p> 1153<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 1154<p><b>Discussion:</b></p> 1155<p>The synopsis of the header <tt><utility></tt> in 20.3 [utility] 1156lists the complete set of equality and relational operators for <tt>pair</tt> 1157but the section describing the template and the operators only describes 1158<tt>operator==()</tt> and <tt>operator<()</tt>, and it fails to mention 1159any requirements on the template arguments. The remaining operators are 1160not mentioned at all. 1161</p> 1162 1163<p><i>[ 11642009-09-27 Alisdair reopens. 1165]</i></p> 1166 1167 1168<blockquote> 1169<p> 1170The issue is a lack of wording specifying the semantics of <tt>std::pair</tt> 1171relational operators. The rationale is that this is covered by 1172catch-all wording in the relops component, and that as relops directly 1173precedes <tt>pair</tt> in the document this is an easy connection to make. 1174</p> 1175 1176<p> 1177Reading the current working paper I make two observations: 1178</p> 1179 1180<ol type="i"> 1181<li> 1182relops no longer immediately precedes <tt>pair</tt> in the order of 1183specification. However, even if it did, there is a lot of <tt>pair</tt> 1184specification itself between the (apparently) unrelated relops and the 1185relational operators for <tt>pair</tt>. (The catch-all still requires 1186<tt>operator==</tt> and <tt>operator<</tt> to be specified 1187explicitly) 1188</li> 1189 1190<li> 1191No other library component relies on the catch-all clause. The following 1192all explicitly document all six relational operators, usually in a 1193manner that could have deferred to the relops clause. 1194</li> 1195</ol> 1196 1197<blockquote><pre>tuple 1198unique_ptr 1199duration 1200time_point 1201basic_string 1202queue 1203stack 1204move_iterator 1205reverse_iterator 1206regex submatch 1207thread::id 1208</pre></blockquote> 1209 1210<p> 1211The container components provide their own (equivalent) definition in 121223.2.1 [container.requirements.general] Table 90 -- Container 1213requirements and do so do not defer to relops. 1214</p> 1215 1216<p> 1217<tt>Shared_ptr</tt> explicitly documents <tt>operator!=</tt> and does 1218not supply the other 3 missing operators 1219(<tt>></tt>,<tt>>=</tt>,<tt><=</tt>) so does not meet the 1220reqirements of the relops clause. 1221</p> 1222 1223<p> 1224<tt>Weak_ptr</tt> only supports <tt>operator<</tt> so would not be 1225covered by relops. 1226</p> 1227 1228<p> 1229At the very least I would request a note pointing to the relops clause 1230we rely on to provide this definition. If this route is taken, I would 1231recommend reducing many of the above listed clauses to a similar note 1232rather than providing redundant specification. 1233</p> 1234 1235<p> 1236My preference would be to supply the 4 missing specifications consistent 1237with the rest of the library. 1238</p> 1239 1240</blockquote> 1241 1242<p><i>[ 12432009-10-11 Daniel opens <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1233">1233</a> which deals with the same issue as 1244it pertains to <tt>unique_ptr</tt>. 1245]</i></p> 1246 1247 1248<p><i>[ 12492009-10 Santa Cruz: 1250]</i></p> 1251 1252 1253<blockquote> 1254Move to Ready 1255</blockquote> 1256 1257 1258 1259<p><b>Proposed resolution:</b></p> 1260<p> 1261After p20 20.3.4 [pairs] add: 1262</p> 1263 1264<blockquote><pre>template <class T1, class T2> 1265bool operator!=(const pair<T1,T2>& x, const pair<T1,T2>& y); 1266</pre> 1267 1268<blockquote> 1269<i>Returns:</i> <tt>!(x==y)</tt> 1270</blockquote> 1271 1272<pre>template <class T1, class T2> 1273bool operator> (const pair<T1,T2>& x, const pair<T1,T2>& y); 1274</pre> 1275 1276<blockquote> 1277<i>Returns:</i> <tt>y < x</tt> 1278</blockquote> 1279 1280<pre>template <class T1, class T2> 1281bool operator>=(const pair<T1,T2>& x, const pair<T1,T2>& y); 1282</pre> 1283 1284<blockquote> 1285<i>Returns:</i> <tt>!(x < y)</tt> 1286</blockquote> 1287 1288<pre>template <class T1, class T2> 1289bool operator<=(const pair<T1,T2>& x, const pair<T1,T2>& y); 1290</pre> 1291 1292<blockquote> 1293<i>Returns:</i> <tt>!(y < x)</tt> 1294</blockquote> 1295</blockquote> 1296 1297 1298<p><b>Rationale:</b></p> 1299<p>20.3.1 [operators] paragraph 10 already specifies the semantics. 1300That paragraph says that, if declarations of operator!=, operator>, 1301operator<=, and operator>= appear without definitions, they are 1302defined as specified in 20.3.1 [operators]. There should be no user 1303confusion, since that paragraph happens to immediately precede the 1304specification of <tt>pair</tt>.</p> 1305 1306 1307 1308 1309 1310<hr> 1311<h3><a name="299"></a>299. Incorrect return types for iterator dereference</h3> 1312<p><b>Section:</b> 24.2.4 [bidirectional.iterators], 24.2.5 [random.access.iterators] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 1313 <b>Submitter:</b> John Potter <b>Opened:</b> 2001-01-22 <b>Last modified:</b> 2009-10-26</p> 1314<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#bidirectional.iterators">issues</a> in [bidirectional.iterators].</p> 1315<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 1316<p><b>Discussion:</b></p> 1317<p> 1318In section 24.2.4 [bidirectional.iterators], 1319Table 75 gives the return type of *r-- as convertible to T. This is 1320not consistent with Table 74 which gives the return type of *r++ as 1321T&. *r++ = t is valid while *r-- = t is invalid. 1322</p> 1323 1324<p> 1325In section 24.2.5 [random.access.iterators], 1326Table 76 gives the return type of a[n] as convertible to T. This is 1327not consistent with the semantics of *(a + n) which returns T& by 1328Table 74. *(a + n) = t is valid while a[n] = t is invalid. 1329</p> 1330 1331<p> 1332Discussion from the Copenhagen meeting: the first part is 1333uncontroversial. The second part, operator[] for Random Access 1334Iterators, requires more thought. There are reasonable arguments on 1335both sides. Return by value from operator[] enables some potentially 1336useful iterators, e.g. a random access "iota iterator" (a.k.a 1337"counting iterator" or "int iterator"). There isn't any obvious way 1338to do this with return-by-reference, since the reference would be to a 1339temporary. On the other hand, <tt>reverse_iterator</tt> takes an 1340arbitrary Random Access Iterator as template argument, and its 1341operator[] returns by reference. If we decided that the return type 1342in Table 76 was correct, we would have to change 1343<tt>reverse_iterator</tt>. This change would probably affect user 1344code. 1345</p> 1346 1347<p> 1348History: the contradiction between <tt>reverse_iterator</tt> and the 1349Random Access Iterator requirements has been present from an early 1350stage. In both the STL proposal adopted by the committee 1351(N0527==94-0140) and the STL technical report (HPL-95-11 (R.1), by 1352Stepanov and Lee), the Random Access Iterator requirements say that 1353operator[]'s return value is "convertible to T". In N0527 1354reverse_iterator's operator[] returns by value, but in HPL-95-11 1355(R.1), and in the STL implementation that HP released to the public, 1356reverse_iterator's operator[] returns by reference. In 1995, the 1357standard was amended to reflect the contents of HPL-95-11 (R.1). The 1358original intent for operator[] is unclear. 1359</p> 1360 1361<p> 1362In the long term it may be desirable to add more fine-grained 1363iterator requirements, so that access method and traversal strategy 1364can be decoupled. (See "Improved Iterator Categories and 1365Requirements", N1297 = 01-0011, by Jeremy Siek.) Any decisions 1366about issue 299 should keep this possibility in mind. 1367</p> 1368 1369<p>Further discussion: I propose a compromise between John Potter's 1370resolution, which requires <tt>T&</tt> as the return type of 1371<tt>a[n]</tt>, and the current wording, which requires convertible to 1372<tt>T</tt>. The compromise is to keep the convertible to <tt>T</tt> 1373for the return type of the expression <tt>a[n]</tt>, but to also add 1374<tt>a[n] = t</tt> as a valid expression. This compromise "saves" the 1375common case uses of random access iterators, while at the same time 1376allowing iterators such as counting iterator and caching file 1377iterators to remain random access iterators (iterators where the 1378lifetime of the object returned by <tt>operator*()</tt> is tied to the 1379lifetime of the iterator). 1380</p> 1381 1382<p> 1383Note that the compromise resolution necessitates a change to 1384<tt>reverse_iterator</tt>. It would need to use a proxy to support 1385<tt>a[n] = t</tt>. 1386</p> 1387 1388<p> 1389Note also there is one kind of mutable random access iterator that 1390will no longer meet the new requirements. Currently, iterators that 1391return an r-value from <tt>operator[]</tt> meet the requirements for a 1392mutable random access iterartor, even though the expression <tt>a[n] = 1393t</tt> will only modify a temporary that goes away. With this proposed 1394resolution, <tt>a[n] = t</tt> will be required to have the same 1395operational semantics as <tt>*(a + n) = t</tt>. 1396</p> 1397 1398<p><i>[ 13992009-07-28 Reopened by Alisdair. No longer solved by concepts. 1400]</i></p> 1401 1402 1403<p><i>[ 14042009-09-18 Alisdair adds: 1405]</i></p> 1406 1407 1408<blockquote> 1409<p> 1410Why can't we write through the reference returned from operator[] on a 1411random access iterator? 1412</p> 1413 1414<p> 1415Recommended solution: 1416</p> 1417 1418<p> 1419In table Table 104 -- Random access iterator requirements, replace 1420</p> 1421 1422<blockquote> 1423a[n] : convertible to <del><tt>const T &</tt></del> 1424<ins><tt>T&</tt> if <tt>X</tt> is mutable, otherwise convertible to <tt>const T&</tt></ins> 1425</blockquote> 1426</blockquote> 1427 1428<p><i>[ 14292009-10 Santa Cruz: 1430]</i></p> 1431 1432 1433<blockquote> 1434Leave Open. Alisdair to spearhead a paper on revivification. 1435</blockquote> 1436 1437 1438 1439<p><b>Proposed resolution:</b></p> 1440 1441<p> 1442In section 24.1.4 [lib.bidirectdional.iterators], change the return 1443type in table 75 from "convertible to <tt>T</tt>" to 1444<tt>T&</tt>. 1445</p> 1446 1447<p> 1448In section 24.1.5 [lib.random.access.iterators], change the 1449operational semantics for <tt>a[n]</tt> to " the r-value of 1450<tt>a[n]</tt> is equivalent to the r-value of <tt>*(a + 1451n)</tt>". Add a new row in the table for the expression <tt>a[n] = t</tt> 1452with a return type of convertible to <tt>T</tt> and operational semantics of 1453<tt>*(a + n) = t</tt>. 1454</p> 1455 1456<p><i>[Lillehammer: Real problem, but should be addressed as part of 1457 iterator redesign]</i></p> 1458 1459 1460 1461 1462<p><b>Rationale:</b></p> 1463<p><i>[ 1464San Francisco: 1465]</i></p> 1466 1467 1468<blockquote> 1469Solved by 1470<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2758.pdf">N2758</a>. 1471</blockquote> 1472 1473 1474 1475 1476 1477 1478 1479<hr> 1480<h3><a name="397"></a>397. ostream::sentry dtor throws exceptions</h3> 1481<p><b>Section:</b> 27.7.2.4 [ostream::sentry] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 1482 <b>Submitter:</b> Martin Sebor <b>Opened:</b> 2003-01-05 <b>Last modified:</b> 2009-10-20</p> 1483<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#ostream::sentry">issues</a> in [ostream::sentry].</p> 1484<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 1485<p><b>Discussion:</b></p> 1486 <p> 148717.4.4.8, p3 prohibits library dtors from throwing exceptions. 1488 </p> 1489 <p> 149027.6.2.3, p4 says this about the ostream::sentry dtor: 1491 </p> 1492 <pre> -4- If ((os.flags() & ios_base::unitbuf) && !uncaught_exception()) 1493 is true, calls os.flush(). 1494 </pre> 1495 <p> 149627.6.2.6, p7 that describes ostream::flush() says: 1497 </p> 1498 <pre> -7- If rdbuf() is not a null pointer, calls rdbuf()->pubsync(). 1499 If that function returns ?-1 calls setstate(badbit) (which 1500 may throw ios_base::failure (27.4.4.3)). 1501 </pre> 1502 <p> 1503That seems like a defect, since both pubsync() and setstate() can 1504throw an exception. 1505 </p> 1506<p><i>[ 1507The contradiction is real. Clause 17 says destructors may never 1508throw exceptions, and clause 27 specifies a destructor that does 1509throw. In principle we might change either one. We're leaning 1510toward changing clause 17: putting in an "unless otherwise specified" 1511clause, and then putting in a footnote saying the sentry destructor 1512is the only one that can throw. PJP suggests specifying that 1513sentry::~sentry() should internally catch any exceptions it might cause. 1514]</i></p> 1515 1516 1517<p><i>[ 1518See <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#418">418</a> and <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#622">622</a> for related issues. 1519]</i></p> 1520 1521 1522<p><i>[ 15232009-07 Frankfurt 1524]</i></p> 1525 1526 1527<blockquote> 1528<p> 1529Move to Review. Add "Throws: nothing" to the specification of ostream::sentry::~sentry(). 1530</p> 1531</blockquote> 1532 1533<p><i>[ 15342009-10-13 Daniel adds: 1535]</i></p> 1536 1537 1538<blockquote> 1539The proposed resolution of <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#835">835</a> is written to match the outcome 1540of this issue. 1541</blockquote> 1542 1543<p><i>[ 15442009 Santa Cruz: 1545]</i></p> 1546 1547 1548<blockquote> 1549Move to Open. Our intent is to solve this issue with <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#835">835</a>. 1550</blockquote> 1551 1552 1553 1554<p><b>Proposed resolution:</b></p> 1555<p> 1556Add after 27.7.2.4 [ostream::sentry] p17: 1557</p> 1558 1559<blockquote> 1560<pre>~sentry(); 1561</pre> 1562<blockquote> 1563<p> 1564-17- If <tt>((os.flags() & ios_base::unitbuf) && !uncaught_exception())</tt> 1565is <tt>true</tt>, calls <tt>os.flush()</tt>. 1566</p> 1567 1568<p><ins> 1569<i>Throws:</i> Nothing. 1570</ins></p> 1571</blockquote> 1572</blockquote> 1573 1574 1575 1576 1577 1578<hr> 1579<h3><a name="408"></a>408. Is vector<reverse_iterator<char*> > forbidden?</h3> 1580<p><b>Section:</b> 24.2 [iterator.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 1581 <b>Submitter:</b> Nathan Myers <b>Opened:</b> 2003-06-03 <b>Last modified:</b> 2009-11-03</p> 1582<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#iterator.requirements">active issues</a> in [iterator.requirements].</p> 1583<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#iterator.requirements">issues</a> in [iterator.requirements].</p> 1584<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 1585<p><b>Discussion:</b></p> 1586<p> 1587I've been discussing iterator semantics with Dave Abrahams, and a 1588surprise has popped up. I don't think this has been discussed before. 1589</p> 1590 1591<p> 1592X [iterator.concepts] says that the only operation that can be performed on "singular" 1593iterator values is to assign a non-singular value to them. (It 1594doesn't say they can be destroyed, and that's probably a defect.) 1595Some implementations have taken this to imply that there is no need 1596to initialize the data member of a reverse_iterator<> in the default 1597constructor. As a result, code like 1598</p> 1599<blockquote><pre> std::vector<std::reverse_iterator<char*> > v(7); 1600 v.reserve(1000); 1601</pre></blockquote> 1602<p> 1603invokes undefined behavior, because it must default-initialize the 1604vector elements, and then copy them to other storage. Of course many 1605other vector operations on these adapters are also left undefined, 1606and which those are is not reliably deducible from the standard. 1607</p> 1608 1609<p> 1610I don't think that 24.1 was meant to make standard-library iterator 1611types unsafe. Rather, it was meant to restrict what operations may 1612be performed by functions which take general user- and standard 1613iterators as arguments, so that raw pointers would qualify as 1614iterators. However, this is not clear in the text, others have come 1615to the opposite conclusion. 1616</p> 1617 1618<p> 1619One question is whether the standard iterator adaptors have defined 1620copy semantics. Another is whether they have defined destructor 1621semantics: is 1622</p> 1623<blockquote><pre> { std::vector<std::reverse_iterator<char*> > v(7); } 1624</pre></blockquote> 1625<p> 1626undefined too? 1627</p> 1628 1629<p> 1630Note this is not a question of whether algorithms are allowed to 1631rely on copy semantics for arbitrary iterators, just whether the 1632types we actually supply support those operations. I believe the 1633resolution must be expressed in terms of the semantics of the 1634adapter's argument type. It should make clear that, e.g., the 1635reverse_iterator<T> constructor is actually required to execute 1636T(), and so copying is defined if the result of T() is copyable. 1637</p> 1638 1639<p> 1640Issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#235">235</a>, which defines reverse_iterator's default 1641constructor more precisely, has some relevance to this issue. 1642However, it is not the whole story. 1643</p> 1644 1645<p> 1646The issue was whether 1647</p> 1648<blockquote><pre> reverse_iterator() { } 1649</pre></blockquote> 1650<p> 1651is allowed, vs. 1652</p> 1653<blockquote><pre> reverse_iterator() : current() { } 1654</pre></blockquote> 1655 1656<p> 1657The difference is when T is char*, where the first leaves the member 1658uninitialized, and possibly equal to an existing pointer value, or 1659(on some targets) may result in a hardware trap when copied. 1660</p> 1661 1662<p> 16638.5 paragraph 5 seems to make clear that the second is required to 1664satisfy DR <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#235">235</a>, at least for non-class Iterator argument 1665types. 1666</p> 1667 1668<p> 1669But that only takes care of reverse_iterator, and doesn't establish 1670a policy for all iterators. (The reverse iterator adapter was just 1671an example.) In particular, does my function 1672</p> 1673<blockquote><pre> template <typename Iterator> 1674 void f() { std::vector<Iterator> v(7); } 1675</pre></blockquote> 1676<p> 1677evoke undefined behavior for some conforming iterator definitions? 1678I think it does, now, because vector<> will destroy those singular 1679iterator values, and that's explicitly disallowed. 1680</p> 1681 1682<p> 168324.1 shouldn't give blanket permission to copy all singular iterators, 1684because then pointers wouldn't qualify as iterators. However, it 1685should allow copying of that subset of singular iterator values that 1686are default-initialized, and it should explicitly allow destroying any 1687iterator value, singular or not, default-initialized or not. 1688</p> 1689 1690<p>Related issues: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#407">407</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1012">1012</a></p> 1691<p><i>[ 1692We don't want to require all singular iterators to be copyable, 1693because that is not the case for pointers. However, default 1694construction may be a special case. Issue: is it really default 1695construction we want to talk about, or is it something like value 1696initialization? We need to check with core to see whether default 1697constructed pointers are required to be copyable; if not, it would be 1698wrong to impose so strict a requirement for iterators. 1699]</i></p> 1700 1701 1702<p><i>[ 17032009-05-10 Alisdair provided wording. 1704]</i></p> 1705 1706 1707<blockquote> 1708The comments regarding destroying singular iterators have already been 1709resolved. That just leaves copying (with moving implied). 1710</blockquote> 1711 1712<p><i>[ 17132009-07 Frankfurt 1714]</i></p> 1715 1716 1717<blockquote> 1718<p> 1719This is related to LWG <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1012">1012</a>. 1720</p> 1721<p> 1722Note that there is a bug in the proposed resolution to LWG <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1012">1012</a>. The 1723change to [reverse.iter.con] should be modified so that the word 1724"default" in the second sentence of the Effects clause is replaced by 1725"value." 1726</p> 1727<p> 1728We believe that the proposed fix to LWG <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1012">1012</a> (now corrected) is 1729sufficient to solve the problem for reverse_iterator. However, Alisdair 1730pointed out that LWG <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1012">1012</a> does not solve the general problem for authors 1731of iterator adaptors. 1732</p> 1733<p> 1734There are some problems with the proposed resolution. The phrase "safely 1735copyable" is not a term of art. Also, it mentions a 1736DefaultConstructible? concept. 1737</p> 1738<p> 1739Move to Review after Alisdair updates the wording. 1740</p> 1741</blockquote> 1742 1743<p><i>[ 17442009-07-31 Alisdair revised wording: 1745]</i></p> 1746 1747 1748<p><i>[ 17492009-08-17 Alisdair and Daniel collaborate on slightly revised wording. 1750This issue depends upon <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#724">724</a> 1751]</i></p> 1752 1753 1754<p><i>[ 17552009-10-14 Daniel adds: 1756]</i></p> 1757 1758 1759<blockquote> 1760There is a clear dependency on <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1213">1213</a>, because the term "singular", 1761which is used as part of the resolution, is not properly defined yet. 1762</blockquote> 1763 1764<p><i>[ 17652009-10 Santa Cruz: 1766]</i></p> 1767 1768 1769<blockquote> 1770Moved to Open. Alisdair will provide improved wording to make 1771this have "value semantics" and otherwise behave like a valid iterator. 1772</blockquote> 1773 1774 1775 1776<p><b>Proposed resolution:</b></p> 1777<p> 1778Add a new paragrpah to Iterator concepts 24.2 [iterator.requirements] after para 5 (the one describing 1779singular iterators) 1780</p> 1781<blockquote> 1782<p> 1783Just as a regular pointer to an array guarantees that there is a pointer 1784value pointing past the last element of the array, so for any iterator 1785type there is an iterator value that points past the last element of a 1786corresponding container. These values are called <i>past-the-end</i> values. 1787Values of an iterator <tt>i</tt> for which the expression <tt>*i</tt> is defined are called 1788<i>dereferenceable</i>. The library never assumes that past-the-end values are 1789dereferenceable. Iterators can also have singular values that are not 1790associated with any container. [<i>Example:</i> After the declaration of an 1791uninitialized pointer <tt>x</tt> (as with <tt>int* x;</tt>), <tt>x</tt> must always be assumed to 1792have a singular value of a pointer. — <i>end example</i>] Results of most 1793expressions are undefined for singular values; the only exceptions are 1794destroying an iterator that holds a singular value and the assignment of 1795a non-singular value to an iterator that holds a singular value. In this 1796case the singular value is overwritten the same way as any other value. 1797Dereferenceable values are always non-singular. 1798</p> 1799<p><ins> 1800After value-initialization, any iterator that satisfies the 1801<tt>DefaultConstructible</tt> requirements ([defaultconstructible]) shall not introduce undefined behaviour 1802when used <ins>as</ins> the 1803source of a copy or move operation, even if it would 1804otherwise be singular. [<i>Note:</i> This guarantee is not offered for 1805default-initialization (8.5 [dcl.init]), although the distinction only 1806matters for types with trivial default constructors such as pointers. — 1807<i>end note</i>] 1808</ins></p> 1809 1810 1811</blockquote> 1812 1813 1814 1815 1816 1817 1818<hr> 1819<h3><a name="427"></a>427. stage 2 and rationale of DR 221</h3> 1820<p><b>Section:</b> 22.4.2.1.2 [facet.num.get.virtuals] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 1821 <b>Submitter:</b> Martin Sebor <b>Opened:</b> 2003-09-18 <b>Last modified:</b> 2009-10-26</p> 1822<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#facet.num.get.virtuals">active issues</a> in [facet.num.get.virtuals].</p> 1823<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#facet.num.get.virtuals">issues</a> in [facet.num.get.virtuals].</p> 1824<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 1825<p><b>Discussion:</b></p> 1826<p> 1827The requirements specified in Stage 2 and reiterated in the rationale 1828of DR 221 (and echoed again in DR 303) specify that num_get<charT>:: 1829do_get() compares characters on the stream against the widened elements 1830of "012...abc...ABCX+-" 1831</p> 1832 1833<p> 1834An implementation is required to allow programs to instantiate the num_get 1835template on any charT that satisfies the requirements on a user-defined 1836character type. These requirements do not include the ability of the 1837character type to be equality comparable (the char_traits template must 1838be used to perform tests for equality). Hence, the num_get template cannot 1839be implemented to support any arbitrary character type. The num_get template 1840must either make the assumption that the character type is equality-comparable 1841(as some popular implementations do), or it may use char_traits<charT> to do 1842the comparisons (some other popular implementations do that). This diversity 1843of approaches makes it difficult to write portable programs that attempt to 1844instantiate the num_get template on user-defined types. 1845</p> 1846 1847<p><i>[Kona: the heart of the problem is that we're theoretically 1848 supposed to use traits classes for all fundamental character 1849 operations like assignment and comparison, but facets don't have 1850 traits parameters. This is a fundamental design flaw and it 1851 appears all over the place, not just in this one place. It's not 1852 clear what the correct solution is, but a thorough review of facets 1853 and traits is in order. The LWG considered and rejected the 1854 possibility of changing numeric facets to use narrowing instead of 1855 widening. This may be a good idea for other reasons (see issue 1856 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#459">459</a>), but it doesn't solve the problem raised by this 1857 issue. Whether we use widen or narrow the <tt>num_get</tt> facet 1858 still has no idea which traits class the user wants to use for 1859 the comparison, because only streams, not facets, are passed traits 1860 classes. The standard does not require that two different 1861 traits classes with the same <tt>char_type</tt> must necessarily 1862 have the same behavior.]</i></p> 1863 1864 1865<p>Informally, one possibility: require that some of the basic 1866character operations, such as <tt>eq</tt>, <tt>lt</tt>, 1867and <tt>assign</tt>, must behave the same way for all traits classes 1868with the same <tt>char_type</tt>. If we accept that limitation on 1869traits classes, then the facet could reasonably be required to 1870use <tt>char_traits<charT></tt>.</p> 1871 1872<p><i>[ 18732009-07 Frankfurt 1874]</i></p> 1875 1876 1877<blockquote> 1878<p> 1879There was general agreement that the standard only needs to specify the 1880behavior when the character type is char or wchar_t. 1881</p> 1882<p> 1883Beman: we don't need to worry about C++1x because there is a non-zero 1884possibility that we would have a replacement facility for iostreams that 1885would solve these problems. 1886</p> 1887<p> 1888We need to change the following sentence in [locale.category], paragraph 18896 to specify that C is char and wchar_t: 1890</p> 1891<p> 1892"A template formal parameter with name C represents the set of all 1893possible specializations on a parameter that satisfies the requirements 1894for a character on which any member of the iostream components can be 1895instantiated." 1896</p> 1897<p> 1898We also need to specify in 27 that the basic character operations, such 1899as eq, lt, and assign use std::char_traits. 1900</p> 1901<p> 1902Daniel volunteered to provide wording. 1903</p> 1904</blockquote> 1905 1906<p><i>[ 19072009-09-19 Daniel provided wording. 1908]</i></p> 1909 1910 1911<p><i>[ 19122009-10 Santa Cruz: 1913]</i></p> 1914 1915 1916<blockquote> 1917Leave as Open. Alisdair and/or Tom will provide wording based on discussions. 1918We want to clearly state that streams and locales work just on <tt>char</tt> 1919and <tt>wchar_t</tt> (except where otherwise specified). 1920</blockquote> 1921 1922 1923 1924<p><b>Proposed resolution:</b></p> 1925<ol> 1926<li> 1927<p> 1928Change 22.3.1.1.1 [locale.category]/6: 1929</p> 1930 1931<blockquote> 1932[..] A template formal parameter with name <tt>C</tt> represents the set of all possible 1933specializations on a <ins><tt>char</tt> or <tt>wchar_t</tt></ins> parameter<del> that satisfies 1934the requirements for a character on which any of the iostream components 1935can be instantiated</del>. [..] 1936</blockquote> 1937</li> 1938 1939<li> 1940<p> 1941Add the following sentence to the end of 22.4.2 [category.numeric]/2: 1942</p> 1943 1944<blockquote> 1945[..] These specializations refer to [..], and also for the <tt>ctype<></tt> facet to 1946perform character classification. <ins>Implementations are encouraged 1947but not required to use the <tt>char_traits<charT></tt> functions for all 1948comparisons and assignments of characters of type <tt>charT</tt> that do 1949not belong to the set of required specializations.</ins> 1950</blockquote> 1951</li> 1952 1953<li> 1954<p> 1955Change 22.4.2.1.2 [facet.num.get.virtuals]/3: 1956</p> 1957 1958<blockquote> 1959<p> 1960Stage 2: If <tt>in==end</tt> then stage 2 terminates. Otherwise a <tt>charT</tt> is taken 1961from <tt>in</tt> and local variables are initialized as if by 1962</p> 1963 1964<blockquote><pre>char_type ct = *in; 1965<ins>using tr = char_traits<char_type>; 1966const char_type* pos = tr::find(atoms, sizeof(src) - 1, ct);</ins> 1967char c = src[<del>find(atoms, atoms + sizeof(src) - 1, ct) - atoms</del> 1968 <ins>pos ? pos - atoms : sizeof(src) - 1</ins>]; 1969if (<ins>tr::eq(ct, </ins><del>ct == </del>use_facet<numpunct<charT>(loc).decimal_point()<ins>)</ins>) 1970 c = '.'; 1971bool discard = 1972 <ins>tr::eq(ct, </ins><del>ct == </del>use_facet<numpunct<charT>(loc).thousands_sep()<ins>)</ins> 1973 && use_facet<numpunct<charT> >(loc).grouping().length() != 0; 1974</pre></blockquote> 1975 1976<p> 1977where the values <tt>src</tt> and <tt>atoms</tt> are defined as if by: [..] 1978</p> 1979</blockquote> 1980 1981<p> 1982[Remark of the author: I considered to replace the initialization 1983"<tt>char_type ct = *in;</tt>" 1984by the sequence "<tt>char_type ct; tr::assign(ct, *in);</tt>", but decided 1985against it, because 1986it is a copy-initialization context, not an assignment] 1987</p> 1988</li> 1989 1990<li> 1991<p> 1992Add the following sentence to the end of 22.4.5 [category.time]/1: 1993</p> 1994 1995<blockquote> 1996[..] Their members use [..] , to determine formatting details. 1997<ins>Implementations are encouraged but not required to use the 1998<tt>char_traits<charT></tt> functions for all comparisons and assignments 1999of characters of type <tt>charT</tt> that do 2000not belong to the set of required specializations.</ins> 2001</blockquote> 2002</li> 2003 2004<li> 2005<p> 2006Change 22.4.5.1.1 [locale.time.get.members]/8 bullet 4: 2007</p> 2008 2009<ul> 2010<li> 2011<del>The next element of <tt>fmt</tt> is equal to <tt>'%'</tt></del> <ins>For the next element <tt>c</tt> 2012of <tt>fmt char_traits<char_type>::eq(c, use_facet<ctype<char_type>>(f.getloc()).widen('%')) == true</tt></ins>, 2013[..] 2014</li> 2015</ul> 2016</li> 2017 2018<li> 2019<p> 2020Add the following sentence to the end of 22.4.6 [category.monetary]/2: 2021</p> 2022 2023<blockquote> 2024Their members use [..] to determine formatting details. 2025<ins>Implementations are encouraged but not required to use the 2026<tt>char_traits<charT></tt> functions for all comparisons and assignments 2027of characters of type <tt>charT</tt> that do 2028not belong to the set of required specializations.</ins> 2029</blockquote> 2030</li> 2031 2032<li> 2033<p> 2034Change 22.4.6.1.2 [locale.money.get.virtuals]/4: 2035</p> 2036 2037<blockquote> 2038<p> 2039[..] The value <tt>units</tt> is produced as if by: 2040</p> 2041 2042<blockquote><pre>for (int i = 0; i < n; ++i) 2043 buf2[i] = src[<ins>char_traits<charT>::</ins>find(atoms, <del>atoms+</del>sizeof(src), buf1[i]) - atoms]; 2044buf2[n] = 0; 2045sscanf(buf2, "%Lf", &units); 2046</pre></blockquote> 2047</blockquote> 2048</li> 2049 2050<li> 2051<p> 2052Change 22.4.6.2.2 [locale.money.put.virtuals]/1: 2053</p> 2054 2055<blockquote> 2056[..] for character buffers <tt>buf1</tt> and <tt>buf2</tt>. If <ins>for</ins> the first 2057character <ins><tt>c</tt></ins> 2058in <tt>digits</tt> or <tt>buf2</tt> <del>is equal to 2059<tt>ct.widen('-')</tt></del><ins><tt>char_traits<charT>::eq(c, 2060ct.widen('-')) == true</tt></ins>, [..] 2061</blockquote> 2062</li> 2063 2064<li> 2065<p> 2066Add a footnote to the first sentence of 27.7.1.2.2 [istream.formatted.arithmetic]/1: 2067</p> 2068 2069<blockquote> 2070<p> 2071As in the case of the inserters, these extractors depend on the locale's 2072<tt>num_get<></tt> (22.4.2.1) object to perform parsing the input stream 2073data.<ins><sup>(footnote)</sup></ins> [..] 2074</p> 2075 2076<p> 2077<ins> 2078<sup>footnote)</sup> If the traits of the input stream has different semantics for <tt>lt()</tt>, 2079<tt>eq()</tt>, and <tt>assign()</tt> than <tt>char_traits<char_type></tt>, this may give surprising 2080results. 2081</ins> 2082</p> 2083</blockquote> 2084</li> 2085 2086<li> 2087<p> 2088Add a footnote to the second sentence of 27.7.2.6.2 [ostream.inserters.arithmetic]/1: 2089</p> 2090 2091<blockquote> 2092<p> 2093<i>Effects:</i> The classes <tt>num_get<></tt> and 2094<tt>num_put<></tt> handle locale-dependent numeric formatting and 2095parsing. These inserter functions use the imbued locale value to perform 2096numeric formatting.<ins><sup>(footnote)</sup></ins> [..] 2097</p> 2098 2099<p> 2100<ins> 2101<sup>footnote)</sup> If the traits of the output stream has different semantics for <tt>lt()</tt>, 2102<tt>eq()</tt>, and <tt>assign()</tt> than <tt>char_traits<char_type></tt>, this may give surprising 2103results. 2104</ins> 2105</p> 2106</blockquote> 2107</li> 2108 2109<li> 2110<p> 2111Add a footnote after the first sentence of 27.7.4 [ext.manip]/4: 2112</p> 2113 2114<blockquote> 2115<p> 2116<i>Returns:</i> An object of unspecified type such that if in is an object of type 2117<tt>basic_istream<charT, traits></tt> then the expression <tt>in >> get_money(mon, intl)</tt> 2118behaves as if it called <tt>f(in, mon, intl)</tt>, where the function <tt>f</tt> is defined 2119as:<ins><sup>(footnote)</sup></ins> [..] 2120</p> 2121 2122<p> 2123<ins> 2124<sup>footnote)</sup> If the traits of the input stream has different semantics for <tt>lt()</tt>, 2125<tt>eq()</tt>, and <tt>assign()</tt> than <tt>char_traits<char_type></tt>, this may give surprising 2126results. 2127</ins> 2128</p> 2129</blockquote> 2130</li> 2131 2132<li> 2133<p> 2134Add a footnote after the first sentence of 27.7.4 [ext.manip]/5: 2135</p> 2136 2137<blockquote> 2138<p> 2139<i>Returns:</i> An object of unspecified type such that if <tt>out</tt> is an object of type 2140<tt>basic_ostream<charT, traits></tt> then the expression <tt>out << put_money(mon, intl)</tt> 2141behaves as a formatted input function that calls <tt>f(out, mon, intl)</tt>, where the 2142function <tt>f</tt> is defined as:<ins><sup>(footnote)</sup></ins> [..] 2143</p> 2144 2145<p> 2146<ins> 2147<sup>footnote)</sup> If the traits of the output stream has different semantics for <tt>lt()</tt>, 2148<tt>eq()</tt>, and <tt>assign()</tt> than <tt>char_traits<char_type></tt>, this may give surprising 2149results. 2150</ins> 2151</p> 2152</blockquote> 2153</li> 2154 2155<li> 2156<p> 215713) Add a footnote after the first sentence of 27.7.4 [ext.manip]/8: 2158</p> 2159 2160<blockquote> 2161<p> 2162<i>Returns:</i> An object of unspecified type such that if <tt>in</tt> is an 2163object of type b<tt>asic_istream<charT, traits></tt> then the expression 2164<tt>in >>get_time(tmb, fmt)</tt> behaves as if it called <tt>f(in, tmb, fmt)</tt>, 2165where the function <tt>f</tt> is defined as:<ins><sup>(footnote)</sup></ins> [..] 2166</p> 2167 2168<p> 2169<ins> 2170<sup>footnote)</sup> If the traits of the input stream has different semantics for <tt>lt()</tt>, 2171<tt>eq()</tt>, and <tt>assign()</tt> than <tt>char_traits<char_type></tt>, this may give surprising 2172results. 2173</ins> 2174</p> 2175</blockquote> 2176</li> 2177 2178<li> 2179<p> 2180Add a footnote after the first sentence of 27.7.4 [ext.manip]/10: 2181</p> 2182 2183<blockquote> 2184<p> 2185Returns: An object of unspecified type such that if <tt>out</tt> is an object of type 2186<tt>basic_ostream<charT, traits></tt> then the expression <tt>out <<put_time(tmb, fmt)</tt> 2187behaves as if it called <tt>f(out, tmb, fmt)</tt>, where the function <tt>f</tt> is defined 2188as:<ins><sup>(footnote)</sup></ins> [..] 2189</p> 2190 2191<p> 2192<ins> 2193<sup>footnote)</sup> If the traits of the output stream has different semantics for <tt>lt()</tt>, 2194<tt>eq()</tt>, and <tt>assign()</tt> than <tt>char_traits<char_type></tt>, this may give surprising 2195results. 2196</ins> 2197</p> 2198</blockquote> 2199</li> 2200</ol> 2201 2202 2203 2204 2205 2206<hr> 2207<h3><a name="430"></a>430. valarray subset operations</h3> 2208<p><b>Section:</b> 26.6.2.4 [valarray.sub] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 2209 <b>Submitter:</b> Martin Sebor <b>Opened:</b> 2003-09-18 <b>Last modified:</b> 2009-11-04</p> 2210<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 2211<p><b>Discussion:</b></p> 2212<p> 2213The standard fails to specify the behavior of valarray::operator[](slice) 2214and other valarray subset operations when they are passed an "invalid" 2215slice object, i.e., either a slice that doesn't make sense at all (e.g., 2216slice (0, 1, 0) or one that doesn't specify a valid subset of the valarray 2217object (e.g., slice (2, 1, 1) for a valarray of size 1). 2218</p> 2219<p><i>[Kona: the LWG believes that invalid slices should invoke 2220 undefined behavior. Valarrays are supposed to be designed for high 2221 performance, so we don't want to require specific checking. We 2222 need wording to express this decision.]</i></p> 2223 2224 2225<p><i>[ 2226Bellevue: 2227]</i></p> 2228 2229 2230<blockquote> 2231Please note that the standard also fails to specify the behavior of 2232slice_array and gslice_array in the valid case. Bill Plauger will 2233endeavor to provide revised wording for slice_array and gslice_array. 2234</blockquote> 2235 2236<p><i>[ 2237post-Bellevue: Bill provided wording. 2238]</i></p> 2239 2240 2241<p><i>[ 22422009-07 Frankfurt 2243]</i></p> 2244 2245 2246<blockquote> 2247<p> 2248Move to Ready. 2249</p> 2250</blockquote> 2251 2252<p><i>[ 22532009-11-04 Pete opens: 2254]</i></p> 2255 2256 2257<blockquote> 2258The resolution to LWG issue 430 has not been applied --- there have been 2259changes to the underlying text, and the resolution needs to be reworked. 2260</blockquote> 2261 2262 2263 2264<p><b>Proposed resolution:</b></p> 2265<p> 2266Insert after 26.6.2.4 [valarray.sub], paragraph 1: 2267</p> 2268 2269<blockquote> 2270<p> 2271The member operator is overloaded to provide several ways to select 2272sequences 2273of elements from among those controlled by <tt>*this</tt>. The first group of five 2274member operators work in conjunction with various overloads of <tt>operator=</tt> 2275(and other assigning operators) to allow selective replacement (slicing) of 2276the controlled sequence. The selected elements must exist. 2277</p> 2278<p> 2279The first member operator selects element off. For example: 2280</p> 2281 2282<blockquote><pre>valarray<char> v0("abcdefghijklmnop", 16); 2283v0[3] = 'A'; 2284// v0 == valarray<char>("abcAefghijklmnop", 16) 2285</pre></blockquote> 2286 2287<p> 2288The second member operator selects those elements of the controlled sequence 2289designated by <tt>slicearr</tt>. For example: 2290</p> 2291 2292<blockquote><pre>valarray<char> v0("abcdefghijklmnop", 16); 2293valarray<char> v1("ABCDE", 5); 2294v0[slice(2, 5, 3)] = v1; 2295// v0 == valarray<char>("abAdeBghCjkDmnEp", 16) 2296</pre></blockquote> 2297 2298<p> 2299The third member operator selects those elements of the controlled sequence 2300designated by <tt>gslicearr</tt>. For example: 2301</p> 2302 2303<blockquote><pre>valarray<char> v0("abcdefghijklmnop", 16); 2304valarray<char> v1("ABCDEF", 6); 2305const size_t lv[] = {2, 3}; 2306const size_t dv[] = {7, 2}; 2307const valarray<size_t> len(lv, 2), str(dv, 2); 2308v0[gslice(3, len, str)] = v1; 2309// v0 == valarray<char>("abcAeBgCijDlEnFp", 16) 2310</pre></blockquote> 2311 2312<p> 2313The fourth member operator selects those elements of the controlled sequence 2314designated by <tt>boolarr</tt>. For example: 2315</p> 2316 2317<blockquote><pre>valarray<char> v0("abcdefghijklmnop", 16); 2318valarray<char> v1("ABC", 3); 2319const bool vb[] = {false, false, true, true, false, true}; 2320v0[valarray<bool>(vb, 6)] = v1; 2321// v0 == valarray<char>("abABeCghijklmnop", 16) 2322</pre></blockquote> 2323 2324<p> 2325The fifth member operator selects those elements of the controlled sequence 2326designated by indarr. For example: 2327</p> 2328 2329<blockquote><pre>valarray<char> v0("abcdefghijklmnop", 16); 2330valarray<char> v1("ABCDE", 5); 2331const size_t vi[] = {7, 5, 2, 3, 8}; 2332v0[valarray<size_t>(vi, 5)] = v1; 2333// v0 == valarray<char>("abCDeBgAEjklmnop", 16) 2334</pre></blockquote> 2335 2336<p> 2337The second group of five member operators each construct an object that 2338represents the value(s) selected. The selected elements must exist. 2339</p> 2340 2341<p> 2342The sixth member operator returns the value of element off. For example: 2343</p> 2344 2345<blockquote><pre>valarray<char> v0("abcdefghijklmnop", 16); 2346// v0[3] returns 'd' 2347</pre></blockquote> 2348 2349<p> 2350The seventh member operator returns an object of class <tt>valarray<Ty></tt> 2351containing those elements of the controlled sequence designated by <tt>slicearr</tt>. 2352For example: 2353</p> 2354 2355<blockquote><pre>valarray<char> v0("abcdefghijklmnop", 16); 2356// v0[slice(2, 5, 3)] returns valarray<char>("cfilo", 5) 2357</pre></blockquote> 2358 2359<p> 2360The eighth member operator selects those elements of the controlled sequence 2361designated by <tt>gslicearr</tt>. For example: 2362</p> 2363 2364<blockquote><pre>valarray<char> v0("abcdefghijklmnop", 16); 2365const size_t lv[] = {2, 3}; 2366const size_t dv[] = {7, 2}; 2367const valarray<size_t> len(lv, 2), str(dv, 2); 2368// v0[gslice(3, len, str)] returns 2369// valarray<char>("dfhkmo", 6) 2370</pre></blockquote> 2371 2372<p> 2373The ninth member operator selects those elements of the controlled sequence 2374designated by <tt>boolarr</tt>. For example: 2375</p> 2376 2377<blockquote><pre>valarray<char> v0("abcdefghijklmnop", 16); 2378const bool vb[] = {false, false, true, true, false, true}; 2379// v0[valarray<bool>(vb, 6)] returns 2380// valarray<char>("cdf", 3) 2381</pre></blockquote> 2382 2383<p> 2384The last member operator selects those elements of the controlled sequence 2385designated by <tt>indarr</tt>. For example: 2386</p> 2387 2388<blockquote><pre>valarray<char> v0("abcdefghijklmnop", 16); 2389const size_t vi[] = {7, 5, 2, 3, 8}; 2390// v0[valarray<size_t>(vi, 5)] returns 2391// valarray<char>("hfcdi", 5) 2392</pre></blockquote> 2393 2394</blockquote> 2395 2396 2397 2398 2399 2400<hr> 2401<h3><a name="446"></a>446. Iterator equality between different containers</h3> 2402<p><b>Section:</b> 24.2 [iterator.requirements], 23.2 [container.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 2403 <b>Submitter:</b> Andy Koenig <b>Opened:</b> 2003-12-16 <b>Last modified:</b> 2009-11-03</p> 2404<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#iterator.requirements">active issues</a> in [iterator.requirements].</p> 2405<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#iterator.requirements">issues</a> in [iterator.requirements].</p> 2406<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 2407<p><b>Discussion:</b></p> 2408<p> 2409What requirements does the standard place on equality comparisons between 2410iterators that refer to elements of different containers. For example, if 2411v1 and v2 are empty vectors, is v1.end() == v2.end() allowed to yield true? 2412Is it allowed to throw an exception? 2413</p> 2414 2415<p> 2416The standard appears to be silent on both questions. 2417</p> 2418<p><i>[Sydney: The intention is that comparing two iterators from 2419different containers is undefined, but it's not clear if we say that, 2420or even whether it's something we should be saying in clause 23 or in 2421clause 24. Intuitively we might want to say that equality is defined 2422only if one iterator is reachable from another, but figuring out how 2423to say it in any sensible way is a bit tricky: reachability is defined 2424in terms of equality, so we can't also define equality in terms of 2425reachability. 2426]</i></p> 2427 2428 2429<p><i>[ 24302009-07 Frankfurt 2431]</i></p> 2432 2433 2434<blockquote> 2435Daniel volunteered to work on this. 2436</blockquote> 2437 2438<p><i>[ 24392009-09-20 Daniel provided wording. 2440]</i></p> 2441 2442 2443<p><i>[ 24442009-10 Santa Cruz: 2445]</i></p> 2446 2447 2448<blockquote> 2449Leave as Open. Alisdair has volunteered to refine the wording. 2450</blockquote> 2451 2452 2453 2454<p><b>Proposed resolution:</b></p> 2455<p> 2456Insert a new paragraph between 24.2 [iterator.requirements]/7+8: 2457</p> 2458 2459<blockquote> 2460<p> 2461[..] The result of the application of functions in the library to invalid 2462ranges is undefined. 2463</p> 2464 2465<p><ins>The result of directly or indirectly evaluating any comparison function 2466or the binary - operator with two iterator values as arguments that 2467were obtained 2468from two different ranges <tt>r1</tt> and <tt>r2</tt> (including their past-the-end values) which 2469are not subranges of one common range is undefined, unless explicitly 2470described otherwise.</ins> 2471</p> 2472 2473</blockquote> 2474 2475 2476 2477 2478 2479 2480<hr> 2481<h3><a name="471"></a>471. result of what() implementation-defined</h3> 2482<p><b>Section:</b> 18.8.1 [exception] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 2483 <b>Submitter:</b> Martin Sebor <b>Opened:</b> 2004-06-28 <b>Last modified:</b> 2009-10-26</p> 2484<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 2485<p><b>Discussion:</b></p> 2486 2487<p>[lib.exception] specifies the following:</p> 2488<pre> exception (const exception&) throw(); 2489 exception& operator= (const exception&) throw(); 2490 2491 -4- Effects: Copies an exception object. 2492 -5- Notes: The effects of calling what() after assignment 2493 are implementation-defined. 2494</pre> 2495 2496<p> 2497First, does the Note only apply to the assignment operator? If so, 2498what are the effects of calling what() on a copy of an object? Is 2499the returned pointer supposed to point to an identical copy of 2500the NTBS returned by what() called on the original object or not? 2501</p> 2502 2503<p> 2504Second, is this Note intended to extend to all the derived classes 2505in section 19? I.e., does the standard provide any guarantee for 2506the effects of what() called on a copy of any of the derived class 2507described in section 19? 2508</p> 2509 2510<p> 2511Finally, if the answer to the first question is no, I believe it 2512constitutes a defect since throwing an exception object typically 2513implies invoking the copy ctor on the object. If the answer is yes, 2514then I believe the standard ought to be clarified to spell out 2515exactly what the effects are on the copy (i.e., after the copy 2516ctor was called). 2517</p> 2518 2519<p><i>[Redmond: Yes, this is fuzzy. The issue of derived classes is 2520 fuzzy too.]</i></p> 2521 2522 2523<p><i>[ 2524Batavia: Howard provided wording. 2525]</i></p> 2526 2527 2528<p><i>[ 2529Bellevue: 2530]</i></p> 2531 2532 2533<blockquote> 2534<p> 2535Eric concerned this is unimplementable, due to nothrow guarantees. 2536Suggested implementation would involve reference counting. 2537</p> 2538<p> 2539Is the implied reference counting subtle enough to call out a note on 2540implementation? Probably not. 2541</p> 2542<p> 2543If reference counting required, could we tighten specification further 2544to require same pointer value? Probably an overspecification, especially 2545if exception classes defer evalutation of final string to calls to 2546what(). 2547</p> 2548<p> 2549Remember issue moved open and not resolved at Batavia, but cannot 2550remember who objected to canvas a disenting opinion - please speak up if 2551you disagree while reading these minutes! 2552</p> 2553<p> 2554Move to Ready as we are accepting words unmodified. 2555</p> 2556</blockquote> 2557 2558<p><i>[ 2559Sophia Antipolis: 2560]</i></p> 2561 2562 2563<blockquote> 2564The issue was pulled from Ready. It needs to make clear that only homogenous copying 2565is intended to be supported, not coping from a derived to a base. 2566</blockquote> 2567 2568<p><i>[ 2569Batavia (2009-05): 2570]</i></p> 2571 2572<blockquote> 2573<p> 2574Howard supplied the following replacement wording 2575for paragraph 7 of the proposed resolution: 2576</p> 2577<blockquote> 2578<ins>-7- <i>Postcondition:</i> <tt>what()</tt> shall return the same NTBS 2579 as would be obtained by using <tt>static_cast</tt> 2580 to cast the rhs to the same types as the lhs 2581 and then calling <tt>what()</tt> on that possibly sliced object.</ins> 2582</blockquote> 2583<p> 2584Pete asks what "the same NTBS" means. 2585</p> 2586</blockquote> 2587 2588<p><i>[ 25892009-07-30 Niels adds: 2590]</i></p> 2591 2592 2593<blockquote> 2594Further discussion in the thread starting with c++std-lib-24512. 2595</blockquote> 2596 2597<p><i>[ 25982009-09-24 Niels provided updated wording: 2599]</i></p> 2600 2601 2602<blockquote> 2603<p> 2604I think the resolution should at least guarantee 2605that the result of <tt>what()</tt> is independent of whether the compiler does 2606copy-elision. And for any class derived from <tt>std::excepion</tt> that has a 2607constructor that allows specifying a <tt>what_arg</tt>, it should make sure that 2608the text of a user-provided <tt>what_arg</tt> is preserved, when the object is 2609copied. Note that all the implementations I've tested already appear to 2610satisfy the proposed resolution, including MSVC 2008 SP1, Apache 2611stdcxx-4.2.1, GCC 4.1.2, GCC 4.3.2, and CodeGear C++ 6.13. 2612</p> 2613<p> 2614The proposed resolution was updated with help from Daniel Kr�gler; 2615the update aims to clarify that the proposed postcondition only 2616applies to homogeneous copying. 2617</p> 2618</blockquote> 2619 2620<p><i>[ 26212009-10 Santa Cruz: 2622]</i></p> 2623 2624 2625<blockquote> 2626Moved to Ready after inserting "publicly accessible" in two places. 2627</blockquote> 2628 2629 2630 2631<p><b>Proposed resolution:</b></p> 2632 2633<p> 2634Change 18.8.1 [exception] to: 2635</p> 2636 2637<blockquote> 2638<p> 2639-1- The class <tt>exception</tt> defines the base class for the types of 2640objects thrown as exceptions by C++ standard library components, and 2641certain expressions, to report errors detected during program execution. 2642</p> 2643<p><ins> 2644Each standard library class <tt>T</tt> that derives from class 2645<tt>exception</tt> shall have a publicly accessible copy constructor and a publicly accessible copy assignment 2646operator that do not exit with an exception. These member functions 2647shall preserve the following postcondition: If two objects <i>lhs</i> 2648and <i>rhs</i> both have dynamic type <tt>T</tt>, and <i>lhs</i> is a 2649copy of <i>rhs</i>, then <tt>strcmp(<i>lhs</i>.what(), 2650<i>rhs</i>.what()) == 0</tt>. 2651</ins></p> 2652<p> 2653 ... 2654</p> 2655 2656<pre>exception(const exception& <ins>rhs</ins>) throw(); 2657exception& operator=(const exception& <ins>rhs</ins>) throw();</pre> 2658 2659<blockquote> 2660<p> 2661-4- <i>Effects:</i> Copies an exception object. 2662</p> 2663<p> 2664<del> -5- <i>Remarks:</i> The effects of calling <tt>what()</tt> after assignment 2665are implementation-defined.</del> 2666</p> 2667<p> 2668<ins>-5- <i>Postcondition:</i> 2669 If <tt>*this</tt> 2670 and <i>rhs</i> both have dynamic type <tt>exception</tt> 2671 then <tt>strcmp(what(), <i>rhs</i>.what()) == 0</tt>.</ins> 2672</p> 2673 2674</blockquote> 2675 2676</blockquote> 2677 2678 2679 2680 2681 2682<hr> 2683<h3><a name="473"></a>473. underspecified ctype calls</h3> 2684<p><b>Section:</b> 22.4.1.1 [locale.ctype] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 2685 <b>Submitter:</b> Martin Sebor <b>Opened:</b> 2004-07-01 <b>Last modified:</b> 2009-10-21</p> 2686<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 2687<p><b>Discussion:</b></p> 2688<p> 2689Most ctype member functions come in two forms: one that operates 2690on a single character at a time and another form that operates 2691on a range of characters. Both forms are typically described by 2692a single Effects and/or Returns clause. 2693</p> 2694<p> 2695The Returns clause of each of the single-character non-virtual forms 2696suggests that the function calls the corresponding single character 2697virtual function, and that the array form calls the corresponding 2698virtual array form. Neither of the two forms of each virtual member 2699function is required to be implemented in terms of the other. 2700</p> 2701<p> 2702There are three problems: 2703</p> 2704<p> 27051. One is that while the standard does suggest that each non-virtual 2706member function calls the corresponding form of the virtual function, 2707it doesn't actually explicitly require it. 2708</p> 2709<p> 2710Implementations that cache results from some of the virtual member 2711functions for some or all values of their arguments might want to 2712call the array form from the non-array form the first time to fill 2713the cache and avoid any or most subsequent virtual calls. Programs 2714that rely on each form of the virtual function being called from 2715the corresponding non-virtual function will see unexpected behavior 2716when using such implementations. 2717</p> 2718<p> 27192. The second problem is that either form of each of the virtual 2720functions can be overridden by a user-defined function in a derived 2721class to return a value that is different from the one produced by 2722the virtual function of the alternate form that has not been 2723overriden. 2724</p> 2725<p> 2726Thus, it might be possible for, say, ctype::widen(c) to return one 2727value, while for ctype::widen(&c, &c + 1, &wc) to set 2728wc to another value. This is almost certainly not intended. Both 2729forms of every function should be required to return the same result 2730for the same character, otherwise the same program using an 2731implementation that calls one form of the functions will behave 2732differently than when using another implementation that calls the 2733other form of the function "under the hood." 2734</p> 2735<p> 27363. The last problem is that the standard text fails to specify whether 2737one form of any of the virtual functions is permitted to be implemented 2738in terms of the other form or not, and if so, whether it is required 2739or permitted to call the overridden virtual function or not. 2740</p> 2741<p> 2742Thus, a program that overrides one of the virtual functions so that 2743it calls the other form which then calls the base member might end 2744up in an infinite loop if the called form of the base implementation 2745of the function in turn calls the other form. 2746</p> 2747<p> 2748Lillehammer: Part of this isn't a real problem. We already talk about 2749caching. 22.1.1/6 But part is a real problem. ctype virtuals may call 2750each other, so users don't know which ones to override to avoid avoid 2751infinite loops.</p> 2752 2753<p>This is a problem for all facet virtuals, not just ctype virtuals, 2754so we probably want a blanket statement in clause 22 for all 2755facets. The LWG is leaning toward a blanket prohibition, that a 2756facet's virtuals may never call each other. We might want to do that 2757in clause 27 too, for that matter. A review is necessary. Bill will 2758provide wording.</p> 2759 2760<p><i>[ 27612009-07 Frankfurt, Howard provided wording directed by consensus. 2762]</i></p> 2763 2764 2765<p><i>[ 27662009-10 Santa Cruz: 2767]</i></p> 2768 2769 2770<blockquote> 2771Move to Ready. 2772</blockquote> 2773 2774 2775 2776<p><b>Proposed resolution:</b></p> 2777<p> 2778Add paragraph 3 to 22.4 [locale.categories]: 2779</p> 2780 2781<blockquote><ins> 2782-3- Within this clause it is unspecified if one virtual function calls another 2783virtual function. 2784</ins></blockquote> 2785 2786 2787 2788<p><b>Rationale:</b></p> 2789<p> 2790We are explicitly not addressing bullet 2791item #2, thus giving implementors more latitude. Users will have to 2792override both virtual functions, not just one. 2793</p> 2794 2795 2796 2797 2798<hr> 2799<h3><a name="485"></a>485. output iterator insufficiently constrained</h3> 2800<p><b>Section:</b> 24.2.2 [output.iterators] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 2801 <b>Submitter:</b> Chris Jefferson <b>Opened:</b> 2004-10-13 <b>Last modified:</b> 2009-10-26</p> 2802<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#output.iterators">issues</a> in [output.iterators].</p> 2803<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 2804<p><b>Discussion:</b></p> 2805<p> 2806The note on 24.1.2 Output iterators insufficiently limits what can be 2807performed on output iterators. While it requires that each iterator is 2808progressed through only once and that each iterator is written to only 2809once, it does not require the following things:</p> 2810 2811<p>Note: Here it is assumed that x is an output iterator of type X which 2812has not yet been assigned to.</p> 2813 2814<p>a) That each value of the output iterator is written to: 2815The standard allows: 2816++x; ++x; ++x; 2817</p> 2818 2819<p> 2820b) That assignments to the output iterator are made in order 2821X a(x); ++a; *a=1; *x=2; is allowed 2822</p> 2823 2824<p> 2825c) Chains of output iterators cannot be constructed: 2826X a(x); ++a; X b(a); ++b; X c(b); ++c; is allowed, and under the current 2827wording (I believe) x,a,b,c could be written to in any order. 2828</p> 2829 2830<p>I do not believe this was the intension of the standard?</p> 2831<p><i>[Lillehammer: Real issue. There are lots of constraints we 2832 intended but didn't specify. Should be solved as part of iterator 2833 redesign.]</i></p> 2834 2835 2836<p><i>[ 28372009-07 Frankfurt 2838]</i></p> 2839 2840 2841<blockquote> 2842Bill provided wording according to consensus. 2843</blockquote> 2844 2845<p><i>[ 28462009-07-21 Alisdair requests change from Review to Open. See thread starting 2847with c++std-lib-24459 for discussion. 2848]</i></p> 2849 2850 2851<p><i>[ 28522009-10 Santa Cruz: 2853]</i></p> 2854 2855 2856<blockquote> 2857Modified wording. Set to Review. 2858</blockquote> 2859 2860<p><i>[ 28612009-10 Santa Cruz: 2862]</i></p> 2863 2864 2865<blockquote> 2866Move to Ready after looking at again in a larger group in Santa Cruz. 2867</blockquote> 2868 2869 2870 2871<p><b>Proposed resolution:</b></p> 2872<p> 2873Change Table 101 — Output iterator requirements in 24.2.2 [output.iterators]: 2874</p> 2875<blockquote> 2876<table border="1"> 2877<caption>Table 101 — Output iterator requirements</caption> 2878<tbody><tr> 2879<th>Expression</th> 2880<th>Return type</th> 2881<th>Operational semantics</th> 2882<th>Assertion/note pre-/post-condition</th> 2883</tr> 2884 2885<tr> 2886<td> 2887<tt>X(a)</tt> 2888</td> 2889<td> 2890 2891</td> 2892<td> 2893 2894</td> 2895<td> 2896<tt>a = t</tt> is equivalent to <tt>X(a) = t</tt>. note: a destructor is assumed. 2897</td> 2898</tr> 2899 2900<tr> 2901<td> 2902<tt>X u(a);</tt><br> 2903<tt>X u = a;</tt> 2904</td> 2905<td> 2906 2907</td> 2908<td> 2909 2910</td> 2911<td> 2912 2913</td> 2914</tr> 2915 2916<tr> 2917<td> 2918<tt>*r = o</tt> 2919</td> 2920<td> 2921result is not used 2922</td> 2923<td> 2924 2925</td> 2926<td> 2927<ins> 2928Post: <tt>r</tt> is not required to be dereferenceable. <tt>r</tt> is incrementable. 2929</ins> 2930</td> 2931</tr> 2932 2933<tr> 2934<td> 2935<tt>++r</tt> 2936</td> 2937<td> 2938<tt>X&</tt> 2939</td> 2940<td> 2941 2942</td> 2943<td> 2944<tt>&r == &++r</tt> 2945<ins> 2946Post: <tt>r</tt> is dereferenceable, unless otherwise specified. <tt>r</tt> is not required to be incrementable. 2947</ins> 2948</td> 2949</tr> 2950 2951<tr> 2952<td> 2953<tt>r++</tt> 2954</td> 2955<td> 2956convertible to <tt>const X&</tt> 2957</td> 2958<td> 2959<tt>{X tmp = r;<br>++r;<br>return tmp;}</tt> 2960</td> 2961<td> 2962<ins> 2963Post: <tt>r</tt> is dereferenceable, unless otherwise specified. <tt>r</tt> is not required to be incrementable. 2964</ins> 2965</td> 2966</tr> 2967 2968<tr> 2969<td> 2970<tt>*r++ = o;</tt> 2971</td> 2972<td> 2973result is not used 2974</td> 2975<td> 2976 2977</td> 2978<td> 2979 2980</td> 2981</tr> 2982 2983</tbody></table> 2984</blockquote> 2985 2986 2987 2988 2989 2990<hr> 2991<h3><a name="539"></a>539. partial_sum and adjacent_difference should mention requirements</h3> 2992<p><b>Section:</b> 26.7.3 [partial.sum] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 2993 <b>Submitter:</b> Marc Schoolderman <b>Opened:</b> 2006-02-06 <b>Last modified:</b> 2009-10-24</p> 2994<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 2995<p><b>Discussion:</b></p> 2996<p> 2997There are some problems in the definition of partial_sum and 2998adjacent_difference in 26.4 [lib.numeric.ops] 2999</p> 3000 3001<p> 3002Unlike <tt>accumulate</tt> and <tt>inner_product</tt>, these functions are not 3003parametrized on a "type T", instead, 26.4.3 [lib.partial.sum] simply 3004specifies the effects clause as; 3005</p> 3006 3007<blockquote><p> 3008Assigns to every element referred to by iterator <tt>i</tt> in the range 3009<tt>[result,result + (last - first))</tt> a value correspondingly equal to 3010</p> 3011<blockquote><pre>((...(* first + *( first + 1)) + ...) + *( first + ( i - result ))) 3012</pre></blockquote> 3013</blockquote> 3014 3015<p> 3016And similarly for BinaryOperation. Using just this definition, it seems 3017logical to expect that: 3018</p> 3019 3020 3021<blockquote><pre>char i_array[4] = { 100, 100, 100, 100 }; 3022int o_array[4]; 3023 3024std::partial_sum(i_array, i_array+4, o_array); 3025</pre></blockquote> 3026 3027<p> 3028Is equivalent to 3029</p> 3030 3031<blockquote><pre>int o_array[4] = { 100, 100+100, 100+100+100, 100+100+100+100 }; 3032</pre></blockquote> 3033 3034<p> 3035i.e. 100, 200, 300, 400, with addition happening in the <tt>result type</tt>, 3036<tt>int</tt>. 3037</p> 3038 3039<p> 3040Yet all implementations I have tested produce 100, -56, 44, -112, 3041because they are using an accumulator of the <tt>InputIterator</tt>'s 3042<tt>value_type</tt>, which in this case is <tt>char</tt>, not <tt>int</tt>. 3043</p> 3044 3045<p> 3046The issue becomes more noticeable when the result of the expression <tt>*i + 3047*(i+1)</tt> or <tt>binary_op(*i, *i-1)</tt> can't be converted to the 3048<tt>value_type</tt>. In a contrived example: 3049</p> 3050 3051<blockquote><pre>enum not_int { x = 1, y = 2 }; 3052... 3053not_int e_array[4] = { x, x, y, y }; 3054std::partial_sum(e_array, e_array+4, o_array); 3055</pre></blockquote> 3056 3057<p> 3058Is it the intent that the operations happen in the <tt>input type</tt>, or in 3059the <tt>result type</tt>? 3060</p> 3061 3062<p> 3063If the intent is that operations happen in the <tt>result type</tt>, something 3064like this should be added to the "Requires" clause of 26.4.3/4 3065[lib.partial.sum]: 3066</p> 3067 3068<blockquote><p> 3069The type of <tt>*i + *(i+1)</tt> or <tt>binary_op(*i, *(i+1))</tt> shall meet the 3070requirements of <tt>CopyConstructible</tt> (20.1.3) and <tt>Assignable</tt> 3071(23.1) types. 3072</p></blockquote> 3073 3074<p> 3075(As also required for <tt>T</tt> in 26.4.1 [lib.accumulate] and 26.4.2 3076[lib.inner.product].) 3077</p> 3078 3079<p> 3080The "auto initializer" feature proposed in 3081<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2005/n1894.pdf">N1894</a> 3082is not required to 3083implement <tt>partial_sum</tt> this way. The 'narrowing' behaviour can still be 3084obtained by using the <tt>std::plus<></tt> function object. 3085</p> 3086 3087<p> 3088If the intent is that operations happen in the <tt>input type</tt>, then 3089something like this should be added instead; 3090</p> 3091 3092<blockquote><p> 3093The type of *first shall meet the requirements of 3094<tt>CopyConstructible</tt> (20.1.3) and <tt>Assignable</tt> (23.1) types. 3095The result of <tt>*i + *(i+1)</tt> or <tt>binary_op(*i, *(i+1))</tt> shall be 3096convertible to this type. 3097</p></blockquote> 3098 3099<p> 3100The 'widening' behaviour can then be obtained by writing a custom proxy 3101iterator, which is somewhat involved. 3102</p> 3103 3104<p> 3105In both cases, the semantics should probably be clarified. 3106</p> 3107 3108<p> 310926.4.4 [lib.adjacent.difference] is similarly underspecified, although 3110all implementations seem to perform operations in the 'result' type: 3111</p> 3112 3113<blockquote><pre>unsigned char i_array[4] = { 4, 3, 2, 1 }; 3114int o_array[4]; 3115 3116std::adjacent_difference(i_array, i_array+4, o_array); 3117</pre></blockquote> 3118 3119<p> 3120o_array is 4, -1, -1, -1 as expected, not 4, 255, 255, 255. 3121</p> 3122 3123<p> 3124In any case, <tt>adjacent_difference</tt> doesn't mention the requirements on the 3125<tt>value_type</tt>; it can be brought in line with the rest of 26.4 3126[lib.numeric.ops] by adding the following to 26.4.4/2 3127[lib.adjacent.difference]: 3128</p> 3129 3130<blockquote><p> 3131The type of <tt>*first</tt> shall meet the requirements of 3132<tt>CopyConstructible</tt> (20.1.3) and <tt>Assignable</tt> (23.1) types." 3133</p></blockquote> 3134<p><i>[ 3135Berlin: Giving output iterator's value_types very controversial. Suggestion of 3136adding signatures to allow user to specify "accumulator". 3137]</i></p> 3138 3139 3140<p><i>[ 3141Bellevue: 3142]</i></p> 3143 3144 3145<blockquote> 3146The intent of the algorithms is to perform their calculations using the type of the input iterator. 3147Proposed wording provided. 3148</blockquote> 3149 3150<p><i>[ 3151Sophia Antipolis: 3152]</i></p> 3153 3154 3155<blockquote> 3156We did not agree that the proposed resolution was correct. For example, 3157when the arguments are types <tt>(float*, float*, double*)</tt>, the 3158highest-quality solution would use double as the type of the 3159accumulator. If the intent of the wording is to require that the type of 3160the accumulator must be the <tt>input_iterator</tt>'s <tt>value_type</tt>, the wording 3161should specify it. 3162</blockquote> 3163 3164<p><i>[ 31652009-05-09 Alisdair adds: 3166]</i></p> 3167 3168 3169<blockquote> 3170<p> 3171Now that we have the facility, the 'best' accumulator type could probably be 3172deduced as: 3173</p> 3174<blockquote><pre>std::common_type<InIter::value_type, OutIter::reference>::type 3175</pre></blockquote> 3176<p> 3177This type would then have additional requirements of constructability and 3178incrementability/assignability. 3179</p> 3180<p> 3181If this extracting an accumulator type from a pair/set of iterators (with 3182additional requirements on that type) is a problem for multiple functions, 3183it might be worth extracting into a SharedAccumulator concept or similar. 3184</p> 3185<p> 3186I'll go no further in writing up wording now, until the group gives a 3187clearer indication of preferred direction. 3188</p> 3189</blockquote> 3190 3191<p><i>[ 31922009-07 Frankfurt 3193]</i></p> 3194 3195 3196<blockquote> 3197The proposed resolution isn't quite right. For example, "the type of 3198*first" should be changed to "iterator::value_type" or similar. Daniel 3199volunteered to correct the wording. 3200</blockquote> 3201 3202<p><i>[ 32032009-07-29 Daniel corrected wording. 3204]</i></p> 3205 3206 3207<p><i>[ 32082009-10 Santa Cruz: 3209]</i></p> 3210 3211 3212<blockquote> 3213Move to Ready. 3214</blockquote> 3215 3216 3217 3218<p><b>Proposed resolution:</b></p> 3219 3220 3221 3222<ol> 3223<li> 3224<p> 3225Change 26.7.3 [partial.sum]/1 as indicated: 3226</p> 3227 3228<blockquote> 3229<p> 3230<i>Effects:</i> <ins>Let <tt>VT</tt> be <tt>InputIterator</tt>'s value type. For a nonempty range, 3231initializes an accumulator <tt>acc</tt> of type <tt>VT</tt> with <tt>*first</tt> and performs 3232<tt>*result = acc</tt>. For every iterator <tt>i</tt> in <tt>[first + 1, last)</tt> in order, <tt>acc</tt> is then 3233modified by <tt>acc = acc + *i</tt> or <tt>acc = binary_op(acc, *i)</tt> and is assigned 3234to <tt>*(result + (i - first))</tt>.</ins> <del>Assigns to every element referred to by 3235iterator <tt>i</tt> in the range <tt>[result,result + (last - first))</tt> a value 3236correspondingly 3237equal to</del> 3238</p> 3239 3240<blockquote><pre><del> 3241((...(*first + *(first + 1)) + ...) + *(first + (i - result))) 3242</del></pre></blockquote> 3243 3244<p><del> 3245or 3246</del></p> 3247 3248<blockquote><pre><del> 3249binary_op(binary_op(..., 3250 binary_op(*first, *(first + 1)),...), *(first + (i - result))) 3251</del></pre></blockquote> 3252</blockquote> 3253</li> 3254 3255<li> 3256<p> 3257Change 26.7.3 [partial.sum]/3 as indicated: 3258</p> 3259 3260<blockquote> 3261<i>Complexity:</i> Exactly <tt><ins>max(</ins>(last - first) - 1<ins>, 0)</ins></tt> 3262applications 3263of <tt><del>binary_op</del></tt><ins>the binary operation</ins>. 3264</blockquote> 3265</li> 3266 3267<li> 3268<p> 3269Change 26.7.3 [partial.sum]/4 as indicated: 3270</p> 3271 3272<blockquote> 3273<i>Requires:</i> <ins><tt>VT</tt> shall be constructible from the type of <tt>*first</tt>, the result of 3274<tt>acc + *i</tt> or <tt>binary_op(acc, *i)</tt> shall be implicitly convertible to <tt>VT</tt>, and 3275the result of the expression <tt>acc</tt> shall be writable to the <tt>result</tt> 3276output iterator.</ins> In the ranges <tt>[first,last]</tt> and 3277<tt>[result,result + (last - first)]</tt> [..] 3278</blockquote> 3279</li> 3280 3281<li> 3282<p> 3283Change 26.7.4 [adjacent.difference]/1 as indicated: 3284</p> 3285 3286<blockquote> 3287<p> 3288<i>Effects:</i> <ins>Let <tt>VT</tt> be <tt>InputIterator</tt>'s value type. For a nonempty range, 3289initializes an accumulator <tt>acc</tt> of type <tt>VT</tt> with <tt>*first</tt> and performs 3290<tt>*result = acc</tt>. For every iterator <tt>i</tt> in <tt>[first + 1, last)</tt> in order, 3291initializes a 3292value <tt>val</tt> of type <tt>VT</tt> with <tt>*i</tt>, assigns the result of <tt>val - acc</tt> or 3293<tt>binary_op(val, acc)</tt> 3294to <tt>*(result + (i - first))</tt> and modifies <tt>acc = std::move(val)</tt>.</ins> 3295<del>Assigns to every element referred to by iterator <tt>i</tt> in the range 3296<tt>[result + 1, 3297result + (last - first))</tt> a value correspondingly equal to</del> 3298</p> 3299 3300<blockquote><pre><del> 3301*(first + (i - result)) - *(first + (i - result) - 1) 3302</del></pre></blockquote> 3303 3304<p><del> 3305or 3306</del></p> 3307 3308<blockquote><pre><del> 3309binary_op(*(first + (i - result)), *(first + (i - result) - 1)). 3310</del></pre></blockquote> 3311 3312<p><del> 3313result gets the value of *first.</del> 3314</p> 3315</blockquote> 3316</li> 3317 3318<li> 3319<p> 3320Change 26.7.4 [adjacent.difference]/2 as indicated: 3321</p> 3322 3323<blockquote> 3324<i>Requires:</i> <ins><tt>VT</tt> shall be <tt>MoveAssignable</tt> ([moveassignable]) 3325and shall be 3326constructible from the type of <tt>*first</tt>. The result 3327of the expression <tt>acc</tt> and the result of the expression <tt>val - acc</tt> or 3328<tt>binary_op(val, acc)</tt> 3329shall be writable to the <tt>result</tt> output iterator.</ins> In the ranges 3330<tt>[first,last]</tt> [..] 3331</blockquote> 3332</li> 3333 3334<li> 3335<p> 3336Change 26.7.4 [adjacent.difference]/5 as indicated: 3337</p> 3338 3339<blockquote> 3340<i>Complexity:</i> Exactly <tt><ins>max(</ins>(last - first) - 1<ins>, 0)</ins></tt> 3341applications 3342of <del><tt>binary_op</tt></del><ins>the binary operation</ins>. 3343</blockquote> 3344</li> 3345</ol> 3346 3347 3348 3349 3350 3351 3352 3353 3354<hr> 3355<h3><a name="556"></a>556. is Compare a BinaryPredicate?</h3> 3356<p><b>Section:</b> 25.4 [alg.sorting] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Review">Review</a> 3357 <b>Submitter:</b> Martin Sebor <b>Opened:</b> 2006-02-05 <b>Last modified:</b> 2009-10-25</p> 3358<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#alg.sorting">issues</a> in [alg.sorting].</p> 3359<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Review">Review</a> status.</p> 3360<p><b>Discussion:</b></p> 3361<p> 3362In 25, p8 we allow BinaryPredicates to return a type that's convertible 3363to bool but need not actually be bool. That allows predicates to return 3364things like proxies and requires that implementations be careful about 3365what kinds of expressions they use the result of the predicate in (e.g., 3366the expression in if (!pred(a, b)) need not be well-formed since the 3367negation operator may be inaccessible or return a type that's not 3368convertible to bool). 3369</p> 3370<p> 3371Here's the text for reference: 3372</p> 3373<blockquote><p> 3374 ...if an algorithm takes BinaryPredicate binary_pred as its argument 3375 and first1 and first2 as its iterator arguments, it should work 3376 correctly in the construct if (binary_pred(*first1, first2)){...}. 3377</p></blockquote> 3378 3379<p> 3380In 25.3, p2 we require that the Compare function object return true 3381of false, which would seem to preclude such proxies. The relevant text 3382is here: 3383</p> 3384<blockquote><p> 3385 Compare is used as a function object which returns true if the first 3386 argument is less than the second, and false otherwise... 3387</p></blockquote> 3388 3389<p><i>[ 3390Portland: Jack to define "convertible to bool" such that short circuiting isn't 3391destroyed. 3392]</i></p> 3393 3394 3395<p><i>[ 33962009-07-28 Reopened by Alisdair. No longer solved by concepts. 3397]</i></p> 3398 3399 3400<p><i>[ 34012009-10 Santa Cruz: 3402]</i></p> 3403 3404 3405<blockquote> 3406Move to Review once wording received. Stefanus to send proposed wording. 3407</blockquote> 3408 3409<p><i>[ 34102009-10 Santa Cruz: 3411]</i></p> 3412 3413 3414<blockquote> 3415Move to Review once wording received. Stefanus to send proposed wording. 3416</blockquote> 3417 3418<p><i>[ 34192009-10-24 Stefanus supplied wording. 3420]</i></p> 3421 3422 3423<blockquote> 3424Move to Review once wording received. Stefanus to send proposed wording. 3425Current proposed wording proposed here: 3426<blockquote> 3427<p> 3428I think we could fix this by rewording 25.3, p2 to read somthing like: 3429</p> 3430<blockquote><p> 3431-2- <tt>Compare</tt> is <del>used as a function object which returns 3432<tt>true</tt> if the first argument</del> <ins>a <tt>BinaryPredicate</tt>. The 3433return value of the function call operator applied to an object of type 3434<tt>Compare</tt>, when converted to type <tt>bool</tt>, yields <tt>true</tt> 3435if the first argument of the call</ins> is less than the second, and 3436<tt>false</tt> otherwise. <tt>Compare <i>comp</i></tt> is used throughout for 3437algorithms assuming an ordering relation. It is assumed that <tt><i>comp</i></tt> 3438will not apply any non-constant function through the dereferenced iterator. 3439</p></blockquote> 3440</blockquote> 3441</blockquote> 3442 3443 3444 3445<p><b>Proposed resolution:</b></p> 3446<p> 3447Change 25.4 [alg.sorting] p2: 3448</p> 3449<blockquote> 3450<tt>Compare</tt> is used as a function object<ins>. The return value of 3451the function call operator applied to an object of type Compare, when 3452converted to type bool, yields true if the first argument of the 3453call</ins> <del>which returns <tt>true</tt> if the first argument</del> 3454is less than the second, and <tt>false</tt> otherwise. <tt>Compare 3455comp</tt> is used throughout for algorithms assuming an ordering 3456relation. It is assumed that <tt>comp</tt> will not apply any 3457non-constant function through the dereferenced iterator. 3458</blockquote> 3459 3460 3461<p><b>Rationale:</b></p> 3462<p><i>[ 3463San Francisco: 3464]</i></p> 3465 3466 3467<blockquote> 3468Solved by 3469(<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2774.pdf">N2774</a>). 3470</blockquote> 3471 3472 3473 3474 3475 3476 3477<hr> 3478<h3><a name="594"></a>594. Disadvantages of defining Swappable in terms of CopyConstructible and Assignable</h3> 3479<p><b>Section:</b> 20.2.1 [utility.arg.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 3480 <b>Submitter:</b> Niels Dekker <b>Opened:</b> 2006-11-02 <b>Last modified:</b> 2009-11-08</p> 3481<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#utility.arg.requirements">active issues</a> in [utility.arg.requirements].</p> 3482<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#utility.arg.requirements">issues</a> in [utility.arg.requirements].</p> 3483<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 3484<p><b>Discussion:</b></p> 3485<p> 3486It seems undesirable to define the Swappable requirement in terms of 3487CopyConstructible and Assignable requirements. And likewise, once the 3488MoveConstructible and MoveAssignable requirements (N1860) have made it 3489into the Working Draft, it seems undesirable to define the Swappable 3490requirement in terms of those requirements. Instead, it appears 3491preferable to have the Swappable requirement defined exclusively in 3492terms of the existence of an appropriate swap function. 3493</p> 3494<p> 3495Section 20.1.4 [lib.swappable] of the current Working Draft (N2009) 3496says: 3497</p> 3498<blockquote><p> 3499The Swappable requirement is met by satisfying one or more of the 3500following conditions:</p> 3501<ul> 3502<li> 3503T is Swappable if T satisfies the CopyConstructible requirements 3504(20.1.3) and the Assignable requirements (23.1); 3505</li> 3506<li> 3507T is Swappable if a namespace scope function named swap exists in the 3508same namespace as the definition of T, such that the expression 3509swap(t,u) is valid and has the semantics described in Table 33. 3510</li> 3511</ul> 3512</blockquote> 3513<p> 3514I can think of three disadvantages of this definition: 3515</p> 3516<ol> 3517<li> 3518<p> 3519If a client's type T satisfies the first condition (T is both 3520CopyConstructible and Assignable), the client cannot stop T from 3521satisfying the Swappable requirement without stopping T from 3522satisfying the first condition. 3523</p> 3524<p> 3525A client might want to stop T from satisfying the Swappable 3526requirement, because swapping by means of copy construction and 3527assignment might throw an exception, and she might find a throwing 3528swap unacceptable for her type. On the other hand, she might not feel 3529the need to fully implement her own swap function for this type. In 3530this case she would want to be able to simply prevent algorithms that 3531would swap objects of type T from being used, e.g., by declaring a 3532swap function for T, and leaving this function purposely undefined. 3533This would trigger a link error, if an attempt would be made to use 3534such an algorithm for this type. For most standard library 3535implementations, this practice would indeed have the effect of 3536stopping T from satisfying the Swappable requirement. 3537</p> 3538</li> 3539<li> 3540<p> 3541A client's type T that does not satisfy the first condition can not be 3542made Swappable by providing a specialization of std::swap for T. 3543</p> 3544<p> 3545While I'm aware about the fact that people have mixed feelings about 3546providing a specialization of std::swap, it is well-defined to do so. 3547It sounds rather counter-intuitive to say that T is not Swappable, if 3548it has a valid and semantically correct specialization of std::swap. 3549Also in practice, providing such a specialization will have the same 3550effect as satisfying the Swappable requirement. 3551</p> 3552</li> 3553<li> 3554<p> 3555For a client's type T that satisfies both conditions of the Swappable 3556requirement, it is not specified which of the two conditions prevails. 3557After reading section 20.1.4 [lib.swappable], one might wonder whether 3558objects of T will be swapped by doing copy construction and 3559assignments, or by calling the swap function of T. 3560</p> 3561<p> 3562I'm aware that the intention of the Draft is to prefer calling the 3563swap function of T over doing copy construction and assignments. Still 3564in my opinion, it would be better to make this clear in the wording of 3565the definition of Swappable. 3566</p> 3567</li> 3568</ol> 3569<p> 3570I would like to have the Swappable requirement defined in such a way 3571that the following code fragment will correctly swap two objects of a 3572type T, if and only if T is Swappable: 3573</p> 3574<pre> using std::swap; 3575 swap(t, u); // t and u are of type T. 3576</pre> 3577<p> 3578This is also the way Scott Meyers recommends calling a swap function, 3579in Effective C++, Third Edition, item 25. 3580</p> 3581<p> 3582Most aspects of this issue have been dealt with in a discussion on 3583comp.std.c++ about the Swappable requirement, from 13 September to 4 3584October 2006, including valuable input by David Abrahams, Pete Becker, 3585Greg Herlihy, Howard Hinnant and others. 3586</p> 3587 3588<p><i>[ 3589San Francisco: 3590]</i></p> 3591 3592 3593<blockquote> 3594Recommend NAD. Solved by 3595<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2774.pdf">N2774</a>. 3596</blockquote> 3597 3598<p><i>[ 35992009-07 Frankfurt 3600]</i></p> 3601 3602 3603<blockquote> 3604Moved to Open. Waiting for non-concepts draft. 3605</blockquote> 3606 3607<p><i>[ 36082009-11-08 Howard adds: 3609]</i></p> 3610 3611 3612<blockquote> 3613This issue is very closely related to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#742">742</a>. 3614</blockquote> 3615 3616 3617<p><b>Proposed resolution:</b></p> 3618<p> 3619Change section 20.1.4 [lib.swappable] as follows: 3620</p> 3621<blockquote><p> 3622The Swappable requirement is met by satisfying 3623<del>one or more of the following conditions:</del> 3624<ins>the following condition:</ins></p> 3625<ul> 3626 3627<li> 3628<del>T is Swappable if T satisfies the CopyConstructible requirements 3629(20.1.3) and the Assignable requirements (23.1);</del> 3630</li> 3631<li> 3632<del> 3633T is Swappable if a namespace scope function named swap exists in the 3634same namespace as the definition of T, such that the expression 3635swap(t,u) is valid and has the semantics described in Table 33. 3636</del> 3637T is Swappable if an unqualified function call swap(t,u) is valid 3638within the namespace std, and has the semantics described in Table 33. 3639</li> 3640</ul> 3641</blockquote> 3642 3643 3644 3645 3646 3647<hr> 3648<h3><a name="625"></a>625. mixed up <i>Effects</i> and <i>Returns</i> clauses</h3> 3649<p><b>Section:</b> 17 [library] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 3650 <b>Submitter:</b> Martin Sebor <b>Opened:</b> 2007-01-20 <b>Last modified:</b> 2009-10-20</p> 3651<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#library">active issues</a> in [library].</p> 3652<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#library">issues</a> in [library].</p> 3653<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 3654<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#895">895</a></p> 3655<p><b>Discussion:</b></p> 3656 <p> 3657 3658Many member functions of <code>basic_string</code> are overloaded, 3659with some of the overloads taking a <code>string</code> argument, 3660others <code>value_type*</code>, others <code>size_type</code>, and 3661others still <code>iterators</code>. Often, the requirements on one of 3662the overloads are expressed in the form of <i>Effects</i>, 3663<i>Throws</i>, and in the Working Paper 3664(<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2006/n2134.pdf">N2134</a>) 3665also <i>Remark</i> clauses, while those on the rest of the overloads 3666via a reference to this overload and using a <i>Returns</i> clause. 3667</p> 3668 3669<p> 3670The difference between the two forms of specification is that per 367117.5.1.4 [structure.specifications], p3, an <i>Effects</i> clause specifies 3672<i>"actions performed by the functions,"</i> i.e., its observable 3673effects, while a <i>Returns</i> clause is <i>"a description of the 3674return value(s) of a function"</i> that does not impose any 3675requirements on the function's observable effects. 3676</p> 3677 3678<p> 3679Since only <i>Notes</i> are explicitly defined to be informative and 3680all other paragraphs are explicitly defined to be normative, like 3681<i>Effects</i> and <i>Returns</i>, the new <i>Remark</i> clauses also 3682impose normative requirements. 3683</p> 3684 3685<p> 3686So by this strict reading of the standard there are some member 3687functions of <code>basic_string</code> that are required to throw an 3688exception under some conditions or use specific traits members while 3689many other otherwise equivalent overloads, while obliged to return the 3690same values, aren't required to follow the exact same requirements 3691with regards to the observable effects. 3692</p> 3693 3694<p> 3695Here's an example of this problem that was precipitated by the change 3696from informative Notes to normative <i>Remark</i>s (presumably made to 3697address <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#424">424</a>): 3698</p> 3699 3700<p> 3701In the Working Paper, <code>find(string, size_type)</code> contains a 3702<i>Remark</i> clause (which is just a <i>Note</i> in the current 3703standard) requiring it to use <code>traits::eq()</code>. 3704</p> 3705 3706<p> 3707<code>find(const charT *s, size_type pos)</code> is specified to 3708return <code>find(string(s), pos)</code> by a <i>Returns</i> clause 3709and so it is not required to use <code>traits::eq()</code>. However, 3710the Working Paper has replaced the original informative <i>Note</i> 3711about the function using <code>traits::length()</code> with a 3712normative requirement in the form of a <i>Remark</i>. Calling 3713<code>traits::length()</code> may be suboptimal, for example when the 3714argument is a very long array whose initial substring doesn't appear 3715anywhere in <code>*this</code>. 3716</p> 3717 3718<p> 3719Here's another similar example, one that existed even prior to the 3720introduction of <i>Remark</i>s: 3721</p> 3722 3723<p> 3724<code> insert(size_type pos, string, size_type, size_type)</code> is 3725required to throw <code>out_of_range</code> if <code>pos > 3726size()</code>. 3727</p> 3728 3729<p> 3730<code>insert(size_type pos, string str)</code> is specified to return 3731<code>insert(pos, str, 0, npos)</code> by a <i>Returns</i> clause and 3732so its effects when <code>pos > size()</code> are strictly speaking 3733unspecified. 3734</p><p> 3735 3736</p> 3737I believe a careful review of the current <i>Effects</i> and 3738<i>Returns</i> clauses is needed in order to identify all such 3739problematic cases. In addition, a review of the Working Paper should 3740be done to make sure that the newly introduced normative <i>Remark</i> 3741clauses do not impose any undesirable normative requirements in place 3742of the original informative <i>Notes</i>. 3743 3744 3745<p><i>[ 3746Batavia: Alan and Pete to work. 3747]</i></p> 3748 3749 3750<p><i>[ 3751Bellevue: Marked as NAD Editorial. 3752]</i></p> 3753 3754 3755<p><i>[ 3756Post-Sophia Antipolis: 3757Martin indicates there is still work to be done on this issue. 3758Reopened. 3759]</i></p> 3760 3761 3762<p><i>[ 3763Batavia (2009-05): 3764]</i></p> 3765 3766<blockquote> 3767Tom proposes we say that, unless specified otherwise, 3768it is always the caller's responsibility to verify that supplied arguments 3769meet the called function's requirements. 3770If further semantics are specified 3771(e.g., that the function throws under certain conditions), 3772then it is up to the implementer to check those conditions. 3773Alan feels strongly that our current use of Requires in this context 3774is confusing, especially now that <tt>requires</tt> is a new keyword. 3775</blockquote> 3776 3777<p><i>[ 37782009-07 Frankfurt 3779]</i></p> 3780 3781 3782<blockquote> 3783Move to Tentatively NAD. 3784</blockquote> 3785 3786<p><i>[ 37872009 Santa Cruz: 3788]</i></p> 3789 3790 3791<blockquote> 3792Move to Open. Martin will work on proposed wording. 3793</blockquote> 3794 3795 3796 3797<p><b>Proposed resolution:</b></p> 3798<p> 3799</p> 3800 3801 3802 3803 3804 3805<hr> 3806<h3><a name="631"></a>631. conflicting requirements for <tt>BinaryPredicate</tt></h3> 3807<p><b>Section:</b> 25 [algorithms] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Review">Review</a> 3808 <b>Submitter:</b> James Kanze <b>Opened:</b> 2007-01-31 <b>Last modified:</b> 2009-10-24</p> 3809<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#algorithms">active issues</a> in [algorithms].</p> 3810<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#algorithms">issues</a> in [algorithms].</p> 3811<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Review">Review</a> status.</p> 3812<p><b>Discussion:</b></p> 3813<p> 3814The general requirements for <tt><tt>BinaryPredicate</tt></tt> (in 25 [algorithms]/8) contradict the implied specific requirements for 3815some functions. In particular, it says that: 3816</p> 3817 3818<blockquote><p> 3819[...] if an algorithm takes <tt>BinaryPredicate <i>binary_pred</i></tt> 3820as its argument and <tt><i>first1</i></tt> and <i>first2</i> as its 3821iterator arguments, it should work correctly in the construct <tt>if 3822(binary_pred (*<i>first1</i> , *<i>first2</i> )){...}</tt>. 3823<tt>BinaryPredicate</tt> always takes the first iterator type as its 3824first argument, that is, in those cases when <tt>T <i>value</i></tt> is 3825part of the signature, it should work correctly in the context of <tt>if 3826(binary_pred (*<i>first1</i> , <i>value</i>)){...}</tt>. 3827</p></blockquote> 3828 3829<p> 3830In the description of <tt>upper_bound</tt> (25.4.3.2 [upper.bound]/2), however, the use is described as 3831"<tt>!comp(<i>value</i>, <i>e</i>)</tt>", where <tt><i>e</i></tt> is an 3832element of the sequence (a result of dereferencing 3833<tt>*<i>first</i></tt>). 3834</p> 3835 3836<p> 3837In the description of <tt>lexicographical_compare</tt>, we have both 3838"<tt>*<i>first1</i> < *<i>first2</i></tt>" and "<tt>*<i>first2</i> 3839< *<i>first1</i></tt>" (which presumably implies "<tt>comp( 3840*<i>first1</i>, *<i>first2</i> )</tt>" and "<tt>comp( *<i>first2</i>, 3841*<i>first1</i> )</tt>". 3842</p> 3843 3844<p><i>[ 3845Toronto: Moved to Open. ConceptGCC seems to get <tt>lower_bound</tt> 3846and <tt>upper_bound</tt> to work withoutt these changes. 3847]</i></p> 3848 3849 3850<p><i>[ 38512009-07-28 Reopened by Alisdair. No longer solved by concepts. 3852]</i></p> 3853 3854 3855<p><i>[ 38562009-10 Santa Cruz: 3857]</i></p> 3858 3859 3860<blockquote> 3861Move to Review. The small problem with the "iterator type" 3862will be fixed. The cited functions (<tt>lower_bound</tt>, <tt>uppwer_bound</tt>, 3863<tt>equal_range</tt>) don't actually use <tt>BinaryPredicate</tt> , and where it is used, 3864it is consistent with [algorithm]/8, so the main complaint of the issue 3865is moot. 3866</blockquote> 3867 3868 3869 3870<p><b>Proposed resolution:</b></p> 3871<p> 3872Logically, the <tt>BinaryPredicate</tt> is used as an ordering 3873relationship, with the semantics of "less than". Depending on the 3874function, it may be used to determine equality, or any of the inequality 3875relationships; doing this requires being able to use it with either 3876parameter first. I would thus suggest that the requirement be: 3877</p> 3878 3879<blockquote><p> 3880[...] <tt>BinaryPredicate</tt> always takes the first iterator 3881<tt>value_type</tt> as one of its arguments, it is unspecified which. If 3882an algorithm takes <tt>BinaryPredicate <i>binary_pred</i></tt> as its 3883argument and <tt><i><i>first1</i></i></tt> and <i>first2</i> as its 3884iterator arguments, it should work correctly both in the construct 3885<tt>if (binary_pred (*<i>first1</i> , *<i>first2</i> )){...}</tt> and 3886<tt>if (binary_pred (*<i>first2</i>, *<i>first1</i>)){...}</tt>. In 3887those cases when <tt>T <i>value</i></tt> is part of the signature, it 3888should work correctly in the context of <tt>if (binary_pred 3889(*<i>first1</i> , <i>value</i>)){...}</tt> and of <tt>if (binary_pred 3890(<i>value</i>, *<i>first1</i>)){...}</tt>. [<i>Note:</i> if the two 3891types are not identical, and neither is convertable to the other, this 3892may require that the <tt>BinaryPredicate</tt> be a functional object 3893with two overloaded <tt>operator()()</tt> functions. <i>--end note</i>] 3894</p></blockquote> 3895 3896<p> 3897Alternatively, one could specify an order for each function. IMHO, this 3898would be more work for the committee, more work for the implementors, 3899and of no real advantage for the user: some functions, such as 3900<tt>lexicographical_compare</tt> or <tt>equal_range</tt>, will still require both 3901functions, and it seems like a much easier rule to teach that both 3902functions are always required, rather than to have a complicated list of 3903when you only need one, and which one. 3904</p> 3905 3906 3907<p><b>Rationale:</b></p> 3908<p><i>[ 3909post San Francisco: 3910]</i></p> 3911 3912 3913<blockquote> 3914Solved by 3915<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2759.pdf">N2759</a>. 3916</blockquote> 3917 3918 3919 3920 3921 3922 3923<hr> 3924<h3><a name="671"></a>671. precision of hexfloat</h3> 3925<p><b>Section:</b> 22.4.2.2.2 [facet.num.put.virtuals] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 3926 <b>Submitter:</b> John Salmon <b>Opened:</b> 2007-04-20 <b>Last modified:</b> 2009-10-21</p> 3927<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#facet.num.put.virtuals">active issues</a> in [facet.num.put.virtuals].</p> 3928<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#facet.num.put.virtuals">issues</a> in [facet.num.put.virtuals].</p> 3929<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 3930<p><b>Discussion:</b></p> 3931<p> 3932I am trying to understand how TR1 supports hex float (%a) output. 3933</p> 3934<p> 3935As far as I can tell, it does so via the following: 3936</p> 3937<p> 39388.15 Additions to header <locale> [tr.c99.locale] 3939</p> 3940<p> 3941In subclause 22.4.2.2.2 [facet.num.put.virtuals], Table 58 Floating-point conversions, after 3942the line: 3943floatfield == ios_base::scientific %E 3944</p> 3945<p> 3946add the two lines: 3947</p> 3948<blockquote><pre>floatfield == ios_base::fixed | ios_base::scientific && !uppercase %a 3949floatfield == ios_base::fixed | ios_base::scientific %A 2 3950</pre></blockquote> 3951<p> 3952[Note: The additional requirements on print and scan functions, later 3953in this clause, ensure that the print functions generate hexadecimal 3954floating-point fields with a %a or %A conversion specifier, and that 3955the scan functions match hexadecimal floating-point fields with a %g 3956conversion specifier. end note] 3957</p> 3958<p> 3959Following the thread, in 22.4.2.2.2 [facet.num.put.virtuals], we find: 3960</p> 3961<p> 3962For conversion from a floating-point type, if (flags & fixed) != 0 or 3963if str.precision() > 0, then str.precision() is specified in the 3964conversion specification. 3965</p> 3966<p> 3967This would seem to imply that when floatfield == fixed|scientific, the 3968precision of the conversion specifier is to be taken from 3969str.precision(). Is this really what's intended? I sincerely hope 3970that I'm either missing something or this is an oversight. Please 3971tell me that the committee did not intend to mandate that hex floats 3972(and doubles) should by default be printed as if by %.6a. 3973</p> 3974 3975<p><i>[ 3976Howard: I think the fundamental issue we overlooked was that with %f, 3977%e, %g, the default precision was always 6. With %a the default 3978precision is not 6, it is infinity. So for the first time, we need to 3979distinguish between the default value of precision, and the precision 3980value 6. 3981]</i></p> 3982 3983 3984<p><i>[ 39852009-07 Frankfurt 3986]</i></p> 3987 3988 3989<blockquote> 3990<p> 3991Leave this open for Robert and Daniel to work on. 3992</p> 3993<p> 3994Straw poll: Disposition? 3995</p> 3996<ul> 3997<li>Default is %.6a (i.e. NAD): 2</li> 3998<li>Always %a (no precision): 6</li> 3999<li>precision(-1) == %a: 3</li> 4000</ul> 4001<p> 4002Daniel and Robert have direction to write up wording for the "always %a" solution. 4003</p> 4004 4005<p><i>[ 40062009-07-15 Robert provided wording. 4007]</i></p> 4008 4009</blockquote> 4010 4011<p><i>[ 40122009-10 Santa Cruz: 4013]</i></p> 4014 4015 4016<blockquote> 4017Move to Ready. 4018</blockquote> 4019 4020 4021 4022<p><b>Proposed resolution:</b></p> 4023<p> 4024Change 22.4.2.2.2 [facet.num.put.virtuals], Stage 1, under p5 (near the end 4025of Stage 1): 4026</p> 4027 4028<blockquote> 4029For conversion from a floating-point type, <tt>str.precision()</tt> is specified 4030<ins>as precision</ins> in the conversion specification 4031<ins>if <tt>floatfield != (ios_base::fixed | ios_base::scientific)</tt>, else no 4032precision is specified</ins>. 4033</blockquote> 4034 4035 4036 4037<p><i>[ 4038Kona (2007): Robert volunteers to propose wording. 4039]</i></p> 4040 4041 4042 4043 4044 4045<hr> 4046<h3><a name="676"></a>676. Moving the unordered containers</h3> 4047<p><b>Section:</b> 23.5 [unord] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Review">Review</a> 4048 <b>Submitter:</b> Howard Hinnant <b>Opened:</b> 2007-05-05 <b>Last modified:</b> 2009-10-29</p> 4049<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#unord">issues</a> in [unord].</p> 4050<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Review">Review</a> status.</p> 4051<p><b>Discussion:</b></p> 4052<p> 4053Move semantics are missing from the <tt>unordered</tt> containers. The proposed 4054resolution below adds move-support consistent with 4055<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2005/n1858.html">N1858</a> 4056and the current working draft. 4057</p> 4058 4059<p> 4060The current proposed resolution simply lists the requirements for each function. 4061These might better be hoisted into the requirements table for unordered associative containers. 4062Futhermore a mild reorganization of the container requirements could well be in order. 4063This defect report is purposefully ignoring these larger issues and just focusing 4064on getting the unordered containers "moved". 4065</p> 4066 4067<p><i>[ 40682009-07-28 Reopened by Alisdair. No longer solved by concepts. 4069]</i></p> 4070 4071 4072<p><i>[ 40732009-10-17 Removed rvalue-swaps from wording. 4074]</i></p> 4075 4076 4077<p><i>[ 40782009-10 Santa Cruz: 4079]</i></p> 4080 4081 4082<blockquote> 4083Move to Review. Alisdair will review proposed wording. 4084</blockquote> 4085 4086<p><i>[ 40872009-10-29 Daniel updates wording. 4088]</i></p> 4089 4090 4091 4092 4093<p><b>Proposed resolution:</b></p> 4094 4095<p><b><tt>unordered_map</tt></b></p> 4096 4097<p> 4098Change 23.5.1 [unord.map]: 4099</p> 4100 4101<blockquote><pre>class unordered_map 4102{ 4103 ... 4104 unordered_map(const unordered_map&); 4105 <ins>unordered_map(unordered_map&&);</ins> 4106 ~unordered_map(); 4107 unordered_map& operator=(const unordered_map&); 4108 <ins>unordered_map& operator=(unordered_map&&);</ins> 4109 ... 4110 // modifiers 4111 <del>std::</del>pair<iterator, bool> insert(const value_type& obj); 4112 <ins>template <class P> pair<iterator, bool> insert(P&& obj);</ins> 4113 iterator insert(const_iterator hint, const value_type& obj); 4114 <ins>template <class P> iterator insert(const_iterator hint, P&& obj);</ins> 4115 ... 4116 mapped_type& operator[](const key_type& k); 4117 <ins>mapped_type& operator[](key_type&& k);</ins> 4118 ... 4119}; 4120 4121</pre></blockquote> 4122 4123<p> 4124Add to 23.5.1.1 [unord.map.cnstr]: 4125</p> 4126 4127<blockquote> 4128<pre>template <class InputIterator> 4129 unordered_map(InputIterator f, InputIterator l, 4130 size_type n = <i>implementation-defined</i>, 4131 const hasher& hf = hasher(), 4132 const key_equal& eql = key_equal(), 4133 const allocator_type& a = allocator_type()); 4134</pre> 4135 4136<blockquote><p> 4137<ins> 4138<i>Requires:</i> If the iterator's dereference operator returns an 4139lvalue or a const rvalue <tt>pair<key_type, mapped_type></tt>, 4140then both <tt>key_type</tt> and <tt>mapped_type</tt> shall be 4141<tt>CopyConstructible</tt>. 4142</ins> 4143</p></blockquote> 4144</blockquote> 4145 4146<p> 4147Add to 23.5.1.2 [unord.map.elem]: 4148</p> 4149 4150<blockquote> 4151 4152<pre>mapped_type& operator[](const key_type& k);</pre> 4153 4154<blockquote> 4155<p>...</p> 4156<p><ins> 4157<i>Requires:</i> <tt>key_type</tt> shall be <tt>CopyConstructible</tt> 4158and <tt>mapped_type</tt> shall be <tt>DefaultConstructible</tt>. 4159</ins></p> 4160</blockquote> 4161 4162<pre><ins>mapped_type& operator[](key_type&& k);</ins></pre> 4163 4164<blockquote> 4165<p><ins> 4166<i>Effects:</i> If the <tt>unordered_map</tt> does not already contain an 4167element whose key is equivalent to <tt>k</tt> , inserts the value 4168<tt>std::pair<const key_type, mapped_type>(std::move(k), mapped_type())</tt>. 4169</ins></p> 4170 4171<p><ins> 4172<i>Requires:</i> <tt>mapped_type</tt> shall be <tt>DefaultConstructible</tt>. 4173</ins></p> 4174 4175<p><ins> 4176<i>Returns:</i> A reference to <tt>x.second</tt>, where <tt>x</tt> is the 4177(unique) element whose key is equivalent to <tt>k</tt>. 4178</ins></p> 4179 4180</blockquote> 4181 4182</blockquote> 4183 4184<p> 4185Add new section [unord.map.modifiers]: 4186</p> 4187 4188<blockquote> 4189<pre><ins>pair<iterator, bool> insert(const value_type& x);</ins> 4190<ins>template <class P> pair<iterator, bool> insert(P&& x);</ins> 4191<ins>iterator insert(const_iterator hint, const value_type& x);</ins> 4192<ins>template <class P> iterator insert(const_iterator hint, P&& x);</ins> 4193<ins>template <class InputIterator> 4194 void insert(InputIterator first, InputIterator last);</ins> 4195</pre> 4196 4197<blockquote> 4198<p><ins> 4199<i>Requires:</i> Those signatures taking a <tt>const value_type&</tt> parameter 4200requires both the <tt>key_type</tt> and the <tt>mapped_type</tt> to be 4201<tt>CopyConstructible</tt>. 4202 If <tt>P</tt> is instantiated as a reference 4203type, then the argument <tt>x</tt> is copied from. Otherwise <tt>x</tt> 4204is considered to be an rvalue as it is converted to <tt>value_type</tt> 4205and inserted into the <tt>unordered_map</tt>. Specifically, in such 4206cases <tt>CopyConstructible</tt> is not required for <tt>key_type</tt> or 4207<tt>mapped_type</tt> unless the conversion from <tt>P</tt> specifically 4208requires it (e.g. if <tt>P</tt> is a <tt>tuple<const key_type, 4209mapped_type></tt>, then <tt>key_type</tt> must be 4210<tt>CopyConstructible</tt>). 4211</ins></p> 4212 4213<p><ins> 4214The signature taking <tt>InputIterator</tt> 4215parameters requires <tt>CopyConstructible</tt> of both 4216<tt>key_type</tt> and <tt>mapped_type</tt> if the dereferenced 4217<tt>InputIterator</tt> returns an lvalue or <tt>const</tt> rvalue 4218<tt>value_type</tt>. 4219</ins></p> 4220 4221</blockquote> 4222 4223</blockquote> 4224 4225<p><b><tt>unordered_multimap</tt></b></p> 4226 4227<p> 4228Change 23.5.2 [unord.multimap]: 4229</p> 4230 4231<blockquote><pre>class unordered_multimap 4232{ 4233 ... 4234 unordered_multimap(const unordered_multimap&); 4235 <ins>unordered_multimap(unordered_multimap&&);</ins> 4236 ~unordered_multimap(); 4237 unordered_multimap& operator=(const unordered_multimap&); 4238 <ins>unordered_multimap& operator=(unordered_multimap&&);</ins> 4239 ... 4240 // modifiers 4241 iterator insert(const value_type& obj); 4242 <ins>template <class P> iterator insert(P&& obj);</ins> 4243 iterator insert(const_iterator hint, const value_type& obj); 4244 <ins>template <class P> iterator insert(const_iterator hint, P&& obj);</ins> 4245 ... 4246}; 4247 4248</pre></blockquote> 4249 4250<p> 4251Add to 23.5.2.1 [unord.multimap.cnstr]: 4252</p> 4253 4254<blockquote> 4255<pre>template <class InputIterator> 4256 unordered_multimap(InputIterator f, InputIterator l, 4257 size_type n = <i>implementation-defined</i>, 4258 const hasher& hf = hasher(), 4259 const key_equal& eql = key_equal(), 4260 const allocator_type& a = allocator_type()); 4261</pre> 4262 4263<blockquote><p> 4264<ins> 4265<i>Requires:</i> If the iterator's dereference operator returns an 4266lvalue or a const rvalue <tt>pair<key_type, mapped_type></tt>, 4267then both <tt>key_type</tt> and <tt>mapped_type</tt> shall be 4268<tt>CopyConstructible</tt>. 4269</ins> 4270</p></blockquote> 4271</blockquote> 4272 4273<p> 4274Add new section [unord.multimap.modifiers]: 4275</p> 4276 4277<blockquote> 4278<pre><ins>iterator insert(const value_type& x);</ins> 4279<ins>template <class P> iterator insert(P&& x);</ins> 4280<ins>iterator insert(const_iterator hint, const value_type& x);</ins> 4281<ins>template <class P> iterator insert(const_iterator hint, P&& x);</ins> 4282<ins>template <class InputIterator> 4283 void insert(InputIterator first, InputIterator last);</ins> 4284</pre> 4285 4286<blockquote> 4287<p><ins> 4288<i>Requires:</i> Those signatures taking a <tt>const value_type&</tt> parameter 4289requires both the <tt>key_type</tt> and the <tt>mapped_type</tt> to be 4290<tt>CopyConstructible</tt>. 4291If <tt>P</tt> is instantiated as a reference 4292type, then the argument <tt>x</tt> is copied from. Otherwise <tt>x</tt> 4293is considered to be an rvalue as it is converted to <tt>value_type</tt> 4294and inserted into the <tt>unordered_multimap</tt>. Specifically, in such 4295cases <tt>CopyConstructible</tt> is not required for <tt>key_type</tt> or 4296<tt>mapped_type</tt> unless the conversion from <tt>P</tt> specifically 4297requires it (e.g. if <tt>P</tt> is a <tt>tuple<const key_type, 4298mapped_type></tt>, then <tt>key_type</tt> must be 4299<tt>CopyConstructible</tt>). 4300</ins></p> 4301 4302<p><ins> 4303The signature taking <tt>InputIterator</tt> 4304parameters requires <tt>CopyConstructible</tt> of both 4305<tt>key_type</tt> and <tt>mapped_type</tt> if the dereferenced 4306<tt>InputIterator</tt> returns an lvalue or <tt>const</tt> rvalue 4307<tt>value_type</tt>. 4308</ins></p> 4309</blockquote> 4310 4311</blockquote> 4312 4313<p><b><tt>unordered_set</tt></b></p> 4314 4315<p> 4316Change 23.5.3 [unord.set]: 4317</p> 4318 4319<blockquote><pre>class unordered_set 4320{ 4321 ... 4322 unordered_set(const unordered_set&); 4323 <ins>unordered_set(unordered_set&&);</ins> 4324 ~unordered_set(); 4325 unordered_set& operator=(const unordered_set&); 4326 <ins>unordered_set& operator=(unordered_set&&);</ins> 4327 ... 4328 // modifiers 4329 <del>std::</del>pair<iterator, bool> insert(const value_type& obj); 4330 <ins>pair<iterator, bool> insert(value_type&& obj);</ins> 4331 iterator insert(const_iterator hint, const value_type& obj); 4332 <ins>iterator insert(const_iterator hint, value_type&& obj);</ins> 4333 ... 4334}; 4335</pre></blockquote> 4336 4337<p> 4338Add to 23.5.3.1 [unord.set.cnstr]: 4339</p> 4340 4341<blockquote> 4342<pre>template <class InputIterator> 4343 unordered_set(InputIterator f, InputIterator l, 4344 size_type n = <i>implementation-defined</i>, 4345 const hasher& hf = hasher(), 4346 const key_equal& eql = key_equal(), 4347 const allocator_type& a = allocator_type()); 4348</pre> 4349 4350<blockquote><p> 4351<ins> 4352<i>Requires:</i> If the iterator's dereference operator returns an 4353lvalue or a const rvalue <tt>value_type</tt>, then the 4354<tt>value_type</tt> shall be <tt>CopyConstructible</tt>. 4355</ins> 4356</p></blockquote> 4357</blockquote> 4358 4359<p> 4360Add new section [unord.set.modifiers]: 4361</p> 4362 4363<blockquote> 4364<pre><ins>pair<iterator, bool> insert(const value_type& x);</ins> 4365<ins>pair<iterator, bool> insert(value_type&& x);</ins> 4366<ins>iterator insert(const_iterator hint, const value_type& x);</ins> 4367<ins>iterator insert(const_iterator hint, value_type&& x);</ins> 4368<ins>template <class InputIterator> 4369 void insert(InputIterator first, InputIterator last);</ins> 4370</pre> 4371 4372<blockquote> 4373 4374<p><ins> 4375<i>Requires:</i> Those signatures taking a <tt>const 4376value_type&</tt> parameter requires the <tt>value_type</tt> to 4377be <tt>CopyConstructible</tt>. 4378</ins></p> 4379 4380<p><ins> 4381The signature taking <tt>InputIterator</tt> parameters requires 4382<tt>CopyConstructible</tt> of <tt>value_type</tt> if the dereferenced 4383<tt>InputIterator</tt> returns an lvalue or <tt>const</tt> rvalue 4384<tt>value_type</tt>. 4385</ins></p> 4386 4387</blockquote> 4388 4389</blockquote> 4390 4391<p><b><tt>unordered_multiset</tt></b></p> 4392 4393<p> 4394Change 23.5.4 [unord.multiset]: 4395</p> 4396 4397<blockquote><pre>class unordered_multiset 4398{ 4399 ... 4400 unordered_multiset(const unordered_multiset&); 4401 <ins>unordered_multiset(unordered_multiset&&);</ins> 4402 ~unordered_multiset(); 4403 unordered_multiset& operator=(const unordered_multiset&); 4404 <ins>unordered_multiset& operator=(unordered_multiset&&);</ins> 4405 ... 4406 // modifiers 4407 iterator insert(const value_type& obj); 4408 <ins>iterator insert(value_type&& obj);</ins> 4409 iterator insert(const_iterator hint, const value_type& obj); 4410 <ins>iterator insert(const_iterator hint, value_type&& obj);</ins> 4411 ... 4412}; 4413 4414</pre></blockquote> 4415 4416<p> 4417Add to 23.5.4.1 [unord.multiset.cnstr]: 4418</p> 4419 4420<blockquote> 4421<pre>template <class InputIterator> 4422 unordered_multiset(InputIterator f, InputIterator l, 4423 size_type n = <i>implementation-defined</i>, 4424 const hasher& hf = hasher(), 4425 const key_equal& eql = key_equal(), 4426 const allocator_type& a = allocator_type()); 4427</pre> 4428 4429<blockquote><p> 4430<ins> 4431<i>Requires:</i> If the iterator's dereference operator returns an 4432lvalue or a const rvalue <tt>value_type</tt>, then the 4433<tt>value_type</tt> shall be <tt>CopyConstructible</tt>. 4434</ins> 4435</p></blockquote> 4436</blockquote> 4437 4438<p> 4439Add new section [unord.multiset.modifiers]: 4440</p> 4441 4442<blockquote> 4443<pre><ins>iterator insert(const value_type& x);</ins> 4444<ins>iterator insert(value_type&& x);</ins> 4445<ins>iterator insert(const_iterator hint, const value_type& x);</ins> 4446<ins>iterator insert(const_iterator hint, value_type&& x);</ins> 4447<ins>template <class InputIterator> 4448 void insert(InputIterator first, InputIterator last);</ins> 4449</pre> 4450 4451<blockquote> 4452 4453<p><ins> 4454<i>Requires:</i> Those signatures taking a <tt>const 4455value_type&</tt> parameter requires the <tt>value_type</tt> to 4456be <tt>CopyConstructible</tt>. 4457</ins></p> 4458 4459<p><ins> 4460The signature taking <tt>InputIterator</tt> parameters requires 4461<tt>CopyConstructible</tt> of <tt>value_type</tt> if the dereferenced 4462<tt>InputIterator</tt> returns an lvalue or <tt>const</tt> rvalue 4463<tt>value_type</tt>. 4464</ins></p> 4465 4466</blockquote> 4467 4468</blockquote> 4469 4470 4471 4472<p><i>[ 4473Voted to WP in Bellevue. 4474]</i></p> 4475 4476 4477<p><i>[ 4478post Bellevue, Pete notes: 4479]</i></p> 4480 4481 4482<blockquote> 4483<p> 4484Please remind people who are reviewing issues to check that the text 4485modifications match the current draft. Issue 676, for example, adds two 4486overloads for unordered_map::insert taking a hint. One takes a 4487const_iterator and returns a const_iterator, and the other takes an 4488iterator and returns an iterator. This was correct at the time the issue 4489was written, but was changed in Toronto so there is only one hint 4490overload, taking a const_iterator and returning an iterator. 4491</p> 4492<p> 4493This issue is not ready. In addition to the relatively minor signature 4494problem I mentioned earlier, it puts requirements in the wrong places. 4495Instead of duplicating requirements throughout the template 4496specifications, it should put them in the front matter that talks about 4497requirements for unordered containers in general. This presentation 4498problem is editorial, but I'm not willing to do the extensive rewrite 4499that it requires. Please put it back into Open status. 4500</p> 4501</blockquote> 4502 4503<p><b>Rationale:</b></p> 4504<p><i>[ 4505San Francisco: 4506]</i></p> 4507 4508 4509<blockquote> 4510Solved by 4511<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2776.pdf">N2776</a>. 4512</blockquote> 4513 4514 4515 4516 4517 4518 4519<hr> 4520<h3><a name="704"></a>704. MoveAssignable requirement for container value type overly strict</h3> 4521<p><b>Section:</b> 23.2 [container.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 4522 <b>Submitter:</b> Howard Hinnant <b>Opened:</b> 2007-05-20 <b>Last modified:</b> 2009-10-20</p> 4523<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#container.requirements">active issues</a> in [container.requirements].</p> 4524<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#container.requirements">issues</a> in [container.requirements].</p> 4525<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 4526<p><b>Discussion:</b></p> 4527<p> 4528The move-related changes inadvertently overwrote the intent of <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#276">276</a>. 4529Issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#276">276</a> removed the requirement of <tt>CopyAssignable</tt> from 4530most of the member functions of node-based containers. But the move-related changes 4531unnecessarily introduced the <tt>MoveAssignable</tt> requirement for those members which used to 4532require <tt>CopyAssignable</tt>. 4533</p> 4534 4535<p> 4536We also discussed (c++std-lib-18722) the possibility of dropping <tt>MoveAssignable</tt> 4537from some of the sequence requirements. Additionally the <i>in-place</i> construction 4538work may further reduce requirements. For purposes of an easy reference, here are the 4539minimum sequence requirements as I currently understand them. Those items in requirements 4540table in the working draft which do not appear below have been purposefully omitted for 4541brevity as they do not have any requirements of this nature. Some items which do not 4542have any requirements of this nature are included below just to confirm that they were 4543not omitted by mistake. 4544</p> 4545 4546<table border="1"> 4547<caption>Container Requirements</caption> 4548<tbody><tr><td><tt>X u(a)</tt></td><td><tt>value_type</tt> must be <tt>CopyConstructible</tt></td></tr> 4549<tr><td><tt>X u(rv)</tt></td><td><tt>array</tt> and containers with a <tt>propagate_never</tt> allocator require <tt>value_type</tt> to be <tt>MoveConstructible</tt></td></tr> 4550<tr><td><tt>a = u</tt></td><td>Sequences require <tt>value_type</tt> to be <tt>CopyConstructible</tt> and <tt>CopyAssignable</tt>. 4551 Associative containers require <tt>value_type</tt> to be <tt>CopyConstructible</tt>.</td></tr> 4552<tr><td><tt>a = rv</tt></td><td><tt>array</tt> requires <tt>value_type</tt> to be <tt>MoveAssignable</tt>. 4553 Sequences and Associative containers with <tt>propagate_never</tt> and <tt>propagate_on_copy_construction</tt> allocators require <tt>value_type</tt> to be <tt>MoveConstructible</tt>.</td></tr> 4554<tr><td><tt>swap(a,u)</tt></td><td><tt>array</tt> and containers with <tt>propagate_never</tt> and 4555 <tt>propagate_on_copy_construction</tt> allocators require <tt>value_type</tt> to be <tt>Swappable</tt>.</td></tr> 4556</tbody></table> 4557 4558<p> 4559</p> 4560 4561<table border="1"> 4562<caption>Sequence Requirements</caption> 4563<tbody><tr><td><tt>X(n)</tt></td><td><tt>value_type</tt> must be <tt>DefaultConstructible</tt></td></tr> 4564<tr><td><tt>X(n, t)</tt></td><td><tt>value_type</tt> must be <tt>CopyConstructible</tt></td></tr> 4565<tr><td><tt>X(i, j)</tt></td><td>If the iterators return an lvalue the <tt>value_type</tt> must be <tt>CopyConstructible</tt>. 4566 If the iterators return an rvalue the <tt>value_type</tt> must be <tt>MoveConstructible</tt>.</td></tr> 4567<tr><td><tt>a.insert(p, t)</tt></td><td>The <tt>value_type</tt> must be <tt>CopyConstructible</tt>. 4568 The sequences <tt>vector</tt> and <tt>deque</tt> also require the <tt>value_type</tt> to be <tt>CopyAssignable</tt>.</td></tr> 4569<tr><td><tt>a.insert(p, rv)</tt></td><td>The <tt>value_type</tt> must be <tt>MoveConstructible</tt>. 4570 The sequences <tt>vector</tt> and <tt>deque</tt> also require the <tt>value_type</tt> to be <tt>MoveAssignable</tt>.</td></tr> 4571<tr><td><tt>a.insert(p, n, t)</tt></td><td>The <tt>value_type</tt> must be <tt>CopyConstructible</tt>. 4572 The sequences <tt>vector</tt> and <tt>deque</tt> also require the <tt>value_type</tt> to be <tt>CopyAssignable</tt>.</td></tr> 4573<tr><td><tt>a.insert(p, i, j)</tt></td><td>If the iterators return an lvalue the <tt>value_type</tt> must be <tt>CopyConstructible</tt>. 4574 The sequences <tt>vector</tt> and <tt>deque</tt> also require the <tt>value_type</tt> to be <tt>CopyAssignable</tt> when the iterators return an lvalue. 4575 If the iterators return an rvalue the <tt>value_type</tt> must be <tt>MoveConstructible</tt>. 4576 The sequences <tt>vector</tt> and <tt>deque</tt> also require the <tt>value_type</tt> to be <tt>MoveAssignable</tt> when the iterators return an rvalue.</td></tr> 4577<tr><td><tt>a.erase(p)</tt></td><td>The sequences <tt>vector</tt> and <tt>deque</tt> require the <tt>value_type</tt> to be <tt>MoveAssignable</tt>.</td></tr> 4578<tr><td><tt>a.erase(q1, q2)</tt></td><td>The sequences <tt>vector</tt> and <tt>deque</tt> require the <tt>value_type</tt> to be <tt>MoveAssignable</tt>.</td></tr> 4579<tr><td><tt>a.clear()</tt></td><td></td></tr> 4580<tr><td><tt>a.assign(i, j)</tt></td><td>If the iterators return an lvalue the <tt>value_type</tt> must be <tt>CopyConstructible</tt> and <tt>CopyAssignable</tt>. 4581 If the iterators return an rvalue the <tt>value_type</tt> must be <tt>MoveConstructible</tt> and <tt>MoveAssignable</tt>.</td></tr> 4582<tr><td><tt>a.assign(n, t)</tt></td><td>The <tt>value_type</tt> must be <tt>CopyConstructible</tt> and <tt>CopyAssignable</tt>.</td></tr> 4583<tr><td><tt>a.resize(n)</tt></td><td>The <tt>value_type</tt> must be <tt>DefaultConstructible</tt>. 4584 The sequence <tt>vector</tt> also requires the <tt>value_type</tt> to be <tt>MoveConstructible</tt>.</td></tr> 4585<tr><td><tt>a.resize(n, t)</tt></td><td>The <tt>value_type</tt> must be <tt>CopyConstructible</tt>.</td></tr> 4586</tbody></table> 4587 4588<p> 4589</p> 4590 4591<table border="1"> 4592<caption>Optional Sequence Requirements</caption> 4593<tbody><tr><td><tt>a.front()</tt></td><td></td></tr> 4594<tr><td><tt>a.back()</tt></td><td></td></tr> 4595<tr><td><tt>a.push_front(t)</tt></td><td>The <tt>value_type</tt> must be <tt>CopyConstructible</tt>.</td></tr> 4596<tr><td><tt>a.push_front(rv)</tt></td><td>The <tt>value_type</tt> must be <tt>MoveConstructible</tt>.</td></tr> 4597<tr><td><tt>a.push_back(t)</tt></td><td>The <tt>value_type</tt> must be <tt>CopyConstructible</tt>.</td></tr> 4598<tr><td><tt>a.push_back(rv)</tt></td><td>The <tt>value_type</tt> must be <tt>MoveConstructible</tt>.</td></tr> 4599<tr><td><tt>a.pop_front()</tt></td><td></td></tr> 4600<tr><td><tt>a.pop_back()</tt></td><td></td></tr> 4601<tr><td><tt>a[n]</tt></td><td></td></tr> 4602<tr><td><tt>a.at[n]</tt></td><td></td></tr> 4603</tbody></table> 4604 4605<p> 4606</p> 4607 4608<table border="1"> 4609<caption>Associative Container Requirements</caption> 4610<tbody><tr><td><tt>X(i, j)</tt></td><td>If the iterators return an lvalue the <tt>value_type</tt> must be <tt>CopyConstructible</tt>. 4611 If the iterators return an rvalue the <tt>value_type</tt> must be <tt>MoveConstructible</tt>.</td></tr> 4612<tr><td><tt>a_uniq.insert(t)</tt></td><td>The <tt>value_type</tt> must be <tt>CopyConstructible</tt>.</td></tr> 4613<tr><td><tt>a_uniq.insert(rv)</tt></td><td>The <tt>key_type</tt> and the <tt>mapped_type</tt> (if it exists) must be <tt>MoveConstructible</tt>.</td></tr> 4614<tr><td><tt>a_eq.insert(t)</tt></td><td>The <tt>value_type</tt> must be <tt>CopyConstructible</tt>.</td></tr> 4615<tr><td><tt>a_eq.insert(rv)</tt></td><td>The <tt>key_type</tt> and the <tt>mapped_type</tt> (if it exists) must be <tt>MoveConstructible</tt>.</td></tr> 4616<tr><td><tt>a.insert(p, t)</tt></td><td>The <tt>value_type</tt> must be <tt>CopyConstructible</tt>.</td></tr> 4617<tr><td><tt>a.insert(p, rv)</tt></td><td>The <tt>key_type</tt> and the <tt>mapped_type</tt> (if it exists) must be <tt>MoveConstructible</tt>.</td></tr> 4618<tr><td><tt>a.insert(i, j)</tt></td><td>If the iterators return an lvalue the <tt>value_type</tt> must be <tt>CopyConstructible</tt>. 4619 If the iterators return an rvalue the <tt>key_type</tt> and the <tt>mapped_type</tt> (if it exists) must be <tt>MoveConstructible</tt>..</td></tr> 4620</tbody></table> 4621 4622<p> 4623</p> 4624 4625<table border="1"> 4626<caption>Unordered Associative Container Requirements</caption> 4627<tbody><tr><td><tt>X(i, j, n, hf, eq)</tt></td><td>If the iterators return an lvalue the <tt>value_type</tt> must be <tt>CopyConstructible</tt>. 4628 If the iterators return an rvalue the <tt>value_type</tt> must be <tt>MoveConstructible</tt>.</td></tr> 4629<tr><td><tt>a_uniq.insert(t)</tt></td><td>The <tt>value_type</tt> must be <tt>CopyConstructible</tt>.</td></tr> 4630<tr><td><tt>a_uniq.insert(rv)</tt></td><td>The <tt>key_type</tt> and the <tt>mapped_type</tt> (if it exists) must be <tt>MoveConstructible</tt>.</td></tr> 4631<tr><td><tt>a_eq.insert(t)</tt></td><td>The <tt>value_type</tt> must be <tt>CopyConstructible</tt>.</td></tr> 4632<tr><td><tt>a_eq.insert(rv)</tt></td><td>The <tt>key_type</tt> and the <tt>mapped_type</tt> (if it exists) must be <tt>MoveConstructible</tt>.</td></tr> 4633<tr><td><tt>a.insert(p, t)</tt></td><td>The <tt>value_type</tt> must be <tt>CopyConstructible</tt>.</td></tr> 4634<tr><td><tt>a.insert(p, rv)</tt></td><td>The <tt>key_type</tt> and the <tt>mapped_type</tt> (if it exists) must be <tt>MoveConstructible</tt>.</td></tr> 4635<tr><td><tt>a.insert(i, j)</tt></td><td>If the iterators return an lvalue the <tt>value_type</tt> must be <tt>CopyConstructible</tt>. 4636 If the iterators return an rvalue the <tt>key_type</tt> and the <tt>mapped_type</tt> (if it exists) must be <tt>MoveConstructible</tt>..</td></tr> 4637</tbody></table> 4638 4639<p> 4640</p> 4641 4642<table border="1"> 4643<caption>Miscellaneous Requirements</caption> 4644<tbody><tr><td><tt>map[lvalue-key]</tt></td><td>The <tt>key_type</tt> must be <tt>CopyConstructible</tt>. 4645 The <tt>mapped_type</tt> must be <tt>DefaultConstructible</tt> and <tt>MoveConstructible</tt>.</td></tr> 4646<tr><td><tt>map[rvalue-key]</tt></td><td>The <tt>key_type</tt> must be <tt>MoveConstructible</tt>. 4647 The <tt>mapped_type</tt> must be <tt>DefaultConstructible</tt> and <tt>MoveConstructible</tt>.</td></tr> 4648</tbody></table> 4649 4650<p><i>[ 4651Kona (2007): Howard and Alan to update requirements table in issue with emplace signatures. 4652]</i></p> 4653 4654 4655<p><i>[ 4656Bellevue: This should be handled as part of the concepts work. 4657]</i></p> 4658 4659 4660<p><i>[ 46612009-07-20 Reopened by Howard: 4662]</i></p> 4663 4664 4665<blockquote> 4666<p> 4667This is one of the issues that was "solved by concepts" and is now no longer solved. 4668</p> 4669 4670<p> 4671In a nutshell, concepts adopted the "minimum requirements" philosophy outlined 4672in the discussion of this issue, and enforced it. My strong suggestion is that 4673we translate the concepts specification into documentation for the containers. 4674</p> 4675 4676<p> 4677What this means for vendors is that they will have to implement container members 4678being careful to only use those characteristics of a type that the concepts specification 4679formally allowed. Note that I <em>am not</em> talking about <tt>enable_if</tt>'ing 4680everything. I am simply suggesting that (for example) we tell the vendor he can't call <tt>T's</tt> 4681copy constructor or move constructor within the <tt>emplace</tt> member function, etc. 4682</p> 4683 4684<p> 4685What this means for customers is that they will be able to use types within C++03 4686containers which are sometimes not CopyConstructible, and sometimes not even 4687MoveConstructible, etc. 4688</p> 4689</blockquote> 4690 4691<p><i>[ 46922009-10 Santa Cruz: 4693]</i></p> 4694 4695 4696<blockquote> 4697Leave open. Howard to provide wording. 4698</blockquote> 4699 4700 4701 4702<p><b>Proposed resolution:</b></p> 4703 4704 4705 4706<p><b>Rationale:</b></p> 4707<p><i>[ 4708post San Francisco: 4709]</i></p> 4710 4711 4712<blockquote> 4713Solved by 4714<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2776.pdf">N2776</a>. 4715</blockquote> 4716 4717 4718 4719 4720 4721 4722<hr> 4723<h3><a name="724"></a>724. <tt>DefaultConstructible</tt> is not defined</h3> 4724<p><b>Section:</b> 20.2.1 [utility.arg.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 4725 <b>Submitter:</b> Pablo Halpern <b>Opened:</b> 2007-09-12 <b>Last modified:</b> 2009-10-23</p> 4726<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#utility.arg.requirements">active issues</a> in [utility.arg.requirements].</p> 4727<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#utility.arg.requirements">issues</a> in [utility.arg.requirements].</p> 4728<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 4729<p><b>Discussion:</b></p> 4730<p> 4731The <tt>DefaultConstructible</tt> requirement is referenced in 4732several places in the August 2007 working draft 4733<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2369.pdf">N2369</a>, 4734but is not defined anywhere. 4735</p> 4736 4737<p><i>[ 4738Bellevue: 4739]</i></p> 4740 4741 4742<blockquote> 4743<p> 4744Walking into the default/value-initialization mess... 4745</p> 4746<p> 4747Why two lines? Because we need both expressions to be valid. 4748</p> 4749<p> 4750AJM not sure what the phrase "default constructed" means. This is 4751unfortunate, as the phrase is already used 24 times in the library! 4752</p> 4753<p> 4754Example: const int would not accept first line, but will accept the second. 4755</p> 4756<p> 4757This is an issue that must be solved by concepts, but we might need to solve it independantly first. 4758</p> 4759<p> 4760It seems that the requirements are the syntax in the proposed first 4761column is valid, but not clear what semantics we need. 4762</p> 4763<p> 4764A table where there is no post-condition seems odd, but appears to sum up our position best. 4765</p> 4766<p> 4767At a minimum an object is declared and is destuctible. 4768</p> 4769<p> 4770Move to open, as no-one happy to produce wording on the fly. 4771</p> 4772</blockquote> 4773 4774<p><i>[ 47752009-07-28 Reopened by Alisdair. No longer solved by concepts. 4776]</i></p> 4777 4778 4779<p><i>[ 47802009-08-17 Daniel adds "[defaultconstructible]" to table title. <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#408">408</a> 4781depends upon this issue. 4782]</i></p> 4783 4784 4785<p><i>[ 47862009-08-18 Alisdair adds: 4787]</i></p> 4788 4789 4790<blockquote> 4791<p> 4792Looking at the proposed table in this issue, it really needs two rows: 4793</p> 4794 4795<blockquote> 4796<table border="1"> 4797<caption>Table 33: <tt>DefaultConstructible</tt> requirements [defaultconstructible]</caption> 4798<tbody><tr> 4799<th>expression</th><th>post-condition</th> 4800</tr> 4801 4802<tr> 4803<td><tt>T t;</tt></td><td><tt>t</tt> is default-initialized.</td> 4804</tr> 4805 4806<tr> 4807<td><tt>T{}</tt></td><td>Object of type <tt>T</tt> is value-initialized.</td> 4808</tr> 4809</tbody></table> 4810</blockquote> 4811 4812<p> 4813Note I am using the new brace-initialization syntax that is unambiguous 4814in all use cases (no most vexing parse.) 4815</p> 4816</blockquote> 4817 4818<p><i>[ 48192009-10-03 Daniel adds: 4820]</i></p> 4821 4822 4823<blockquote> 4824<p> 4825The suggested definition <tt>T{}</tt> describing it as 4826value-initialization is wrong, because it belongs to list-initialization 4827which would - as the current rules are - always prefer a 4828initializer-list constructor over a default-constructor. I don't 4829consider this as an appropriate definition of 4830<tt>DefaultConstructible</tt>. My primary suggestion is to ask core, 4831whether the special case <tt>T{}</tt> (which also easily leads to 4832ambiguity situations for more than one initializer-list in a class) 4833would always prefer a default-constructor - if any - before considering 4834an initializer-list constructor or to provide another syntax form to 4835prefer value-initialization over list-initialization. If that fails I 4836would fall back to suggest to use the expression <tt>T()</tt> instead of 4837<tt>T{}</tt> with all it's disadvantages for the meaning of the 4838expression 4839</p> 4840 4841<blockquote><pre>T t(); 4842</pre></blockquote> 4843</blockquote> 4844 4845<p><i>[ 48462009-10 Santa Cruz: 4847]</i></p> 4848 4849 4850<blockquote> 4851Leave Open. Core is looking to make Alisdair's proposed 4852resolution correct. 4853</blockquote> 4854 4855 4856 4857<p><b>Proposed resolution:</b></p> 4858<p> 4859In section 20.2.1 [utility.arg.requirements], before table 33, add the 4860following table: 4861</p> 4862 4863<p style="text-align: center;" align="center">Table 33: <tt>DefaultConstructible</tt> requirements [defaultconstructible]</p> 4864 4865<div align="center"> 4866 4867<table style="border-collapse: collapse;" border="0" cellpadding="0" cellspacing="0"> 4868 <tbody><tr> 4869 <td style="border-style: solid none double solid; border-color: navy -moz-use-text-color navy navy; border-width: 1pt medium 1.5pt 1pt; padding: 0in 5.4pt; width: 85.5pt;" valign="top" width="114"> 4870 <p style="margin: 0in 0in 0.0001pt; text-align: center;" align="center">expression</p> 4871 </td> 4872 <td style="border-style: solid solid double none; border-color: navy navy navy -moz-use-text-color; border-width: 1pt 1pt 1.5pt medium; padding: 0in 5.4pt; width: 243pt;" valign="top" width="324"> 4873 <p style="margin: 0in 0in 0.0001pt; text-align: center;" align="center">post-condition</p> 4874 </td> 4875 </tr> 4876 <tr> 4877 <td style="border-style: none none solid solid; border-color: -moz-use-text-color -moz-use-text-color navy navy; border-width: medium medium 1pt 1pt; padding: 0in 5.4pt; width: 85.5pt;" valign="top" width="114"> 4878 <p style="margin: 0in 0in 0.0001pt;"><tt>T 4879 t;</tt><br> 4880 <tt>T()</tt></p> 4881 </td> 4882 <td style="border-style: none solid solid none; border-color: -moz-use-text-color navy navy -moz-use-text-color; border-width: medium 1pt 1pt medium; padding: 0in 5.4pt; width: 243pt;" valign="top" width="324"> 4883 <p style="margin: 0in 0in 0.0001pt;"><tt>T</tt> 4884 is <i>default constructed.</i></p> 4885 </td> 4886 </tr> 4887</tbody></table> 4888 4889</div> 4890 4891 4892 4893<p><b>Rationale:</b></p> 4894<p><i>[ 4895San Francisco: 4896]</i></p> 4897 4898<blockquote> 4899We believe concepts will solve this problem 4900(<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2774.pdf">N2774</a>). 4901</blockquote> 4902 4903 4904 4905 4906 4907<hr> 4908<h3><a name="726"></a>726. Missing <tt>regex_replace()</tt> overloads</h3> 4909<p><b>Section:</b> 28.11.4 [re.alg.replace] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 4910 <b>Submitter:</b> Stephan T. Lavavej <b>Opened:</b> 2007-09-22 <b>Last modified:</b> 2009-10-23</p> 4911<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#re.alg.replace">active issues</a> in [re.alg.replace].</p> 4912<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#re.alg.replace">issues</a> in [re.alg.replace].</p> 4913<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 4914<p><b>Discussion:</b></p> 4915<p> 4916Two overloads of <tt>regex_replace()</tt> are currently provided: 4917</p> 4918 4919<blockquote><pre>template <class OutputIterator, class BidirectionalIterator, 4920 class traits, class charT> 4921 OutputIterator 4922 regex_replace(OutputIterator out, 4923 BidirectionalIterator first, BidirectionalIterator last, 4924 const basic_regex<charT, traits>& e, 4925 const basic_string<charT>& fmt, 4926 regex_constants::match_flag_type flags = 4927 regex_constants::match_default); 4928 4929template <class traits, class charT> 4930 basic_string<charT> 4931 regex_replace(const basic_string<charT>& s, 4932 const basic_regex<charT, traits>& e, 4933 const basic_string<charT>& fmt, 4934 regex_constants::match_flag_type flags = 4935 regex_constants::match_default); 4936</pre></blockquote> 4937 4938<ol> 4939<li>Overloads taking <tt>const charT *</tt> are provided for <tt>regex_match()</tt> and 4940<tt>regex_search()</tt>, but not <tt>regex_replace()</tt>. This is inconsistent.</li> 4941<li> 4942<p>The absence of <tt>const charT *</tt> overloads prevents ordinary-looking code from compiling, such as:</p> 4943 4944<blockquote><pre>const string s("kitten"); 4945const regex r("en"); 4946cout << regex_replace(s, r, "y") << endl; 4947</pre></blockquote> 4948 4949<p> 4950The compiler error message will be something like "could not deduce 4951template argument for 'const std::basic_string<_Elem> &' from 'const 4952char[1]'". 4953</p> 4954 4955<p> 4956Users expect that anything taking a <tt>basic_string<charT></tt> can also take a 4957<tt>const charT *</tt>. In their own code, when they write a function taking 4958<tt>std::string</tt> (or <tt>std::wstring</tt>), they can pass a <tt>const char *</tt> (or <tt>const 4959wchar_t *</tt>), thanks to <tt>basic_string</tt>'s implicit constructor. Because the 4960regex algorithms are templated on <tt>charT</tt>, they can't rely on 4961<tt>basic_string</tt>'s implicit constructor (as the compiler error message 4962indicates, template argument deduction fails first). 4963</p> 4964 4965<p> 4966If a user figures out what the compiler error message means, workarounds 4967are available - but they are all verbose. Explicit template arguments 4968could be given to <tt>regex_replace()</tt>, allowing <tt>basic_string</tt>'s implicit 4969constructor to be invoked - but <tt>charT</tt> is the last template argument, not 4970the first, so this would be extremely verbose. Therefore, constructing 4971a <tt>basic_string</tt> from each C string is the simplest workaround. 4972</p> 4973</li> 4974 4975<li> 4976There is an efficiency consideration: constructing <tt>basic_string</tt>s can 4977impose performance costs that could be avoided by a library 4978implementation taking C strings and dealing with them directly. 4979(Currently, for replacement sources, C strings can be converted into 4980iterator pairs at the cost of verbosity, but for format strings, there 4981is no way to avoid constructing a <tt>basic_string</tt>.) 4982</li> 4983</ol> 4984 4985<p><i>[ 4986Sophia Antipolis: 4987]</i></p> 4988 4989 4990<blockquote> 4991We note that Boost already has these overloads. However, the proposed 4992wording is provided only for 28.11.4 [re.alg.replace]; wording is needed for the synopsis 4993as well. We also note that this has impact on <tt>match_results::format</tt>, 4994which may require further overloads. 4995</blockquote> 4996 4997<p><i>[ 49982009-07 Frankfurt: 4999]</i></p> 5000 5001 5002<blockquote> 5003Daniel to tweak for us. 5004</blockquote> 5005 5006<p><i>[ 50072009-07-25 Daniel tweaks both this issue and <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#727">727</a>. 5008]</i></p> 5009 5010 5011<blockquote> 5012<p> 5013This is solved by the proposed resolution of <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#727">727</a>. 5014</p> 5015</blockquote> 5016 5017<p><i>[ 50182009-10 Santa Cruz: 5019]</i></p> 5020 5021 5022<blockquote> 5023Leave Open. Though we believe this is solved by the proposed resolution 5024to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#727">727</a>. 5025</blockquote> 5026 5027 5028 5029<p><b>Proposed resolution:</b></p> 5030 5031<p> 5032Provide additional overloads for <tt>regex_replace()</tt>: one additional 5033overload of the iterator-based form (taking <tt>const charT* fmt</tt>), and three 5034additional overloads of the convenience form (one taking <tt>const charT* 5035str</tt>, another taking <tt>const charT* fmt</tt>, and the third taking both <tt>const 5036charT* str</tt> and <tt>const charT* fmt</tt>). 28.11.4 [re.alg.replace]: 5037</p> 5038 5039<blockquote> 5040<pre>template <class OutputIterator, class BidirectionalIterator, 5041 class traits, class charT> 5042 OutputIterator 5043 regex_replace(OutputIterator out, 5044 BidirectionalIterator first, BidirectionalIterator last, 5045 const basic_regex<charT, traits>& e, 5046 const basic_string<charT>& fmt, 5047 regex_constants::match_flag_type flags = 5048 regex_constants::match_default); 5049 5050<ins>template <class OutputIterator, class BidirectionalIterator, 5051 class traits, class charT> 5052 OutputIterator 5053 regex_replace(OutputIterator out, 5054 BidirectionalIterator first, BidirectionalIterator last, 5055 const basic_regex<charT, traits>& e, 5056 const charT* fmt, 5057 regex_constants::match_flag_type flags = 5058 regex_constants::match_default);</ins> 5059</pre> 5060<p>...</p> 5061<pre>template <class traits, class charT> 5062 basic_string<charT> 5063 regex_replace(const basic_string<charT>& s, 5064 const basic_regex<charT, traits>& e, 5065 const basic_string<charT>& fmt, 5066 regex_constants::match_flag_type flags = 5067 regex_constants::match_default); 5068 5069<ins>template <class traits, class charT> 5070 basic_string<charT> 5071 regex_replace(const basic_string<charT>& s, 5072 const basic_regex<charT, traits>& e, 5073 const charT* fmt, 5074 regex_constants::match_flag_type flags = 5075 regex_constants::match_default);</ins> 5076 5077<ins>template <class traits, class charT> 5078 basic_string<charT> 5079 regex_replace(const charT* s, 5080 const basic_regex<charT, traits>& e, 5081 const basic_string<charT>& fmt, 5082 regex_constants::match_flag_type flags = 5083 regex_constants::match_default);</ins> 5084 5085<ins>template <class traits, class charT> 5086 basic_string<charT> 5087 regex_replace(const charT* s, 5088 const basic_regex<charT, traits>& e, 5089 const charT* fmt, 5090 regex_constants::match_flag_type flags = 5091 regex_constants::match_default);</ins> 5092</pre> 5093</blockquote> 5094 5095 5096 5097 5098 5099 5100<hr> 5101<h3><a name="727"></a>727. <tt>regex_replace()</tt> doesn't accept <tt>basic_string</tt>s with custom traits and allocators</h3> 5102<p><b>Section:</b> 28.11.4 [re.alg.replace] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Review">Review</a> 5103 <b>Submitter:</b> Stephan T. Lavavej <b>Opened:</b> 2007-09-22 <b>Last modified:</b> 2009-10-23</p> 5104<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#re.alg.replace">active issues</a> in [re.alg.replace].</p> 5105<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#re.alg.replace">issues</a> in [re.alg.replace].</p> 5106<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Review">Review</a> status.</p> 5107<p><b>Discussion:</b></p> 5108<p> 5109<tt>regex_match()</tt> and <tt>regex_search()</tt> take <tt>const basic_string<charT, ST, 5110SA>&</tt>. <tt>regex_replace()</tt> takes <tt>const basic_string<charT>&</tt>. This prevents 5111<tt>regex_replace()</tt> from accepting <tt>basic_string</tt>s with custom traits and 5112allocators. 5113</p> 5114 5115<p> 5116Overloads of <tt>regex_replace()</tt> taking <tt>basic_string</tt> should be additionally 5117templated on <tt>class ST, class SA</tt> and take <tt>const basic_string<charT, ST, 5118SA>&</tt>. Consistency with <tt>regex_match()</tt> and <tt>regex_search()</tt> would place 5119<tt>class ST, class SA</tt> as the first template arguments; compatibility with 5120existing code using TR1 and giving explicit template arguments to 5121<tt>regex_replace()</tt> would place <tt>class ST, class SA</tt> as the last template 5122arguments. 5123</p> 5124 5125<p><i>[ 5126Batavia (2009-05): 5127]</i></p> 5128 5129<blockquote> 5130<p> 5131Bill comments, "We need to look at the depth of this change." 5132</p> 5133<p> 5134Pete remarks that we are here dealing with a convenience function 5135that saves a user from calling the iterato-based overload. 5136</p> 5137<p> 5138Move to Open. 5139</p> 5140</blockquote> 5141 5142<p><i>[ 51432009-07 Frankfurt: 5144]</i></p> 5145 5146 5147<blockquote> 5148Howard to ask Stephan Lavavej to provide wording. 5149</blockquote> 5150 5151<p><i>[ 51522009-07-17 Stephan provided wording. 5153]</i></p> 5154 5155 5156<p><i>[ 51572009-07-25 Daniel tweaks both this issue and <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#726">726</a>. 5158]</i></p> 5159 5160 5161<blockquote> 5162<p> 5163One relevant part of the proposed resolution below suggests 5164to add a new overload of the format member function in the 5165<tt>match_results</tt> class template that accepts two character pointers 5166defining the <tt>begin</tt> and <tt>end</tt> of a format range. A more general 5167approach could have proposed a pair of iterators instead, but 5168the used pair of char pointers reflects existing practice. If the 5169committee strongly favors an iterator-based signature, this 5170could be simply changed. I think that the minimum requirement 5171should be a <tt>BidirectionalIterator</tt>, but current implementations 5172take advantage (at least partially) of the <tt>RandomAccessIterator</tt> 5173sub interface of the char pointers. 5174</p> 5175 5176<p><b>Suggested Resolution:</b></p> 5177 5178<p><i>[Moved into the proposed resloution]</i></p> 5179 5180 5181 5182</blockquote> 5183 5184<p><i>[ 51852009-07-30 Stephan agrees with Daniel's wording. Howard places Daniel's wording 5186in the Proposed Resolution. 5187]</i></p> 5188 5189 5190<p><i>[ 51912009-10 Santa Cruz: 5192]</i></p> 5193 5194 5195<blockquote> 5196Move to Review. Chair is anxious to move this to Ready in Pittsburgh. 5197</blockquote> 5198 5199 5200 5201<p><b>Proposed resolution:</b></p> 5202 5203<ol> 5204<li> 5205<p> 5206Change 28.4 [re.syn] as indicated: 5207</p> 5208 5209<blockquote><pre>// 28.11.4, function template regex_replace: 5210template <class OutputIterator, class BidirectionalIterator, 5211 class traits, class charT<ins>, class ST, class SA</ins>> 5212 OutputIterator 5213 regex_replace(OutputIterator out, 5214 BidirectionalIterator first, BidirectionalIterator last, 5215 const basic_regex<charT, traits>& e, 5216 const basic_string<charT<ins>, ST, SA</ins>>& fmt, 5217 regex_constants::match_flag_type flags = 5218 regex_constants::match_default); 5219 5220<ins> 5221template <class OutputIterator, class BidirectionalIterator, 5222 class traits, class charT> 5223 OutputIterator 5224 regex_replace(OutputIterator out, 5225 BidirectionalIterator first, BidirectionalIterator last, 5226 const basic_regex<charT, traits>& e, 5227 const charT* fmt, 5228 regex_constants::match_flag_type flags = 5229 regex_constants::match_default); 5230</ins> 5231 5232template <class traits, class charT<ins>, class ST, class SA, 5233 class FST, class FSA</ins>> 5234 basic_string<charT<ins>, ST, SA</ins>> 5235 regex_replace(const basic_string<charT<ins>, ST, SA</ins>>& s, 5236 const basic_regex<charT, traits>& e, 5237 const basic_string<charT<ins>, FST, FSA</ins>>& fmt, 5238 regex_constants::match_flag_type flags = 5239 regex_constants::match_default); 5240 5241<ins> 5242template <class traits, class charT, class ST, class SA> 5243 basic_string<charT, ST, SA> 5244 regex_replace(const basic_string<charT, ST, SA>& s, 5245 const basic_regex<charT, traits>& e, 5246 const charT* fmt, 5247 regex_constants::match_flag_type flags = 5248 regex_constants::match_default); 5249</ins> 5250 5251<ins> 5252template <class traits, class charT, class ST, class SA> 5253 basic_string<charT> 5254 regex_replace(const charT* s, 5255 const basic_regex<charT, traits>& e, 5256 const basic_string<charT, ST, SA>& fmt, 5257 regex_constants::match_flag_type flags = 5258 regex_constants::match_default); 5259</ins> 5260 5261<ins> 5262template <class traits, class charT> 5263 basic_string<charT> 5264 regex_replace(const charT* s, 5265 const basic_regex<charT, traits>& e, 5266 const charT* fmt, 5267 regex_constants::match_flag_type flags = 5268 regex_constants::match_default); 5269</ins> 5270</pre></blockquote> 5271</li> 5272 5273<li> 5274<p> 5275Change 28.10 [re.results]/3, class template <tt>match_results</tt> as 5276indicated: 5277</p> 5278 5279<blockquote><pre><ins> 5280template <class OutputIter> 5281 OutputIter 5282 format(OutputIter out, 5283 const char_type* fmt_first, const char_type* fmt_last, 5284 regex_constants::match_flag_type flags = 5285 regex_constants::format_default) const; 5286</ins> 5287 5288template <class OutputIter<ins>, class ST, class SA</ins>> 5289 OutputIter 5290 format(OutputIter out, 5291 const <del>string_type</del><ins>basic_string<char_type, ST, SA></ins>& fmt, 5292 regex_constants::match_flag_type flags = 5293 regex_constants::format_default) const; 5294 5295<ins>template <class ST, class SA></ins> 5296 <del>string_type</del><ins>basic_string<char_type, ST, SA></ins> 5297 format(const <del>string_type</del><ins>basic_string<char_type, ST, SA></ins>& fmt, 5298 regex_constants::match_flag_type flags = 5299 regex_constants::format_default) const; 5300 5301<ins> 5302string_type 5303format(const char_type* fmt, 5304 regex_constants::match_flag_type flags = 5305 regex_constants::format_default) const; 5306</ins> 5307</pre></blockquote> 5308</li> 5309 5310<li> 5311<p> 5312Insert at the very beginning of 28.10.4 [re.results.form] the following: 5313</p> 5314 5315<blockquote><pre><ins> 5316template <class OutputIter> 5317 OutputIter 5318 format(OutputIter out, 5319 const char_type* fmt_first, const char_type* fmt_last, 5320 regex_constants::match_flag_type flags = 5321 regex_constants::format_default) const; 5322</ins> 5323</pre> 5324<blockquote> 5325 5326<p><ins> 53271 <i>Requires:</i> The type <tt>OutputIter</tt> shall satisfy the requirements for an 5328Output Iterator (24.2.2 [output.iterators]). 5329</ins></p> 5330 5331<p><ins> 53322 <i>Effects:</i> Copies the character sequence <tt>[fmt_first,fmt_last)</tt> to 5333<tt>OutputIter out</tt>. Replaces each 5334format specifier or escape sequence in the copied range with either 5335the character(s) it represents 5336or the sequence of characters within <tt>*this</tt> to which it refers. The 5337bitmasks specified in <tt>flags</tt> 5338determines what format specifiers and escape sequences are recognized. 5339</ins></p> 5340 5341<p><ins> 53423 <i>Returns:</i> <tt>out</tt>. 5343</ins></p> 5344</blockquote> 5345</blockquote> 5346</li> 5347 5348<li> 5349<p> 5350Change 28.10.4 [re.results.form], before p. 1 until p. 3 (according to 5351previous numbering) 5352as indicated: 5353</p> 5354 5355<blockquote><pre>template <class OutputIter<ins>, class ST, class SA</ins>> 5356 OutputIter 5357 format(OutputIter out, 5358 const <del>string_type</del><ins>basic_string<char_type, ST, SA></ins>& fmt, 5359 regex_constants::match_flag_type flags = 5360 regex_constants::format_default) const; 5361</pre> 5362 5363<blockquote> 5364<p> 5365<del><i>Requires:</i> The type <tt>OutputIter</tt> shall satisfy the requirements for 5366an Output Iterator (24.2.3).</del> 5367</p> 5368 5369<p> 5370<del><i>Effects:</i> Copies the character sequence <tt>[fmt.begin(),fmt.end())</tt> to 5371<tt>OutputIter out</tt>. Replaces each 5372format specifier or escape sequence in <tt>fmt</tt> with either the 5373character(s) it represents or the sequence of 5374characters within <tt>*this</tt> to which it refers. The bitmasks specified in 5375<tt>flags</tt> determines what format 5376specifiers and escape sequences are recognized.</del> 5377</p> 5378 5379<p> 5380<i>Returns:</i> <tt><del>out</del><ins>format(out, fmt.data(), fmt.data() + 5381fmt.size(), flags)</ins></tt>. 5382</p> 5383</blockquote> 5384</blockquote> 5385</li> 5386 5387<li> 5388<p> 5389Change 28.10.4 [re.results.form], before p. 4 until p. 4 (according to 5390previous numbering) as indicated: 5391</p> 5392 5393<blockquote><pre><ins>template <class ST, class SA></ins> 5394 <del>string_type</del><ins>basic_string<char_type, ST, SA></ins> 5395 format(const <del>string_type</del><ins>basic_string<char_type, ST, SA></ins>& fmt, 5396 regex_constants::match_flag_type flags = 5397 regex_constants::format_default) const; 5398</pre> 5399 5400<blockquote> 5401<p> 5402<i>Effects:</i> <del>Returns a copy of the string <tt>fmt</tt>. Replaces each format 5403specifier or escape sequence 5404in <tt>fmt</tt> with either the character(s) it represents or the sequence of 5405characters within <tt>*this</tt> to which 5406it refers. The bitmasks specified in flags determines what format 5407specifiers and escape sequences are 5408recognized.</del> <ins>Constructs an empty string <tt>result</tt> of type 5409<tt>basic_string<char_type, ST, SA></tt>, 5410and calls <tt>format(back_inserter(result), fmt, flags)</tt>.</ins> 5411</p> 5412 5413<p> 5414<ins><i>Returns:</i> <tt>result</tt></ins> 5415</p> 5416</blockquote> 5417</blockquote> 5418</li> 5419 5420<li> 5421<p> 5422At the end of 28.10.4 [re.results.form] insert as indicated: 5423</p> 5424 5425<blockquote><pre><ins> 5426string_type 5427 format(const char_type* fmt, 5428 regex_constants::match_flag_type flags = 5429 regex_constants::format_default) const; 5430</ins></pre> 5431 5432<blockquote> 5433<p> 5434<ins><i>Effects:</i> Constructs an empty string <tt>result</tt> of type <tt>string_type</tt>, and calls 5435<tt>format(back_inserter(result), fmt, fmt + 5436char_traits<char_type>::length(fmt), flags)</tt>.</ins> 5437</p> 5438<p> 5439<ins><i>Returns:</i> <tt>result</tt></ins> 5440</p> 5441</blockquote> 5442</blockquote> 5443 5444</li> 5445 5446<li> 5447<p> 5448Change 28.11.4 [re.alg.replace] before p. 1 as indicated: 5449</p> 5450 5451<blockquote><pre>template <class OutputIterator, class BidirectionalIterator, 5452 class traits, class charT<ins>, class ST, class SA</ins>> 5453 OutputIterator 5454 regex_replace(OutputIterator out, 5455 BidirectionalIterator first, BidirectionalIterator last, 5456 const basic_regex<charT, traits>& e, 5457 const basic_string<charT<ins>, ST, SA</ins>>& fmt, 5458 regex_constants::match_flag_type flags = 5459 regex_constants::match_default); 5460 5461<ins> 5462template <class OutputIterator, class BidirectionalIterator, 5463 class traits, class charT> 5464 OutputIterator 5465 regex_replace(OutputIterator out, 5466 BidirectionalIterator first, BidirectionalIterator last, 5467 const basic_regex<charT, traits>& e, 5468 const charT* fmt, 5469 regex_constants::match_flag_type flags = 5470 regex_constants::match_default); 5471</ins></pre> 5472 5473<blockquote> 5474<i>Effects:</i> [..]. If any matches are found then, for each such match, if <tt>!(flags & 5475 regex_constants::format_no_copy)</tt> calls <tt>std::copy(m.prefix().first, 5476m.prefix().second, 5477 out)</tt>, and then calls <tt>m.format(out, fmt, flags)</tt> <ins>for the first 5478form of the function 5479 and <tt>m.format(out, fmt, fmt + char_traits<charT>::length(fmt), flags)</tt> 5480for the second 5481 form</ins>. [..]. 5482</blockquote> 5483</blockquote> 5484</li> 5485 5486<li> 5487<p> 5488Change 28.11.4 [re.alg.replace] before p. 3 as indicated: 5489</p> 5490 5491<blockquote><pre>template <class traits, class charT<ins>, class ST, class SA, 5492 class FST, class FSA</ins>> 5493 basic_string<charT<ins>, ST, SA</ins>> 5494 regex_replace(const basic_string<charT<ins>, ST, SA</ins>>& s, 5495 const basic_regex<charT, traits>& e, 5496 const basic_string<charT<ins>, FST, FSA</ins>>& fmt, 5497 regex_constants::match_flag_type flags = 5498 regex_constants::match_default); 5499 5500<ins> 5501template <class traits, class charT, class ST, class SA> 5502 basic_string<charT, ST, SA> 5503 regex_replace(const basic_string<charT, ST, SA>& s, 5504 const basic_regex<charT, traits>& e, 5505 const charT* fmt, 5506 regex_constants::match_flag_type flags = 5507 regex_constants::match_default); 5508</ins></pre> 5509 5510<blockquote> 5511<i>Effects:</i> Constructs an empty string <tt>result</tt> of type <tt>basic_string<charT<ins>, 5512ST, SA</ins>></tt>, calls <tt>regex_replace(back_inserter(result), s.begin(), s.end(), 5513e, fmt, flags)</tt>, and then returns <tt>result</tt>. 5514</blockquote> 5515</blockquote> 5516</li> 5517 5518<li> 5519<p> 5520At the end of 28.11.4 [re.alg.replace] add the following new prototype description: 5521</p> 5522 5523<blockquote><pre><ins> 5524template <class traits, class charT, class ST, class SA> 5525 basic_string<charT> 5526 regex_replace(const charT* s, 5527 const basic_regex<charT, traits>& e, 5528 const basic_string<charT, ST, SA>& fmt, 5529 regex_constants::match_flag_type flags = 5530 regex_constants::match_default); 5531</ins> 5532 5533<ins> 5534template <class traits, class charT> 5535 basic_string<charT> 5536 regex_replace(const charT* s, 5537 const basic_regex<charT, traits>& e, 5538 const charT* fmt, 5539 regex_constants::match_flag_type flags = 5540 regex_constants::match_default); 5541</ins></pre> 5542 5543<blockquote> 5544<ins> 5545<i>Effects:</i> Constructs an empty string <tt>result</tt> of type <tt>basic_string<charT></tt>, 5546calls <tt>regex_replace(back_inserter(result), s, s + 5547char_traits<charT>::length(s), 5548e, fmt, flags)</tt>, and then returns <tt>result</tt>. 5549</ins> 5550</blockquote> 5551</blockquote> 5552</li> 5553 5554</ol> 5555 5556 5557 5558 5559 5560 5561 5562<hr> 5563<h3><a name="742"></a>742. Enabling <tt>swap</tt> for proxy iterators</h3> 5564<p><b>Section:</b> 20.2.1 [utility.arg.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 5565 <b>Submitter:</b> Howard Hinnant <b>Opened:</b> 2007-10-10 <b>Last modified:</b> 2009-11-08</p> 5566<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#utility.arg.requirements">active issues</a> in [utility.arg.requirements].</p> 5567<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#utility.arg.requirements">issues</a> in [utility.arg.requirements].</p> 5568<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 5569<p><b>Discussion:</b></p> 5570<p> 5571This issue was split from <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#672">672</a>. <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#672">672</a> now just 5572deals with changing the requirements of <tt>T</tt> in the <tt>Swappable</tt> 5573requirement from <tt>CopyConstructible</tt> and <tt>CopyAssignable</tt> to 5574<tt>MoveConstructible</tt> and <tt>MoveAssignable</tt>. 5575</p> 5576 5577<p> 5578This issue seeks to widen the <tt>Swappable</tt> requirement to support proxy iterators. Here 5579is example code: 5580</p> 5581 5582<blockquote><pre>namespace Mine { 5583 5584template <class T> 5585struct proxy {...}; 5586 5587template <class T> 5588struct proxied_iterator 5589{ 5590 typedef T value_type; 5591 typedef proxy<T> reference; 5592 reference operator*() const; 5593 ... 5594}; 5595 5596struct A 5597{ 5598 // heavy type, has an optimized swap, maybe isn't even copyable or movable, just swappable 5599 void swap(A&); 5600 ... 5601}; 5602 5603void swap(A&, A&); 5604void swap(proxy<A>, A&); 5605void swap(A&, proxy<A>); 5606void swap(proxy<A>, proxy<A>); 5607 5608} // Mine 5609 5610... 5611 5612Mine::proxied_iterator<Mine::A> i(...) 5613Mine::A a; 5614<b>swap(*i1, a);</b> 5615</pre></blockquote> 5616 5617<p> 5618The key point to note in the above code is that in the call to <tt>swap</tt>, <tt>*i1</tt> 5619and <tt>a</tt> are different types (currently types can only be <tt>Swappable</tt> with the 5620same type). A secondary point is that to support proxies, one must be able to pass rvalues 5621to <tt>swap</tt>. But note that I am not stating that the general purpose <tt>std::swap</tt> 5622should accept rvalues! Only that overloaded <tt>swap</tt>s, as in the example above, be allowed 5623to take rvalues. 5624</p> 5625 5626<p> 5627That is, no standard library code needs to change. We simply need to have a more flexible 5628definition of <tt>Swappable</tt>. 5629</p> 5630 5631<p><i>[ 5632Bellevue: 5633]</i></p> 5634 5635 5636<blockquote> 5637<p> 5638While we believe Concepts work will define a swappable concept, we 5639should still resolve this issue if possible to give guidance to the 5640Concepts work. 5641</p> 5642<p> 5643Would an ambiguous swap function in two namespaces found by ADL break 5644this wording? Suggest that the phrase "valid expression" means such a 5645pair of types would still not be swappable. 5646</p> 5647<p> 5648Motivation is proxy-iterators, but facility is considerably more 5649general. Are we happy going so far? 5650</p> 5651<p> 5652We think this wording is probably correct and probably an improvement on 5653what's there in the WP. On the other hand, what's already there in the 5654WP is awfully complicated. Why do we need the two bullet points? They're 5655too implementation-centric. They don't add anything to the semantics of 5656what swap() means, which is there in the post-condition. What's wrong 5657with saying that types are swappable if you can call swap() and it 5658satisfies the semantics of swapping? 5659</p> 5660</blockquote> 5661 5662<p><i>[ 56632009-07-28 Reopened by Alisdair. No longer solved by concepts. 5664]</i></p> 5665 5666 5667<p><i>[ 56682009-10 Santa Cruz: 5669]</i></p> 5670 5671 5672<blockquote> 5673Leave as Open. Dave to provide wording. 5674</blockquote> 5675 5676<p><i>[ 56772009-11-08 Howard adds: 5678]</i></p> 5679 5680 5681<blockquote> 5682Updated wording to sync with 5683<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n3000.pdf">N3000</a>. 5684Also this issue is very closely related to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#594">594</a>. 5685</blockquote> 5686 5687 5688 5689<p><b>Proposed resolution:</b></p> 5690<p> 5691Change 20.2.1 [utility.arg.requirements]: 5692</p> 5693 5694<blockquote> 5695 5696<p> 5697-1- The template definitions in the C++ Standard Library refer to various 5698named requirements whose details are set out in tables 31-38. In these 5699tables, <tt>T</tt> <ins>and <tt>V</tt> are</ins> <del>is a</del> type<ins>s</ins> to be supplied by a C++ program 5700instantiating a template; <tt>a</tt>, <tt>b</tt>, and <tt>c</tt> are 5701values of type <tt>const T</tt>; <tt>s</tt> and <tt>t</tt> are modifiable 5702lvalues of type <tt>T</tt>; <tt>u</tt> is a value of type (possibly 5703<tt>const</tt>) <tt>T</tt>; <del>and</del> <tt>rv</tt> is a non-<tt>const</tt> 5704rvalue of type <tt>T</tt><ins>; <tt>w</tt> is a value of type <tt>T</tt>; and <tt>v</tt> is a value of type <tt>V</tt></ins>. 5705</p> 5706 5707<table border="1"> 5708<caption>Table 37: <tt>Swappable</tt> requirements <b>[swappable]</b></caption> 5709<tbody><tr><th>expression</th><th>Return type</th><th>Post-condition</th></tr> 5710<tr><td><tt>swap(<del>s</del><ins>w</ins>,<del>t</del><ins>v</ins>)</tt></td><td><tt>void</tt></td> 5711<td><del><tt>t</tt></del><ins><tt>w</tt></ins> has the value originally 5712held by <del><tt>u</tt></del><ins><tt>v</tt></ins>, and 5713<del><tt>u</tt></del><ins><tt>v</tt></ins> has the value originally held 5714by <del><tt>t</tt></del><ins><tt>w</tt></ins></td></tr> 5715<tr><td colspan="3"> 5716<p> 5717The <tt>Swappable</tt> requirement is met by satisfying one or more of the following conditions: 5718</p> 5719<ul> 5720<li> 5721<tt>T</tt> is <tt>Swappable</tt> if <ins><tt>T</tt> and <tt>V</tt> are 5722the same type and </ins> <tt>T</tt> satisfies the 5723<tt>MoveConstructible</tt> requirements (Table 572433) and the 5725<tt>MoveAssignable</tt> requirements (Table 572635); 5727</li> 5728<li> 5729<tt>T</tt> is <tt>Swappable</tt> <ins>with <tt>V</tt></ins> if a namespace scope function named 5730<tt>swap</tt> exists in the same namespace as the definition of 5731<tt>T</tt> <ins>or <tt>V</tt></ins>, such that the expression 5732<tt>swap(<del>s</del><ins>w</ins>,<del>t</del> <ins>v</ins>)</tt> is valid and has the 5733semantics described in this table. 5734</li> 5735<li> 5736<tt>T</tt> is <tt>Swappable</tt> if <tt>T</tt> is an array type whose 5737element type is <tt>Swappable</tt>. 5738</li> 5739</ul> 5740</td></tr> 5741</tbody></table> 5742</blockquote> 5743 5744 5745 5746<p><b>Rationale:</b></p> 5747<p><i>[ 5748post San Francisco: 5749]</i></p> 5750 5751 5752<blockquote> 5753Solved by 5754<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2758.pdf">N2758</a>. 5755</blockquote> 5756 5757 5758 5759 5760 5761 5762<hr> 5763<h3><a name="774"></a>774. Member swap undefined for most containers</h3> 5764<p><b>Section:</b> 23 [containers] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 5765 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2008-01-14 <b>Last modified:</b> 2009-10-31</p> 5766<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#containers">active issues</a> in [containers].</p> 5767<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#containers">issues</a> in [containers].</p> 5768<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 5769<p><b>Discussion:</b></p> 5770<p> 5771It appears most containers declare but do not define a member-swap 5772function. 5773</p> 5774 5775<p> 5776This is unfortunate, as all overload the <tt>swap</tt> algorithm to call the 5777member-swap function! 5778(required for <tt>swappable</tt> guarantees [Table 37] and Container Requirements 5779[Table 87]) 5780</p> 5781 5782<p> 5783Note in particular that Table 87 gives semantics of <tt>a.swap(b)</tt> as <tt>swap(a,b)</tt>, 5784yet for all containers we define <tt>swap(a,b)</tt> to call <tt>a.swap(b)</tt> - a circular 5785definition. 5786</p> 5787 5788<p> 5789A quick survey of clause 23 shows that the following containers provide a 5790definition for member-swap: 5791</p> 5792 5793<blockquote><pre>array 5794queue 5795stack 5796vector 5797</pre></blockquote> 5798 5799<p> 5800Whereas the following declare it, but do not define the semantics: 5801</p> 5802 5803<blockquote><pre>deque 5804list 5805map 5806multimap 5807multiset 5808priority_queue 5809set 5810unordered_map 5811unordered_multi_map 5812unordered_multi_set 5813unordered_set 5814</pre></blockquote> 5815 5816<p> 5817Suggested resolution: 5818</p> 5819<blockquote> 5820Provide a definition for each of the affected containers... 5821</blockquote> 5822 5823<p><i>[ 5824Bellevue: 5825]</i></p> 5826 5827 5828<blockquote> 5829Move to Open and ask Alisdair to provide wording. 5830</blockquote> 5831 5832<p><i>[ 58332009-07 Frankfurt: 5834]</i></p> 5835 5836 5837<blockquote> 5838Daniel to provide wording. 5839<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2590.pdf">N2590</a> 5840is no longer applicable. 5841</blockquote> 5842 5843<p><i>[ 58442009-07-28 Daniel provided wording. 5845]</i></p> 5846 5847 5848<blockquote> 5849<ol> 5850<li> 5851It assumes that the proposed resolution for <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#883">883</a> is applied, 5852which breaks the circularity of definition between member 5853<tt>swap</tt> and free <tt>swap</tt>. 5854</li> 5855 5856<li> 5857It uses the notation of the pre-concept allocator trait 5858<tt>allocator_propagation_map</tt>, which might be renamed after the 5859next refactoring phase of generalized allocators. 5860</li> 5861 5862<li> 5863It requires that compare objects, key equal functions and 5864hash functions in containers are swapped via unqualified free 5865<tt>swap</tt> according to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#594">594</a>. 5866</li> 5867</ol> 5868</blockquote> 5869 5870<p><i>[ 58712009-09-30 Daniel adds: 5872]</i></p> 5873 5874 5875<blockquote> 5876The outcome of this issue should be considered with the outcome of <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1198">1198</a> both in style and in content (e.g. bullet 9 suggests to 5877define the semantic of <tt>void 5878priority_queue::swap(priority_queue&)</tt> in terms of the member 5879<tt>swap</tt> of the container). 5880</blockquote> 5881 5882<p><i>[ 58832009-10 Santa Cruz: 5884]</i></p> 5885 5886 5887<blockquote> 5888Looked at, but took no action on as it overlaps too much with 5889<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2982.pdf">N2982</a>. 5890Waiting for a new draft WP. 5891</blockquote> 5892 5893<p><i>[ 58942009-10 Santa Cruz: 5895]</i></p> 5896 5897 5898<blockquote> 5899Leave as open. Pablo to provide wording. 5900</blockquote> 5901 5902<p><i>[ 59032009-10-26 Pablo updated wording. Here is the wording he replaced: 5904]</i></p> 5905 5906 5907<blockquote class="note"> 5908<ol> 5909<li> 5910<p> 5911Add a new Throws clause just after X [allocator.propagation.map]/5: 5912</p> 5913 5914<blockquote><pre>static void swap(Alloc& a, Alloc& b); 5915</pre> 5916<blockquote> 5917<p> 5918<i>Effects:</i> [..] 5919</p> 5920 5921<p> 5922<ins><i>Throws:</i> Nothing.</ins> 5923</p> 5924</blockquote> 5925</blockquote> 5926<p><i>[ 5927This exception requirement is added, such that it's combination with the 5928general container requirements of 5929<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2723.pdf">N2723</a> 5930[container.requirements.general]/9 5931make it unambiguously clear that the following descriptions of "swaps the 5932allocators" have the following meaning: (a) This swap is done by calling 5933<tt>allocator_propagation_map<allocator_type>::swap</tt> and (b) This allocator 5934swap does never propagate an exception 5935]</i></p> 5936 5937</li> 5938 5939<li> 5940<p> 5941Change 23.2.4.1 [associative.reqmts.except]/3 as indicated: 5942</p> 5943 5944<blockquote> 5945For associative containers, no <tt>swap</tt> function throws an exception unless that 5946exception is thrown by the <del>copy constructor or copy assignment 5947operator</del> 5948<ins><tt>swap</tt></ins> of the container's <tt>Pred</tt> object<ins>s</ins><del> (if any)</del>. 5949</blockquote> 5950</li> 5951 5952<li> 5953<p> 5954Change 23.2.5.1 [unord.req.except]/3 as indicated: 5955</p> 5956 5957<blockquote> 5958For unordered associative containers, no <tt>swap</tt> function throws an 5959exception unless 5960that exception is thrown by the <del>copy constructor or copy 5961assignment operator</del> 5962<ins><tt>swap</tt></ins> of the container's <tt>Hash</tt> or <tt>Pred</tt> object<ins>s, 5963respectively</ins><del> (if any)</del>. 5964</blockquote> 5965</li> 5966 5967<li> 5968<p> 5969Insert a new paragraph just after 23.3 [sequences]/1: 5970</p> 5971 5972<blockquote> 5973<ins>In addition to being available via inclusion of the <tt><algorithm></tt> header, 5974the <tt>swap</tt> function templates in 25.3.3 [alg.swap] are also available when the 5975header <tt><queue></tt> is included.</ins> 5976</blockquote> 5977 5978<p><i>[ 5979There is a new issue in process that will suggest a minimum header for <tt>swap</tt> 5980and <tt>move</tt>. If this one is provided, this text can be removed and the header 5981dependency should be added to <tt><queue></tt> 5982]</i></p> 5983 5984 5985</li> 5986 5987<li> 5988<p> 5989Add one further clause at the end of 23.3.1.2 [array.special]: 5990</p> 5991<p><i>[This part is added, because otherwise <tt>array::swap</tt> would otherwise 5992contradict the 5993general contract of 23.2.1 [container.requirements.general] p. 10 b. 5]</i></p> 5994 5995 5996<blockquote> 5997<ins><i>Throws:</i> Nothing, unless one of the element-wise <tt>swap</tt> calls throws 5998an exception.</ins> 5999</blockquote> 6000</li> 6001 6002<li> 6003<ol type="a"> 6004<li> 6005<p> 6006In 23.3.2 [deque], class template deque synopsis change as indicated: 6007</p> 6008<blockquote><pre>void swap(deque<del><T,Alloc></del>&); 6009</pre></blockquote> 6010</li> 6011 6012<li> 6013<p> 6014At the end of 23.3.2.3 [deque.modifiers] add as indicated: 6015</p> 6016 6017<blockquote><pre><ins>void swap(deque& x);</ins> 6018</pre> 6019<blockquote> 6020<p> 6021<ins><i>Effects:</i> Exchanges the contents and swaps the allocators of <tt>*this</tt> 6022with that of <tt>x</tt>.</ins> 6023</p> 6024<p> 6025<ins><i>Complexity:</i> Constant time.</ins> 6026</p> 6027</blockquote> 6028</blockquote> 6029</li> 6030</ol> 6031</li> 6032 6033<li> 6034<ol type="a"> 6035<li> 6036<p> 6037In 23.3.3 [forwardlist], class template <tt>forward_list</tt> synposis change as indicated: 6038</p> 6039 6040<blockquote><pre>void swap(forward_list<del><T,Allocator></del>&); 6041</pre></blockquote> 6042</li> 6043 6044<li> 6045<p> 6046At the end of 23.3.3.4 [forwardlist.modifiers] add as indicated: 6047</p> 6048 6049<blockquote><pre><ins>void swap(forward_list& x);</ins> 6050</pre> 6051<blockquote> 6052<p> 6053<ins><i>Effects:</i> Exchanges the contents and swaps the allocators of <tt>*this</tt> 6054with that of <tt>x</tt>.</ins> 6055</p> 6056<p> 6057<ins><i>Complexity:</i> Constant time.</ins> 6058</p> 6059</blockquote> 6060</blockquote> 6061</li> 6062</ol> 6063</li> 6064 6065<li> 6066<ol type="a"> 6067<li> 6068<p> 6069In 23.3.4 [list], class template <tt>list</tt> synopsis change as indicated: 6070</p> 6071 6072<blockquote><pre>void swap(list<del><T,Allocator></del>&); 6073</pre></blockquote> 6074</li> 6075 6076<li> 6077<p> 6078At the end of 23.3.4.3 [list.modifiers] add as indicated: 6079</p> 6080 6081<blockquote><pre><ins>void swap(list& x);</ins> 6082</pre> 6083 6084<blockquote> 6085<p> 6086<ins><i>Effects:</i> Exchanges the contents and swaps the allocators of <tt>*this</tt> 6087with that of <tt>x</tt>.</ins> 6088</p> 6089 6090<p> 6091<ins><i>Complexity:</i> Constant time.</ins> 6092</p> 6093</blockquote> 6094</blockquote> 6095</li> 6096</ol> 6097</li> 6098 6099<li> 6100<p> 6101At the end of 23.3.5.2.2 [priqueue.members] add a new prototype description: 6102</p> 6103 6104<blockquote><pre><ins>void swap(priority_queue& q);</ins> 6105</pre> 6106<blockquote> 6107<p> 6108<ins><i>Requires:</i> <tt>Compare</tt> shall satisfy the <tt>Swappable</tt> requirements 6109( [swappable]).</ins> 6110</p> 6111 6112<p><i>[ 6113This requirement is added to ensure that even a user defined <tt>swap</tt> 6114which is found by 6115ADL for <tt>Compare</tt> satisfies the <tt>Swappable</tt> requirements 6116]</i></p> 6117 6118 6119<p> 6120<ins><i>Effects:</i> <tt>this->c.swap(q.c); swap(this->comp, q.comp);</tt></ins> 6121</p> 6122<p> 6123<ins><i>Throws:</i> What and if <tt>c.swap(q.c)</tt> and <tt>swap(comp, q.comp)</tt> throws.</ins> 6124</p> 6125</blockquote> 6126</blockquote> 6127<p><i>[ 6128This part is added, because otherwise <tt>priority_queue::swap</tt> would otherwise 6129contradict the general contract of 23.2.1 [container.requirements.general] p. 10 b. 5 6130]</i></p> 6131 6132</li> 6133 6134<li> 6135<ol type="a"> 6136<li> 6137<p> 6138In 23.3.6 [vector], class template <tt>vector</tt> synopsis change as indicated: 6139</p> 6140 6141<blockquote><pre>void swap(vector<del><T,Allocator></del>&); 6142</pre></blockquote> 6143</li> 6144 6145<li> 6146<p> 6147Change 23.3.6.2 [vector.capacity]/8 as indicated: 6148</p> 6149 6150<blockquote><pre>void swap(vector<del><T,Allocator></del>& x); 6151</pre> 6152 6153<blockquote> 6154<i>Effects:</i> Exchanges the contents and <tt>capacity()</tt> <ins>and swaps the 6155allocators</ins> 6156of <tt>*this</tt> with that of <tt>x</tt>. 6157</blockquote> 6158</blockquote> 6159</li> 6160</ol> 6161</li> 6162 6163<li> 6164<p> 6165Insert a new paragraph just before 23.4 [associative]/1: 6166</p> 6167 6168<blockquote> 6169<ins>In addition to being available via inclusion of the <tt><algorithm></tt> header, 6170the <tt>swap</tt> function templates in 25.3.3 [alg.swap] are also available when any of the 6171headers <tt><map></tt> or <tt><set></tt> are included.</ins> 6172</blockquote> 6173</li> 6174 6175<li> 6176<ol type="a"> 6177<li> 6178<p> 6179In 23.4.1 [map], class template <tt>map</tt> synopsis change as indicated: 6180</p> 6181 6182<blockquote><pre>void swap(map<del><Key,T,Compare,Allocator></del>&); 6183</pre></blockquote> 6184</li> 6185 6186<li> 6187<p> 6188At the end of 23.4.1.3 [map.modifiers] add as indicated: 6189</p> 6190 6191<blockquote><pre><ins>void swap(map& x);</ins> 6192</pre> 6193 6194<blockquote> 6195<p> 6196<ins><i>Requires:</i> Compare shall satisfy the <tt>Swappable</tt> requirements 6197( [swappable]).</ins> 6198</p> 6199 6200<p><i>[ 6201This requirement is added to ensure that even a user defined <tt>swap</tt> 6202which is found by ADL for <tt>Compare</tt> satisfies the <tt>Swappable</tt> 6203requirements 6204]</i></p> 6205 6206 6207<p> 6208<ins><i>Effects:</i> Exchanges the contents and swaps the allocators of <tt>*this</tt> 6209with that of <tt>x</tt>, followed by an unqualified <tt>swap</tt> of the comparison objects 6210of <tt>*this</tt> and <tt>x</tt>.</ins> 6211</p> 6212 6213<p> 6214<ins><i>Complexity:</i> Constant time</ins> 6215</p> 6216</blockquote> 6217</blockquote> 6218</li> 6219</ol> 6220</li> 6221 6222<li> 6223<ol type="a"> 6224<li> 6225<p> 6226In 23.4.2 [multimap], class template <tt>multimap</tt> synopsis change as indicated: 6227</p> 6228 6229<blockquote><pre>void swap(multimap<del><Key,T,Compare,Allocator></del>&); 6230</pre></blockquote> 6231</li> 6232 6233<li> 6234<p> 6235At the end of 23.4.2.2 [multimap.modifiers] add as indicated: 6236</p> 6237 6238<blockquote><pre><ins>void swap(multimap& x);</ins> 6239</pre> 6240 6241<blockquote> 6242<p> 6243<ins><i>Requires:</i> Compare shall satisfy the <tt>Swappable</tt> requirements 6244( [swappable]).</ins> 6245</p> 6246<p> 6247<ins><i>Effects:</i> Exchanges the contents and swaps the allocators of <tt>*this</tt> 6248with that of <tt>x</tt>, followed by an unqualified <tt>swap</tt> of the comparison objects 6249of <tt>*this</tt> and <tt>x</tt>.</ins> 6250</p> 6251<p> 6252<ins><i>Complexity:</i> Constant time</ins> 6253</p> 6254</blockquote> 6255</blockquote> 6256</li> 6257</ol> 6258</li> 6259 6260<li> 6261<ol type="a"> 6262<li> 6263<p> 6264In 23.4.3 [set], class template <tt>set</tt> synopsis change as indicated: 6265</p> 6266 6267<blockquote><pre>void swap(set<del><Key,Compare,Allocator></del>&); 6268</pre></blockquote> 6269</li> 6270 6271<li> 6272<p> 6273After section 23.4.3.1 [set.cons] add a new section <ins><tt>set</tt> modifiers 6274 [set.modifiers]</ins> 6275and add the following paragraphs: 6276</p> 6277 6278<blockquote><pre><ins>void swap(set& x);</ins> 6279</pre> 6280 6281<blockquote> 6282<p> 6283<ins><i>Requires:</i> Compare shall satisfy the <tt>Swappable</tt> requirements 6284( [swappable]).</ins> 6285</p> 6286 6287<p> 6288<ins><i>Effects:</i> Exchanges the contents and swaps the allocators of <tt>*this</tt> 6289with that of <tt>x</tt>, followed by an unqualified <tt>swap</tt> of the comparison objects 6290of <tt>*this</tt> and <tt>x</tt>.</ins> 6291</p> 6292 6293<p> 6294<ins>Complexity: Constant time</ins> 6295</p> 6296</blockquote> 6297</blockquote> 6298</li> 6299</ol> 6300</li> 6301 6302<li> 6303<ol type="a"> 6304<li> 6305<p> 6306In 23.4.4 [multiset], class template <tt>multiset</tt> synosis, change as indicated: 6307</p> 6308 6309<blockquote><pre>void swap(multiset<del><Key,Compare,Allocator></del>&); 6310</pre></blockquote> 6311</li> 6312 6313<li> 6314<p> 6315After section 23.4.4.1 [multiset.cons] add a new section <ins><tt>multiset</tt> modifiers 6316 [multiset.modifiers]</ins> and add the following paragraphs: 6317</p> 6318 6319<blockquote><pre><ins>void swap(multiset& x);</ins> 6320</pre> 6321 6322<blockquote> 6323<p> 6324<ins><i>Requires:</i> Compare shall satisfy the <tt>Swappable</tt> requirements 6325( [swappable]).</ins> 6326</p> 6327 6328<p> 6329<ins><i>Effects:</i> Exchanges the contents and swaps the allocators of <tt>*this</tt> 6330with that of <tt>x</tt>, followed by an unqualified <tt>swap</tt> of the comparison objects 6331of <tt>*this</tt> and <tt>x</tt>.</ins> 6332</p> 6333 6334<p> 6335<ins><i>Complexity:</i> Constant time</ins> 6336</p> 6337</blockquote> 6338</blockquote> 6339</li> 6340</ol> 6341</li> 6342 6343<li> 6344<p> 6345Insert a new paragraph just before 23.5 [unord]/1: 6346</p> 6347 6348<blockquote> 6349<ins>In addition to being available via inclusion of the <tt><algorithm></tt> header, 6350the <tt>swap</tt> function templates in 25.3.3 [alg.swap] are also available when any of the 6351headers <tt><unordered_map></tt> or <tt><unordered_set></tt> are included.</ins> 6352</blockquote> 6353 6354</li> 6355 6356<li> 6357<p> 6358After section 23.5.1.2 [unord.map.elem] add a new section <ins>unordered_map 6359modifiers [unord.map.modifiers]</ins> and add the following paragraphs: 6360</p> 6361 6362<blockquote><pre><ins>void swap(unordered_map& x);</ins> 6363</pre> 6364 6365<blockquote> 6366<p> 6367<ins><i>Requires:</i> <tt>Hash</tt> and <tt>Pred</tt> shall satisfy the <tt>Swappable</tt> requirements 6368( [swappable]).</ins> 6369</p> 6370 6371<p><i>[ 6372This requirement is added to ensure that even a user defined <tt>swap</tt> 6373which is found by ADL for <tt>Hash</tt> and <tt>Pred</tt> satisfies the <tt>Swappable</tt> 6374requirements 6375]</i></p> 6376 6377 6378<p> 6379<ins><i>Effects:</i> Exchanges the contents and hash policy and swaps the 6380allocators of <tt>*this</tt> 6381with that of <tt>x</tt>, followed by an unqualified <tt>swap</tt> of the <tt>Pred</tt> objects 6382and an unqualified <tt>swap</tt> of the <tt>Hash</tt> objects of <tt>*this</tt> and <tt>x</tt>.</ins> 6383</p> 6384 6385<p> 6386<ins><i>Complexity:</i> Constant time</ins> 6387</p> 6388</blockquote> 6389</blockquote> 6390</li> 6391 6392<li> 6393<p> 6394After section 23.5.2.1 [unord.multimap.cnstr] add a new section 6395<ins>unordered_multimap 6396modifiers [unord.multimap.modifiers]</ins> and add the following paragraphs: 6397</p> 6398 6399<blockquote><pre><ins>void swap(unordered_multimap& x);</ins> 6400</pre> 6401 6402<blockquote> 6403<p> 6404<ins><i>Requires:</i> <tt>Hash</tt> and <tt>Pred</tt> shall satisfy the <tt>Swappable</tt> requirements 6405( [swappable]).</ins> 6406</p> 6407 6408<p> 6409<ins><i>Effects:</i> Exchanges the contents and hash policy and swaps the 6410allocators of <tt>*this</tt> 6411with that of <tt>x</tt>, followed by an unqualified <tt>swap</tt> of the <tt>Pred</tt> objects 6412and an unqualified <tt>swap</tt> of the <tt>Hash</tt> objects of <tt>*this</tt> and <tt>x</tt></ins> 6413</p> 6414<p> 6415<ins><i>Complexity:</i> Constant time</ins> 6416</p> 6417</blockquote> 6418</blockquote> 6419</li> 6420 6421<li> 6422<p> 6423After section 23.5.3.1 [unord.set.cnstr] add a new section 6424<ins>unordered_set modifiers 6425 [unord.set.modifiers]</ins> and add the following paragraphs: 6426</p> 6427 6428<blockquote><pre><ins>void swap(unordered_set& x);</ins> 6429</pre> 6430 6431<blockquote> 6432<p> 6433<ins><i>Requires:</i> <tt>Hash</tt> and <tt>Pred</tt> shall satisfy the <tt>Swappable</tt> requirements 6434( [swappable]).</ins> 6435</p> 6436 6437<p> 6438<ins><i>Effects:</i> Exchanges the contents and hash policy and swaps the 6439allocators of <tt>*this</tt> 6440with that of <tt>x</tt>, followed by an unqualified <tt>swap</tt> of the <tt>Pred</tt> objects 6441and an unqualified <tt>swap</tt> of the <tt>Hash</tt> objects of <tt>*this</tt> and <tt>x</tt></ins> 6442</p> 6443 6444<p> 6445<ins><i>Complexity:</i> Constant time</ins> 6446</p> 6447</blockquote> 6448</blockquote> 6449</li> 6450 6451<li> 6452<p> 6453After section 23.5.4.1 [unord.multiset.cnstr] add a new section 6454<ins>unordered_multiset 6455modifiers [unord.multiset.modifiers]</ins> and add the following paragraphs: 6456</p> 6457 6458<blockquote><pre><ins>void swap(unordered_multiset& x);</ins> 6459</pre> 6460 6461<blockquote> 6462<p> 6463<ins><i>Requires:</i> <tt>Hash</tt> and <tt>Pred</tt> shall satisfy the <tt>Swappable</tt> requirements 6464( [swappable]).</ins> 6465</p> 6466 6467<p> 6468<ins><i>Effects:</i> Exchanges the contents and hash policy and swaps the 6469allocators of <tt>*this</tt> 6470with that of <tt>x</tt>, followed by an unqualified <tt>swap</tt> of the <tt>Pred</tt> objects 6471and an unqualified <tt>swap</tt> of the <tt>Hash</tt> objects of <tt>*this</tt> and <tt>x</tt></ins> 6472</p> 6473<p> 6474<ins><i>Complexity:</i> Constant time</ins> 6475</p> 6476</blockquote> 6477</blockquote> 6478</li> 6479 6480</ol> 6481 6482</blockquote> 6483 6484<p><i>[ 64852009-10-30 Pablo and Daniel updated wording. 6486]</i></p> 6487 6488 6489 6490 6491<p><b>Proposed resolution:</b></p> 6492 6493<p><i>[ 6494This resolution is based on the September 2009 WP, 6495<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2960.pdf">N2960</a>, 6496except that it 6497assumes that 6498<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2982.pdf">N2982</a> 6499and issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#883">883</a> and <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1232">1232</a> have already been applied. Note in 6500particular that Table 91 in 6501<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2960.pdf">N2960</a> 6502is refered to as Table 90 because 6503<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2982.pdf">N2982</a> 6504removed the old Table 90. This resolution also addresses issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#431">431</a>. 6505]</i></p> 6506 6507<p> 6508In 23.2.1 [container.requirements.general], replace the a.swap(b) row in table 90, 6509"container requirements" (was table 91 before the application of <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2982.pdf">N2982</a> to the 6510WP): 6511</p> 6512<blockquote> 6513<table border="1"> 6514 <tbody><tr> 6515 <td><code>a.swap(b)</code></td> 6516 <td><code>void</code></td> 6517 <td> </td> 6518 <td><code><del>swap(a,b)</del><ins>Exchange the contents of <tt>a</tt> and <tt>b</tt>.</ins></code></td> 6519 <td>(Note A)</td> 6520 </tr> 6521 <tr> 6522 <td><ins><code>swap(a,b)</code></ins></td> 6523 <td><ins><code>void</code></ins></td> 6524 <td><code> </code></td> 6525 <td><ins><code>a.swap(b)</code></ins></td> 6526 <td><ins>(Note A)</ins></td> 6527 </tr> 6528</tbody></table> 6529</blockquote> 6530<p> 6531Modify the notes immediately following Table 90 in 653223.2.1 [container.requirements.general] as follows (The wording below is after the 6533application of <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2982.pdf">N2982</a> to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2960.pdf">N2960</a>. The editor might also want to combine Notes 6534A and B into one.): 6535</p> 6536<blockquote><p> 6537Notes: the algorithms<del> swap(),</del> equal() and lexicographical_compare() 6538are defined in Clause 25. Those entries marked "(Note A)" or "(Note B)" 6539<del>should</del> have <ins>linear complexity for array and</ins> constant 6540complexity <ins>for all other standard containers</ins>. 6541</p></blockquote> 6542<p> 6543In 23.2.1 [container.requirements.general], after paragraph 9, add: 6544</p> 6545<blockquote><p><ins> 6546The expression <code>a.swap(b)</code>, for containers <code>a</code> 6547and <code>b</code> of a standard container type other than <code>array</code>, 6548exchanges the values of <code>a</code> and <code>b</code> without invoking any 6549move, copy, or swap operations on the individual container elements. 6550Any <code>Compare</code>, <code>Pred</code>, or <code>Hash</code> function 6551objects belonging to <code>a</code> and <code>b</code> shall satisfy 6552the <code>Swappable</code> requirements and are exchanged by unqualified calls 6553to non-member <code>swap</code>. If 6554<code>allocator_traits<allocator_type>::propagate_on_container_swap::value 6555== true</code>, then the allocators of <code>a</code> and <code>b</code> are 6556also exchanged using an unqualified call to non-member <code>swap</code>. 6557Otherwise, the behavior is undefined unless <code>a.get_allocator() == 6558b.get_allocator()</code>. Each iterator refering to an element in one 6559container before the swap shall refer to the same element in the other 6560container after the swap. It is unspecified whether an iterator with 6561value <code>a.end()</code> before the swap will have 6562value <code>b.end()</code> after the swap. In addition to being available via 6563inclusion of the <code><utility></code> header, the <code>swap</code> 6564function template in 25.3.3 [alg.swap] is also available within the definition of 6565every standard container's <code>swap</code> function. 6566</ins></p></blockquote> 6567<p><i>[ 6568Note to the editor: Paragraph 2 starts with a sentence fragment, 6569clearly from an editing or source-control error. 6570]</i></p> 6571 6572<p> 6573Modify 23.2.4.1 [associative.reqmts.except] as follows: 6574</p> 6575<blockquote> 6576<p> 6577<b>23.2.4.1 Exception safety guarantees 23.2.4.1 [associative.reqmts.except]</b> 6578</p> 6579<p> 6580For associative containers, no <code>clear()</code> function throws an 6581exception. <code>erase(k)</code> does not throw an exception unless that 6582exception is thrown by the 6583container's <code><del>Pred</del><ins>Compare</ins></code> object (if any). 6584</p> 6585<p> 6586For associative containers, if an exception is thrown by any operation from 6587within an <code>insert()</code> function inserting a single element, 6588the <code>insert()</code> function has no effect. 6589</p> 6590<p> 6591For associative containers, no <code>swap</code> function throws an exception 6592unless that exception is thrown by the <del>copy constructor 6593or copy assignment operator</del><ins>swap</ins> of the 6594container's <code><del>Pred</del><ins>Compare</ins></code> object (if any). 6595</p></blockquote> 6596<p> 6597Modify 23.2.5.1 [unord.req.except], paragraph 3 as follows: 6598</p> 6599<blockquote><p> 6600For unordered associative containers, no <code>swap</code> function throws an 6601exception unless that exception is thrown by the <del>copy constructor or copy 6602assignment operator</del><ins>swap</ins> of the container's <code>Hash</code> 6603or <code>Pred</code> object (if any). 6604</p></blockquote> 6605<p> 6606Modify section 23.3.1.2 [array.special]: 6607</p> 6608<blockquote> 6609<p> 6610<b>array specialized algorithms 23.3.1.2 [array.special]</b> 6611</p> 6612<p> 6613<code>template <class T, size_t N> void swap(array<T,N>& x,array<T,N>& y);</code> 6614</p> 6615<blockquote> 6616<p> 6617<i>Effects:</i> <code><del>swap_ranges(x.begin(), x.end(), y.begin() );</del><ins>x.swap(y);</ins></code> 6618</p> 6619</blockquote> 6620</blockquote> 6621<p> 6622Add a new section after 23.3.1.5 [array.fill] (Note to the editor: array::fill make use 6623of a concept requirement that must be removed or changed to text.): 6624</p> 6625<blockquote> 6626<p> 6627<ins><b>array::swap [array.swap]</b></ins> 6628</p> 6629<p> 6630<ins><code>void swap(array& y);</code></ins> 6631</p> 6632<blockquote> 6633<p><ins> 6634<i>Effects:</i> <code>swap_ranges(this->begin(), this->end(), y.begin() );</code> 6635</ins></p> 6636<p><ins> 6637<i>Throws:</i> Nothing unless one of the element-wise swap calls throws an 6638exception. 6639</ins></p> 6640<p><ins> 6641[<i>Note</i>: Unlike other containers' <code>swap</code> functions, 6642<code>array::swap</code> takes linear, not constant, time, may exit via an 6643exception, and does not cause iterators to become associated with the other 6644container. — <i>end note</i>] 6645</ins></p> 6646</blockquote> 6647</blockquote> 6648 6649<p> 6650Insert a new paragraph just after 23.3.5 [container.adaptors]/1: 6651</p> 6652<blockquote><p><ins> 6653For container adaptors, no <code>swap</code> function throws an exception 6654unless that exception is thrown by the swap of the 6655adaptor's <code>Container</code> or <code>Compare</code> object (if any). 6656</ins></p></blockquote> 6657 6658 6659 6660 6661 6662 6663 6664 6665 6666 6667 6668 6669<hr> 6670<h3><a name="780"></a>780. <tt>std::merge()</tt> specification incorrect/insufficient</h3> 6671<p><b>Section:</b> 25.4.4 [alg.merge] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Review">Review</a> 6672 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2008-01-25 <b>Last modified:</b> 2009-10-22</p> 6673<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Review">Review</a> status.</p> 6674<p><b>Discussion:</b></p> 6675<p> 6676Though issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#283">283</a> has fixed many open issues, it seems that some are still open: 6677</p> 6678 6679<p> 6680Both 25.3.4 [lib.alg.merge] in 14882:2003 and 25.4.4 [alg.merge] in N2461 6681have no Requires element and the Effects element contains some requirements, 6682which is probably editorial. Worse is that: 6683</p> 6684 6685<ul> 6686<li> 6687no assignment requirements are specified (neither implicit nor explicit). 6688</li> 6689 6690<li> 6691the effects clause just speaks of "merges", which is badly worded 6692near to a circular definition. 6693</li> 6694 6695<li> 6696p. 2 mentions a range <tt>[first, last)</tt>, which is not defined by the 6697function arguments or otherwise. 6698</li> 6699 6700<li> 6701p. 2 says "according to the ordering defined by comp" which is both 6702incomplete (because 6703this excludes the first variant with <) and redundant (because the 6704following subordinate 6705clause mentions comp again) 6706</li> 6707</ul> 6708 6709<p><i>[ 6710Post Summit Alisdair adds: 6711]</i></p> 6712 6713 6714<blockquote> 6715<p> 6716Suggest: 6717</p> 6718<blockquote> 6719(where <tt>last</tt> is equal to <tt>next(result, distance(first1, last1) + 6720distance(first2, last2))</tt>, such that resulting range will be sorted in 6721non-decreasing order; that is, for every iterator <tt>i</tt> in <tt>[result,last)</tt> other 6722than <tt>result</tt>, the condition <tt>*i < *prev(i)</tt> or, respectively, <tt>comp(*i, 6723*prev(i))</tt> will be <tt>false</tt>. 6724</blockquote> 6725 6726<p> 6727Note that this might still not be technically accurate in the case of 6728<tt>InputIterators</tt>, depending on other resolutions working their way through the 6729system (<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1011">1011</a>). 6730</p> 6731</blockquote> 6732 6733<p><i>[ 6734Post Summit Daniel adds: 6735]</i></p> 6736 6737 6738<blockquote> 6739If we want to use <tt>prev</tt> and <tt>next</tt> here (Note: <tt>merge</tt> 6740is sufficiently satisfied with <tt>InputIterator</tt>) we should instead *add* more to 674125 [algorithms]/6, but I can currently not propose any good wording for this. 6742</blockquote> 6743 6744<p><i>[ 6745Batavia (2009-05): 6746]</i></p> 6747 6748<blockquote> 6749<p> 6750Pete points out the existing wording in [algorithms]/4 6751that permits the use of + in algorithm specifications. 6752</p> 6753<p> 6754Alisdair points out that that wording may not apply to input iterators. 6755</p> 6756<p> 6757Move to Review. 6758</p> 6759</blockquote> 6760 6761<p><i>[ 67622009-07 Frankfurt: 6763]</i></p> 6764 6765 6766<blockquote> 6767Move to Ready. 6768</blockquote> 6769 6770<p><i>[ 67712009-08-23 Daniel reopens: 6772]</i></p> 6773 6774 6775<blockquote> 6776<p> 6777The proposed wording must be rephrased, because the part 6778</p> 6779 6780<blockquote> 6781for every iterator <tt>i</tt> in <tt>[result,last)</tt> other than <tt>result</tt>, the condition 6782<tt>*i < *(i - 1)</tt> or, respectively, <tt>comp(*i, *(i - 1))</tt> will be <tt>false</tt>" 6783</blockquote> 6784 6785<p> 6786isn't meaningful, because the range <tt>[result,last)</tt> is that of a pure 6787<tt>OutputIterator</tt>, which is not <em>readable</em> in general. 6788</p> 6789 6790<p><i>[Howard: Proposed wording updated by Daniel, status moved from Ready to Review.]</i></p> 6791 6792</blockquote> 6793 6794<p><i>[ 67952009-10 Santa Cruz: 6796]</i></p> 6797 6798 6799<blockquote> 6800<p> 6801Matt has some different words to propose. Those words have been moved into 6802the proposed wording section, and the original proposed wording now appears 6803here: 6804</p> 6805<blockquote> 6806<p> 6807In 25.4.4 [alg.merge] replace p.1+ 2: 6808</p> 6809 6810<blockquote> 6811<p> 6812<i>Effects:</i> <del>Merges</del><ins>Copies all the elements of the</ins> 6813two sorted ranges 6814<tt>[first1,last1)</tt> and <tt>[first2,last2)</tt> into the range <tt>[result,result + 6815(last1 - first1) + (last2 - first2))</tt> 6816<ins>, such that resulting range will be sorted in non-decreasing 6817order; that is for every 6818pair of iterators <tt>i</tt> and <tt>j</tt> of either input ranges, where <tt>*i</tt> was copied 6819to the output range 6820before <tt>*j</tt> was copied to the output range, the condition <tt>*j < *i</tt> or, 6821respectively, <tt>comp(*j, *i)</tt> 6822will be <tt>false</tt>.</ins> 6823</p> 6824 6825<p> 6826<ins><i>Requires:</i></ins>The resulting range shall not overlap with either 6827of the original ranges. 6828<del>The list will be sorted in non-decreasing order according to the 6829ordering defined by 6830<tt>comp</tt>; that is, for every iterator <tt>i</tt> in <tt>[first,last)</tt> other than <tt>first</tt>, 6831the condition <tt>*i < *(i - 1)</tt> or 6832<tt>comp(*i, *(i - 1))</tt> will be <tt>false</tt>.</del> 6833</p> 6834</blockquote> 6835</blockquote> 6836</blockquote> 6837 6838 6839 6840<p><b>Proposed resolution:</b></p> 6841<p><del> 6842<i>Effects:</i> Merges two sorted ranges <tt>[first1,last1)</tt> and 6843<tt>[first2,last2)</tt> into the range <tt>[result, result + (last1 - 6844first1) + (last2 - first2))</tt>. 6845</del></p> 6846<p><ins> 6847<i>Effects:</i> Copies all the elements of the two sorted ranges 6848<tt>[first1,last1)</tt> and <tt>[first2,last2)</tt> into the range 6849<tt>[result, result_last)</tt>, where <tt>result_last</tt> is <tt>result 6850+ (last1 - first1) + (last2 - first2)</tt>, such that the resulting 6851range satisfies <tt>is_sorted(result, result_last)</tt> or 6852<tt>is_sorted(result, result_last, comp)</tt>, respectively. 6853</ins></p> 6854 6855<p> 6856<ins><i>Requires:</i></ins> The resulting range shall not overlap with 6857either of the original ranges. <del>The list will be sorted in 6858non-decreasing order according to the ordering defined by <tt>comp</tt>; 6859that is, for every iterator <tt>i</tt> in <tt>[first,last)</tt> other 6860than <tt>first</tt>, the condition <tt>*i < *(i - 1)</tt> or 6861<tt>comp(*i, *(i - 1))</tt> will be <tt>false</tt>.</del> 6862</p> 6863 6864 6865 6866 6867 6868 6869<hr> 6870<h3><a name="801"></a>801. <tt>tuple</tt> and <tt>pair</tt> trivial members</h3> 6871<p><b>Section:</b> 20.5 [tuple] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 6872 <b>Submitter:</b> Lawrence Crowl <b>Opened:</b> 2008-02-18 <b>Last modified:</b> 2009-10-23</p> 6873<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#tuple">issues</a> in [tuple].</p> 6874<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 6875<p><b>Discussion:</b></p> 6876<p> 6877Classes with trivial special member functions are inherently more 6878efficient than classes without such functions. This efficiency is 6879particularly pronounced on modern ABIs that can pass small classes 6880in registers. Examples include value classes such as complex numbers 6881and floating-point intervals. Perhaps more important, though, are 6882classes that are simple collections, like <tt>pair</tt> and <tt>tuple</tt>. When the 6883parameter types of these classes are trivial, the <tt>pair</tt>s and <tt>tuple</tt>s 6884themselves can be trivial, leading to substantial performance wins. 6885</p> 6886<p> 6887The current working draft make specification of trivial functions 6888(where possible) much easer through <tt>default</tt>ed and <tt>delete</tt>d functions. 6889As long as the semantics of defaulted and deleted functions match 6890the intended semantics, specification of defaulted and deleted 6891functions will yield more efficient programs. 6892</p> 6893<p> 6894There are at least two cases where specification of an explicitly 6895defaulted function may be desirable. 6896</p> 6897<p> 6898First, the <tt>std::pair</tt> template has a non-trivial default constructor, 6899which prevents static initialization of the pair even when the 6900types are statically initializable. Changing the definition to 6901</p> 6902 6903<blockquote><pre>pair() = default; 6904</pre></blockquote> 6905 6906<p> 6907would enable such initialization. Unfortunately, the change is 6908not semantically neutral in that the current definition effectively 6909forces value initialization whereas the change would not value 6910initialize in some contexts. 6911</p> 6912 6913<p> 6914** Does the committee confirm that forced value initialization 6915was the intent? If not, does the committee wish to change the 6916behavior of <tt>std::pair</tt> in C++0x? 6917</p> 6918<p> 6919Second, the same default constructor issue applies to <tt>std::tuple</tt>. 6920Furthermore, the <tt>tuple</tt> copy constructor is current non-trivial, 6921which effectively prevents passing it in registers. To enable 6922passing <tt>tuples</tt> in registers, the copy constructor should be 6923make explicitly <tt>default</tt>ed. The new declarations are: 6924</p> 6925 6926<blockquote><pre>tuple() = default; 6927tuple(const tuple&) = default; 6928</pre></blockquote> 6929 6930<p> 6931This changes is not implementation neutral. In particular, it 6932prevents implementations based on pointers to the parameter 6933types. It does however, permit implementations using the 6934parameter types as bases. 6935</p> 6936<p> 6937** How does the committee wish to trade implementation 6938efficiency versus implementation flexibility? 6939</p> 6940 6941<p><i>[ 6942Bellevue: 6943]</i></p> 6944 6945 6946<blockquote> 6947<p> 6948General agreement; the first half of the issue is NAD. 6949</p> 6950<p> 6951Before voting on the second half, it was agreed that a "Strongly Favor" 6952vote meant support for trivial tuples (assuming usual requirements met), 6953even at the expense of other desired qualities. A "Weakly Favor" vote 6954meant support only if not at the expense of other desired qualities. 6955</p> 6956<p> 6957Concensus: Go forward, but not at expense of other desired qualities. 6958</p> 6959<p> 6960It was agreed to Alisdair should fold this work in with his other 6961pair/tuple action items, above, and that issue 801 should be "open", but 6962tabled until Alisdair's proposals are disposed of. 6963</p> 6964</blockquote> 6965 6966<p><i>[ 69672009-05-27 Daniel adds: 6968]</i></p> 6969 6970 6971<blockquote> 6972This is partly solved by <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1117">1117</a>. 6973</blockquote> 6974 6975<p><i>[ 69762009-07 Frankfurt: 6977]</i></p> 6978 6979 6980<blockquote> 6981Wait for dust to settle from fixing exception safety problem 6982with rvalue refs. 6983</blockquote> 6984 6985<p><i>[ 69862009-07-20 Alisdair adds: 6987]</i></p> 6988 6989 6990<blockquote> 6991<p> 6992Basically, this issue is what should we do with the default constructor 6993for pairs and tuples of trivial types. The motivation of the issue was 6994to force static initialization rather than dynamic initialization, and 6995was rejected in the case of pair as it would change the meaning of 6996existing programs. The advice was "do the best we can" for tuple 6997without changing existing meaning. 6998</p> 6999 7000<p> 7001Frankfurt seems to simply wait and see the resolution on no-throw move 7002constructors, which (I believe) is only tangentially related to this 7003issue, but as good as any to defer until Santa Cruz. 7004</p> 7005 7006<p> 7007Looking again now, I think constant (static) initialization for pair can 7008be salvaged by making the default construct constexpr. I have a 7009clarification from Core that this is intended to work, even if the 7010constructor is not trivial/constexpr, so long as no temporaries are 7011implied in the process (even if elided). 7012</p> 7013</blockquote> 7014 7015<p><i>[ 70162009-10 Santa Cruz: 7017]</i></p> 7018 7019 7020<blockquote> 7021Leave as open. Alisdair to provide wording. 7022</blockquote> 7023 7024 7025 7026<p><b>Proposed resolution:</b></p> 7027<p> 7028</p> 7029 7030 7031 7032 7033 7034<hr> 7035<h3><a name="811"></a>811. <tt>pair</tt> of pointers no longer works with literal 0</h3> 7036<p><b>Section:</b> 20.3.4 [pairs] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 7037 <b>Submitter:</b> Doug Gregor <b>Opened:</b> 2008-03-14 <b>Last modified:</b> 2009-10-23</p> 7038<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#pairs">active issues</a> in [pairs].</p> 7039<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#pairs">issues</a> in [pairs].</p> 7040<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 7041<p><b>Discussion:</b></p> 7042<blockquote><pre>#include <utility> 7043 7044int main() 7045{ 7046 std::pair<char *, char *> p (0,0); 7047} 7048</pre></blockquote> 7049 7050<p> 7051I just got a bug report about that, because it's valid C++03, but not 7052C++0x. The important realization, for me, is that the emplace 7053proposal---which made <tt>push_back</tt> variadic, causing the <tt>push_back(0)</tt> 7054issue---didn't cause this break in backward compatibility. The break 7055actually happened when we added this pair constructor as part of adding 7056rvalue references into the language, long before variadic templates or 7057emplace came along: 7058</p> 7059 7060<blockquote><pre>template<class U, class V> pair(U&& x, V&& y); 7061</pre></blockquote> 7062 7063<p> 7064Now, concepts will address this issue by constraining that <tt>pair</tt> 7065constructor to only <tt>U</tt>'s and <tt>V</tt>'s that can properly construct "first" and 7066"second", e.g. (from 7067<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2322.pdf">N2322</a>): 7068</p> 7069 7070<blockquote><pre>template<class U , class V > 7071requires Constructible<T1, U&&> && Constructible<T2, V&&> 7072pair(U&& x , V&& y ); 7073</pre></blockquote> 7074 7075<p><i>[ 7076San Francisco: 7077]</i></p> 7078 7079 7080<blockquote> 7081<p> 7082Suggested to resolve using pass-by-value for that case. 7083</p> 7084<p> 7085Side question: Should pair interoperate with tuples? Can construct a 7086tuple of a pair, but not a pair from a two-element tuple. 7087</p> 7088<p> 7089Related to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#885">885</a>. 7090</p> 7091</blockquote> 7092 7093<p><i>[ 70942009-07-28 Reopened by Alisdair. No longer solved by concepts. 7095]</i></p> 7096 7097 7098<p><i>[ 70992009-10 Santa Cruz: 7100]</i></p> 7101 7102 7103<blockquote> 7104Leave as open. Howard to provide wording. 7105</blockquote> 7106 7107 7108 7109<p><b>Proposed resolution:</b></p> 7110<p> 7111</p> 7112 7113 7114<p><b>Rationale:</b></p> 7115<p><i>[ 7116San Francisco: 7117]</i></p> 7118 7119 7120<blockquote> 7121Solved by 7122<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2770.pdf">N2770</a>. 7123</blockquote> 7124 7125 7126 7127 7128 7129 7130 7131<hr> 7132<h3><a name="815"></a>815. <tt>std::function</tt> and <tt>reference_closure</tt> do not use perfect forwarding</h3> 7133<p><b>Section:</b> 20.7.15.2.4 [func.wrap.func.inv] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 7134 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2008-03-16 <b>Last modified:</b> 2009-10-23</p> 7135<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 7136<p><b>Discussion:</b></p> 7137<p> 7138<tt>std::function</tt> and <tt>reference_closure</tt> should use "perfect forwarding" as 7139described in the rvalue core proposal. 7140</p> 7141 7142<p><i>[ 7143Sophia Antipolis: 7144]</i></p> 7145 7146 7147<blockquote> 7148According to Doug Gregor, as far as <tt>std::function</tt> is concerned, perfect 7149forwarding can not be obtained because of type erasure. Not everyone 7150agreed with this diagnosis of forwarding. 7151</blockquote> 7152 7153<p><i>[ 71542009-05-01 Howard adds: 7155]</i></p> 7156 7157 7158<blockquote> 7159<p> 7160Sebastian Gesemann brought to my attention that the <tt>CopyConstructible</tt> 7161requirement on <tt>function</tt>'s <tt>ArgTypes...</tt> is an unnecessary 7162restriction. 7163</p> 7164 7165<blockquote><pre>template<Returnable R, <b>CopyConstructible</b>... ArgTypes> 7166class function<R(ArgTypes...)> 7167... 7168</pre></blockquote> 7169 7170<p> 7171On further investigation, this complaint seemed to be the same 7172issue as this one. I believe the reason <tt>CopyConstructible</tt> was put 7173on <tt>ArgTypes</tt> in the first place was because of the nature of the 7174<i>invoke</i> member: 7175</p> 7176 7177<blockquote><pre>template<class R, class ...ArgTypes> 7178R 7179function<R(ArgTypes...)>::operator()(ArgTypes... arg) const 7180{ 7181 if (f_ == 0) 7182 throw bad_function_call(); 7183 return (*f_)(arg...); 7184} 7185</pre></blockquote> 7186 7187<p> 7188However now with rvalue-refs, "by value" no longer implies <tt>CopyConstructible</tt> 7189(as Sebastian correctly points out). If rvalue arguments are supplied, <tt>MoveConstructible</tt> 7190is sufficient. Furthermore, the constraint need not be applied in <tt>function</tt> 7191if I understand correctly. Rather the client must apply the proper constraints 7192at the call site. Therefore, at the very least, I recommend that <tt>CopyConstructible</tt> 7193be removed from the template class <tt>function</tt>. 7194</p> 7195 7196<p> 7197Furthermore we need to mandate that the <i>invoker</i> is coded as: 7198</p> 7199 7200<blockquote><pre>template<class R, class ...ArgTypes> 7201R 7202function<R(ArgTypes...)>::operator()(ArgTypes... arg) const 7203{ 7204 if (f_ == 0) 7205 throw bad_function_call(); 7206 return (*f_)(<b>std::forward<ArgTypes>(</b>arg<b>)</b>...); 7207} 7208</pre></blockquote> 7209 7210<p> 7211Note that <tt>ArgTypes&&</tt> (the "perfect forwarding signature") is not 7212appropriate here as this is not a deduced context for <tt>ArgTypes</tt>. Instead 7213the client's arguments must implicitly convert to the non-deduced <tt>ArgType</tt> 7214type. Catching these arguments by value makes sense to enable decay. 7215</p> 7216 7217<p> 7218Next <tt>forward</tt> is used to move the <tt>ArgTypes</tt> as efficiently as 7219possible, and also with minimum requirements (not <tt>CopyConstructible</tt>) 7220to the type-erased functor. For object types, this will be a <tt>move</tt>. For 7221reference type <tt>ArgTypes</tt>, this will be a copy. The end result <em>must</em> be 7222that the following is a valid program: 7223</p> 7224 7225<blockquote><pre>#include <functional> 7226#include <memory> 7227#include <cassert> 7228 7229std::unique_ptr<int> 7230f(std::unique_ptr<int> p, int& i) 7231{ 7232 ++i; 7233 return std::move(p); 7234} 7235 7236int main() 7237{ 7238 int i = 2; 7239 std::function<std::unique_ptr<int>(std::unique_ptr<int>, 7240 int&> g(f); 7241 std::unique_ptr<int> p = g(std::unique_ptr<int>(new int(1)), i); 7242 assert(*p == 1); 7243 assert(i == 3); 7244} 7245</pre></blockquote> 7246 7247<p><i>[ 7248Tested in pre-concepts rvalue-ref-enabled compiler. 7249]</i></p> 7250 7251 7252<p> 7253In the example above, the first <tt>ArgType</tt> is <tt>unique_ptr<int></tt> 7254and the second <tt>ArgType</tt> is <tt>int&</tt>. Both <em>must</em> work! 7255</p> 7256 7257</blockquote> 7258 7259<p><i>[ 72602009-05-27 Daniel adds: 7261]</i></p> 7262 7263 7264<blockquote> 7265<p> 7266in the 2009-05-01 comment of above mentioned issue Howard 7267</p> 7268 7269<ol type="a"> 7270<li> 7271Recommends to replace the <tt>CopyConstructible</tt> requirement by a 7272<tt>MoveConstructible</tt> requirement 7273</li> 7274<li> 7275Says: "Furthermore, the constraint need not be applied in <tt>function</tt> if I 7276understand correctly. Rather the client must apply the proper constraints 7277at the call site" 7278</li> 7279</ol> 7280<p> 7281I'm fine with (a), but I think comment (b) is incorrect, at least in the 7282sense I read these sentences. Let's look at Howard's example code: 7283</p> 7284 7285<blockquote><pre>function<R(ArgTypes...)>::operator()(ArgTypes... arg) const 7286{ 7287 if (f_ == 0) 7288 throw bad_function_call(); 7289 return (*f_)(std::forward<ArgTypes>(arg)...); 7290} 7291</pre></blockquote> 7292 7293<p> 7294In the constrained scope of this <tt>operator()</tt> overload the expression 7295"<tt>(*f_)(std::forward<ArgTypes>(arg)...)</tt>" must be valid. How can it 7296do so, if <tt>ArgTypes</tt> aren't at least <tt>MoveConstructible</tt>? 7297</p> 7298</blockquote> 7299 7300<p><i>[ 73012009-07 Frankfurt: 7302]</i></p> 7303 7304 7305<blockquote> 7306Leave this open and wait until concepts are removed from the Working 7307Draft so that we know how to write the proposed resolution in terms of 7308diffs to otherwise stable text. 7309</blockquote> 7310 7311<p><i>[ 73122009-10 Santa Cruz: 7313]</i></p> 7314 7315 7316<blockquote> 7317Leave as open. Howard to provide wording. Howard welcomes any help. 7318</blockquote> 7319 7320 7321 7322<p><b>Proposed resolution:</b></p> 7323<p> 7324</p> 7325 7326 7327 7328 7329 7330<hr> 7331<h3><a name="816"></a>816. Should <tt>bind()</tt>'s returned functor have a nofail copy ctor when <tt>bind()</tt> is nofail?</h3> 7332<p><b>Section:</b> 20.7.11.1.3 [func.bind.bind] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 7333 <b>Submitter:</b> Stephan T. Lavavej <b>Opened:</b> 2008-02-08 <b>Last modified:</b> 2009-11-07</p> 7334<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#func.bind.bind">active issues</a> in [func.bind.bind].</p> 7335<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#func.bind.bind">issues</a> in [func.bind.bind].</p> 7336<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 7337<p><b>Discussion:</b></p> 7338<p> 7339Library Issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#527">527</a> notes that <tt>bind(f, t1, ..., tN)</tt> 7340should be nofail when <tt>f, t1, ..., tN</tt> have nofail copy ctors. 7341</p> 7342<p> 7343However, no guarantees are provided for the copy ctor of the functor 7344returned by <tt>bind()</tt>. (It's guaranteed to have a copy ctor, which can 7345throw implementation-defined exceptions: <tt>bind()</tt> returns a forwarding 7346call wrapper, TR1 3.6.3/2. A forwarding call wrapper is a call wrapper, 7347TR1 3.3/4. Every call wrapper shall be CopyConstructible, TR1 3.3/4. 7348Everything without an exception-specification may throw 7349implementation-defined exceptions unless otherwise specified, C++03 735017.4.4.8/3.) 7351</p> 7352<p> 7353Should the nofail guarantee requested by Library Issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#527">527</a> be extended 7354to cover both calling <tt>bind()</tt> and copying the returned functor? 7355</p> 7356 7357<p><i>[ 7358Howard adds: 7359]</i></p> 7360 7361 7362<blockquote> 7363<tt>tuple</tt> construction should probably have a similar guarantee. 7364</blockquote> 7365 7366<p><i>[ 7367San Francisco: 7368]</i></p> 7369 7370 7371<blockquote> 7372Howard to provide wording. 7373</blockquote> 7374 7375<p><i>[ 7376Post Summit, Anthony provided wording. 7377]</i></p> 7378 7379 7380<p><i>[ 7381Batavia (2009-05): 7382]</i></p> 7383 7384<blockquote> 7385Part of all of this issue appears to be rendered moot 7386by the proposed resolution to issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#817">817</a> (q.v.). 7387We recommend the issues be considered simultaneously 7388(or possibly even merged) 7389to ensure there is no overlap. 7390Move to Open, and likewise for issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#817">817</a>. 7391</blockquote> 7392 7393<p><i>[ 73942009-07 Frankfurt: 7395]</i></p> 7396 7397 7398<blockquote> 7399Related to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#817">817</a> (see below). Leave Open. 7400</blockquote> 7401 7402<p><i>[ 74032009-10 Santa Cruz: 7404]</i></p> 7405 7406 7407<blockquote> 7408Move to Ready. Decoupling from issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#817">817</a>. 7409</blockquote> 7410 7411 7412 7413<p><b>Proposed resolution:</b></p> 7414<p> 7415Add a new sentence to the end of paragraphs 2 and 4 of 20.7.11.1.3 [func.bind.bind]: 7416</p> 7417 7418<blockquote> 7419<p> 7420-2- <i>Returns:</i> A forwarding call wrapper <tt>g</tt> with a weak result type (20.6.2). The effect of <tt>g(u1, u2, 7421..., uM)</tt> shall be <tt><i>INVOKE</i>(f, v1, v2, ..., vN, Callable<F cv,V1, V2, ..., VN>::result_type)</tt>, where <i>cv</i> 7422represents the <i>cv</i>-qualifiers of <tt>g</tt> and the values and types of the bound arguments 7423<tt>v1, v2, ..., vN</tt> are determined as specified below. 7424<ins>The copy constructor and move constructor of the forwarding call wrapper shall throw an 7425exception if and only if the corresponding constructor of <tt>F</tt> or any of the types 7426in <tt>BoundArgs...</tt> throw an exception.</ins> 7427</p> 7428<p>...</p> 7429<p> 7430-5- <i>Returns:</i> A forwarding call wrapper <tt>g</tt> with a nested type <tt>result_type</tt> defined as a synonym 7431for <tt>R</tt>. The effect of <tt>g(u1, u2, ..., uM)</tt> shall be <tt><i>INVOKE</i>(f, v1, v2, ..., vN, R)</tt>, where the 7432values and types of the bound arguments <tt>v1, v2, ..., vN</tt> are determined as specified below. 7433<ins>The copy constructor and move constructor of the forwarding call wrapper shall throw an 7434exception if and only if the corresponding constructor of <tt>F</tt> or any of the types 7435in <tt>BoundArgs...</tt> throw an exception.</ins> 7436</p> 7437 7438</blockquote> 7439 7440 7441 7442 7443 7444<hr> 7445<h3><a name="817"></a>817. <tt>bind</tt> needs to be moved</h3> 7446<p><b>Section:</b> 20.7.11.1.3 [func.bind.bind] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 7447 <b>Submitter:</b> Howard Hinnant <b>Opened:</b> 2008-03-17 <b>Last modified:</b> 2009-11-08</p> 7448<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#func.bind.bind">active issues</a> in [func.bind.bind].</p> 7449<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#func.bind.bind">issues</a> in [func.bind.bind].</p> 7450<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 7451<p><b>Discussion:</b></p> 7452<p><b>Addresses US 72, JP 38 and DE 21</b></p> 7453 7454<p> 7455The functor returned by <tt>bind()</tt> should have a move constructor that 7456requires only move construction of its contained functor and bound arguments. 7457That way move-only functors can be passed to objects such as <tt>thread</tt>. 7458</p> 7459<p> 7460This issue is related to issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#816">816</a>. 7461</p> 7462 7463<p> 7464US 72: 7465</p> 7466 7467<blockquote> 7468<tt>bind</tt> should support move-only functors and bound arguments. 7469</blockquote> 7470 7471<p> 7472JP 38: 7473</p> 7474 7475<blockquote> 7476<p> 7477add the move requirement for bind's return type. 7478</p> 7479<p> 7480For example, assume following <tt>th1</tt> and <tt>th2</tt>, 7481</p> 7482 7483<blockquote><pre>void f(vector<int> v) { } 7484 7485vector<int> v{ ... }; 7486thread th1([v]{ f(v); }); 7487thread th2(bind(f, v)); 7488</pre></blockquote> 7489 7490<p> 7491When function object are set to thread, <tt>v</tt> is moved to <tt>th1</tt>'s lambda 7492expression in a Move Constructor of lambda expression because <tt>th1</tt>'s lambda 7493expression has a Move Constructor. But <tt>bind</tt> of <tt>th2</tt>'s 7494return type doesn't have the requirement of Move, so it may not 7495moved but copied. 7496</p> 7497<p> 7498Add the requirement of move to get rid of this useless copy. 7499</p> 7500<p> 7501And also, add the <tt>MoveConstructible</tt> as well as <tt>CopyConstructible</tt>. 7502</p> 7503</blockquote> 7504 7505<p> 7506DE 21 7507</p> 7508 7509<blockquote> 7510The specification for bind claims twice that "the values and types for 7511the bound arguments v1, v2, ..., vN are determined as specified below". 7512No such specification appears to exist. 7513</blockquote> 7514 7515<p><i>[ 7516San Francisco: 7517]</i></p> 7518 7519 7520<blockquote> 7521Howard to provide wording. 7522</blockquote> 7523 7524<p><i>[ 7525Post Summit Alisdair and Howard provided wording. 7526]</i></p> 7527 7528 7529<blockquote> 7530<p> 7531Several issues are being combined in this resolution. They are all touching the 7532same words so this is an attempt to keep one issue from stepping on another, and 7533a place to see the complete solution in one place. 7534</p> 7535 7536<ol> 7537<li> 7538<tt>bind</tt> needs to be "moved". 7539</li> 7540<li> 754120.7.11.1.3 [func.bind.bind]/p3, p6 and p7 were accidently removed from N2798. 7542</li> 7543<li> 7544Issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#929">929</a> argues for a way to pass by && for 7545efficiency but retain the decaying behavior of pass by value for the 7546<tt>thread</tt> constructor. That same solution is applicable here. 7547</li> 7548</ol> 7549</blockquote> 7550 7551<p><i>[ 7552Batavia (2009-05): 7553]</i></p> 7554 7555<blockquote> 7556<p> 7557We were going to recommend moving this issue to Tentatively Ready 7558until we noticed potential overlap with issue 816 (q.v.). 7559</p> 7560<p> 7561Move to Open, 7562and recommend both issues be considered together 7563(and possibly merged). 7564</p> 7565</blockquote> 7566 7567<p><i>[ 75682009-07 Frankfurt: 7569]</i></p> 7570 7571 7572<blockquote> 7573The proposed resolution uses concepts. Leave Open. 7574</blockquote> 7575 7576<p><i>[ 75772009-10 Santa Cruz: 7578]</i></p> 7579 7580 7581<blockquote> 7582Leave as Open. Howard to provide deconceptified wording. 7583</blockquote> 7584 7585<p><i>[ 75862009-11-07 Howard updates wording. 7587]</i></p> 7588 7589 7590 7591 7592<p><b>Proposed resolution:</b></p> 7593<p> 7594Change 20.7 [function.objects] p2: 7595</p> 7596 7597<blockquote><pre>template<class F<del>n</del>, class... <del>Types</del> <ins>BoundArgs</ins>> 7598 <i>unspecified</i> bind(F<del>n</del><ins>&&</ins>, <del>Types</del> <ins>BoundArgs&&</ins>...); 7599template<class R, class F<del>n</del>, class... <del>Types</del> <ins>BoundArgs</ins>> 7600 <i>unspecified</i> bind(F<del>n</del><ins>&&</ins>, <del>Types</del> <ins>BoundArgs&&</ins>...); 7601</pre></blockquote> 7602 7603<p> 7604Change 20.7.11.1.3 [func.bind.bind]: 7605</p> 7606 7607<blockquote> 7608<p><ins> 7609Within this clause: 7610</ins></p> 7611 7612<ul> 7613<li><ins> 7614Let <tt>FD</tt> be a synonym for the type <tt>decay<F>::type</tt>. 7615</ins></li> 7616<li><ins> 7617Let <tt>fd</tt> be an lvalue of type <tt>FD</tt> constructed from 7618<tt>std::forward<F>(f)</tt>. 7619</ins></li> 7620<li><ins> 7621Let <tt>Ti</tt> be a synonym for the i<sup><i>th</i></sup> type in the 7622parameter pack <tt>BoundArgs</tt>. 7623</ins></li> 7624<li><ins> 7625Let <tt>TiD</tt> be a synonym for the type <tt>decay<Ti>::type</tt>. 7626</ins></li> 7627<li><ins> 7628Let <tt>ti</tt> be the i<sup><i>th</i></sup> argument in <tt>bound_args</tt>. 7629</ins></li> 7630<li><ins> 7631Let <tt>tid</tt> be an lvalue of type <tt>TiD</tt> constructed from 7632<tt>std::forward<Ti>(ti)</tt>. 7633</ins></li> 7634</ul> 7635 7636<pre>template<class F, class... BoundArgs> 7637 <i>unspecified</i> bind(F<ins>&&</ins> f, BoundArgs<ins>&&</ins>... bound_args); 7638</pre> 7639 7640<blockquote> 7641<p> 7642-1- <i>Requires:</i> 7643<ins><tt>is_constructible<FD, F>::value</tt> 7644shall be <tt>true</tt>.</ins> 7645<ins><tt>is_constructible<TiD, Ti>::value</tt> 7646shall be <tt>true</tt></ins>. 7647<del><tt>F</tt> and each <tt>Ti</tt> in 7648<tt>BoundArgs</tt> shall be CopyConstructible.</del> 7649<tt><i>INVOKE</i>(f<ins>d</ins>, w1, w2, ..., wN)</tt> (20.7.2 [func.require]) shall be a valid expression for some values 7650<i>w1, w2, ..., wN</i>, where <tt>N == sizeof...(bound_args)</tt>. 7651</p> 7652<p> 7653-2- <i>Returns:</i> A forwarding call wrapper <tt>g</tt> with a weak 7654result type (20.7.2 [func.require]). The effect of <tt>g(u1, u2, 7655..., uM)</tt> shall be <tt><i>INVOKE</i>(f<ins>d</ins>, v1, v2, ..., vN, 7656result_of<F<ins>D</ins> <i>cv</i> (V1, V2, ..., VN)>::type)</tt>, where 7657<i>cv</i> represents the <i>cv</i>-qualifiers of <tt>g</tt> and the 7658values and types of the bound arguments <tt>v1, v2, ..., vN</tt> are 7659determined as specified below. 7660<ins>The copy constructor and move constructor of the forwarding call wrapper shall throw an 7661exception if and only if the corresponding constructor of <tt>FD</tt> or any of the types 7662<tt>TiD</tt> throw an exception.</ins> 7663</p> 7664<p> 7665-3- <i>Throws:</i> Nothing unless the <del>copy</del> 7666construct<ins>ion</ins><del>or</del> of 7667<tt><del>F</del><ins>fd</ins></tt> or of one of the <ins>values 7668<tt>tid</tt></ins> <del>types in the <tt>BoundArgs...</tt> pack 7669expansion</del> throws an exception. 7670</p> 7671<p> 7672<ins> 7673<i>Remarks:</i> The <i>unspecified</i> return type shall be 7674<tt>MoveConstructible</tt>. If all of <tt>FD</tt> and <tt>TiD</tt> are 7675<tt>CopyConstructible</tt> then the <i>unspecified</i> return type shall 7676be <tt>CopyConstructible</tt>. [<i>Note:</i> This implies that all of 7677<tt>FD</tt> and <tt>TiD</tt> shall be <tt>MoveConstructible</tt> — 7678<i>end note</i>] 7679</ins> 7680</p> 7681</blockquote> 7682 7683<pre>template<class R, class F, class... BoundArgs> 7684 <i>unspecified</i> bind(F<ins>&&</ins> f, BoundArgs<ins>&&</ins>... bound_args); 7685</pre> 7686 7687<blockquote> 7688<p> 7689-4- <i>Requires:</i> 7690<ins><tt>is_constructible<FD, F>::value</tt> 7691shall be <tt>true</tt>.</ins> 7692<ins><tt>is_constructible<TiD, Ti>::value</tt> 7693shall be <tt>true</tt></ins>. 7694<del><tt>F</tt> and each <tt>Ti</tt> in 7695<tt>BoundArgs</tt> shall be CopyConstructible.</del> 7696<tt><i>INVOKE</i>(f<ins>d</ins>, w1, 7697w2, ..., wN)</tt> shall be a valid expression for some values <i>w1, w2, 7698..., wN</i>, where <tt>N == sizeof...(bound_args)</tt>. 7699</p> 7700<p> 7701-5- <i>Returns:</i> A forwarding call wrapper <tt>g</tt> with a nested 7702type <tt>result_type</tt> defined as a synonym for <tt>R</tt>. The 7703effect of <tt>g(u1, u2, ..., uM)</tt> shall be <tt><i>INVOKE</i>(f<ins>d</ins>, v1, 7704v2, ..., vN, R)</tt>, where the values and types of the bound arguments 7705<tt>v1, v2, ..., vN</tt> are determined as specified below. 7706<ins>The copy constructor and move constructor of the forwarding call wrapper shall throw an 7707exception if and only if the corresponding constructor of <tt>FD</tt> or any of the types 7708<tt>TiD</tt> throw an exception.</ins> 7709</p> 7710<p> 7711-6- <i>Throws:</i> Nothing unless the <del>copy</del> 7712construct<ins>ion</ins><del>or</del> of 7713<tt><del>F</del><ins>fd</ins></tt> or of one of the <ins>values 7714<tt>tid</tt></ins> <del>types in the <tt>BoundArgs...</tt> pack 7715expansion</del> throws an exception. 7716</p> 7717<p> 7718<ins> 7719<i>Remarks:</i> The <i>unspecified</i> return type shall be 7720<tt>MoveConstructible</tt>. If all of <tt>FD</tt> and <tt>TiD</tt> are 7721<tt>CopyConstructible</tt> then the <i>unspecified</i> return type shall 7722be <tt>CopyConstructible</tt>. [<i>Note:</i> This implies that all of 7723<tt>FD</tt> and <tt>TiD</tt> shall be <tt>MoveConstructible</tt> — 7724<i>end note</i>] 7725</ins> 7726</p> 7727</blockquote> 7728 7729<p> 7730-7- The values of the <i>bound arguments</i> <tt>v1, v2, ..., vN</tt> and 7731their corresponding types <tt>V1, V2, ..., VN</tt> depend on the type<ins>s 7732<tt>TiD</tt> derived from</ins> 7733<del>of the corresponding argument <tt>ti</tt> in <tt>bound_args</tt> of type 7734<tt>Ti</tt> in <tt>BoundArgs</tt> in</del> 7735the call to <tt>bind</tt> and the 7736<i>cv</i>-qualifiers <i>cv</i> of the call wrapper <tt>g</tt> as 7737follows: 7738</p> 7739 7740<ul> 7741<li> 7742if <tt><del>ti</del> <ins>TiD</ins></tt> <del>is of</del> <ins>has</ins> 7743type <tt>reference_wrapper<T></tt> the argument is 7744<tt>ti<ins>d</ins>.get()</tt> and its type <tt>Vi</tt> is 7745<tt>T&</tt>; 7746</li> 7747<li> 7748if the value of 7749<tt>std::is_bind_expression<Ti<ins>D</ins>>::value</tt> is 7750<tt>true</tt> the argument is <tt>ti<ins>d</ins>(u1, u2, ..., uM)</tt> 7751and its type <tt>Vi</tt> is <tt>result_of<Ti<ins>D</ins> <i>cv</i> 7752(U1&, U2&, ..., UM&)>::type</tt>; 7753</li> 7754<li> 7755if the value <tt>j</tt> of 7756<tt>std::is_placeholder<Ti<ins>D</ins>>::value</tt> is not zero 7757the argument is <tt>std::forward<Uj>(uj)</tt> and its type 7758<tt>Vi</tt> is <tt>Uj&&</tt>; 7759</li> 7760<li> 7761otherwise the value is <tt>ti<ins>d</ins></tt> and its type <tt>Vi</tt> 7762is <tt>Ti<ins>D</ins> <i>cv</i> &</tt>. 7763</li> 7764</ul> 7765 7766</blockquote> 7767 7768 7769 7770 7771 7772 7773<hr> 7774<h3><a name="819"></a>819. rethrow_if_nested</h3> 7775<p><b>Section:</b> 18.8.6 [except.nested] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 7776 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2008-03-25 <b>Last modified:</b> 2009-10-23</p> 7777<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#except.nested">active issues</a> in [except.nested].</p> 7778<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#except.nested">issues</a> in [except.nested].</p> 7779<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 7780<p><b>Discussion:</b></p> 7781<p> 7782Looking at the wording I submitted for <tt>rethrow_if_nested</tt>, I don't think I 7783got it quite right. 7784</p> 7785 7786<p> 7787The current wording says: 7788</p> 7789 7790<blockquote> 7791<pre>template <class E> void rethrow_if_nested(const E& e); 7792</pre> 7793<blockquote> 7794<p> 7795<i>Effects:</i> Calls <tt>e.rethrow_nested()</tt> only if <tt>e</tt> 7796is publicly derived from <tt>nested_exception</tt>. 7797</p> 7798</blockquote> 7799</blockquote> 7800 7801<p> 7802This is trying to be a bit subtle, by requiring <tt>e</tt> (not <tt>E</tt>) to be publicly 7803derived from <tt>nested_exception</tt> the idea is that a <tt>dynamic_cast</tt> would be 7804required to be sure. Unfortunately, if <tt>e</tt> is dynamically but not statically 7805derived from <tt>nested_exception</tt>, <tt>e.rethrow_nested()</tt> is ill-formed. 7806</p> 7807 7808<p><i>[ 7809San Francisco: 7810]</i></p> 7811 7812 7813<blockquote> 7814Alisdair was volunteered to provide wording. 7815</blockquote> 7816 7817<p><i>[ 78182009-10 Santa Cruz: 7819]</i></p> 7820 7821 7822<blockquote> 7823Leave as Open. Alisdair to provide wording. 7824</blockquote> 7825 7826 7827 7828<p><b>Proposed resolution:</b></p> 7829 7830 7831 7832 7833 7834<hr> 7835<h3><a name="834"></a>834. Unique_ptr::pointer requirements underspecified</h3> 7836<p><b>Section:</b> 20.8.14.2 [unique.ptr.single] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 7837 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2008-05-14 <b>Last modified:</b> 2009-10-26</p> 7838<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#unique.ptr.single">active issues</a> in [unique.ptr.single].</p> 7839<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#unique.ptr.single">issues</a> in [unique.ptr.single].</p> 7840<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 7841<p><b>Discussion:</b></p> 7842<p> 7843Issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#673">673</a> (including recent updates by <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#821">821</a>) proposes a useful 7844extension point for <tt>unique_ptr</tt> by granting support for an optional 7845<tt>deleter_type::pointer</tt> to act as pointer-like replacement for <tt>element_type*</tt> 7846(In the following: <tt>pointer</tt>). 7847</p> 7848<p> 7849Unfortunately no requirements are specified for the type <tt>pointer</tt> which has 7850impact on at least two key features of <tt>unique_ptr</tt>: 7851</p> 7852 7853<ol> 7854<li>Operational fail-safety.</li> 7855<li>(Well-)Definedness of expressions.</li> 7856</ol> 7857 7858<p> 7859<tt>Unique_ptr</tt> specification makes great efforts to require that essentially *all* 7860operations cannot throw and therefore adds proper wording to the affected 7861operations of the deleter as well. If user-provided <tt>pointer</tt>-emulating types 7862("smart pointers") will be allowed, either *all* throw-nothing clauses have to 7863be replaced by weaker "An exception is thrown only if <tt>pointer</tt>'s {op} throws 7864an exception"-clauses or it has to be said explicitly that all used 7865operations of 7866<tt>pointer</tt> are required *not* to throw. I understand the main focus of <tt>unique_ptr</tt> 7867to be as near as possible to the advantages of native pointers which cannot 7868fail and thus strongly favor the second choice. Also, the alternative position 7869would make it much harder to write safe and simple template code for 7870<tt>unique_ptr</tt>. Additionally, I assume that a general statement need to be given 7871that all of the expressions of <tt>pointer</tt> used to define semantics are required to 7872be well-formed and well-defined (also as back-end for <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#762">762</a>). 7873</p> 7874 7875<p><i>[ 7876Sophia Antipolis: 7877]</i></p> 7878 7879 7880<blockquote> 7881<p> 7882Howard: We maybe need a core concept <tt>PointerLike</tt>, but we don't need the 7883arithmetic (see <tt>shared_ptr</tt> vs. <tt>vector<T>::iterator</tt>. 7884</p> 7885<p> 7886Howard will go through and enumerate the individual requirements wrt. <tt>pointer</tt> for each member function. 7887</p> 7888</blockquote> 7889 7890<p><i>[ 78912009-07 Frankfurt: 7892]</i></p> 7893 7894 7895<blockquote> 7896Move to Ready. 7897</blockquote> 7898 7899<p><i>[ 79002009-10-15 Alisdair pulls from Ready: 7901]</i></p> 7902 7903 7904<blockquote> 7905<p> 7906I hate to pull an issue out of Ready status, but I don't think 834 is 7907fully baked yet. 7908</p> 7909 7910<p> 7911For reference the proposed resolution is to add the following words: 7912</p> 7913 7914<blockquote> 7915<tt>unique_ptr<T, D>::pointer</tt>'s operations shall be 7916well-formed, shall have well defined behavior, and shall not throw 7917exceptions. 7918</blockquote> 7919 7920<p> 7921This leaves me with a big question : which operations? 7922</p> 7923 7924<p> 7925Are all pointer operations required to be nothrow, including operations 7926that have nothing to do with interactions with <tt>unique_ptr</tt>? This was 7927much simpler with concepts where we could point to operations within a 7928certain concept, and so nail down the interactions. 7929</p> 7930</blockquote> 7931 7932<p><i>[ 79332009-10-15 Daniel adds: 7934]</i></p> 7935 7936 7937<blockquote> 7938I volunteer to prepare a more fine-grained solution, but I would like 7939to ask for feedback that helps me doing so. If this question is asked 7940early in the meeting I might be able to fix it within the week, but I 7941cannot promise that now. 7942</blockquote> 7943 7944<p><i>[ 79452009-10 Santa Cruz: 7946]</i></p> 7947 7948 7949<blockquote> 7950Leave in open. Daniel to provide wording as already suggested. 7951</blockquote> 7952 7953 7954 7955 7956<p><b>Proposed resolution:</b></p> 7957<p> 7958Add the following sentence just at the end of the newly proposed 795920.8.14.2 [unique.ptr.single]/p. 3: 7960</p> 7961 7962<blockquote> 7963<tt>unique_ptr<T, D>::pointer</tt>'s operations shall be well-formed, shall have well 7964defined behavior, and shall not throw exceptions. 7965</blockquote> 7966 7967 7968 7969 7970 7971<hr> 7972<h3><a name="835"></a>835. tying two streams together (correction to DR 581)</h3> 7973<p><b>Section:</b> 27.5.4.2 [basic.ios.members] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 7974 <b>Submitter:</b> Martin Sebor <b>Opened:</b> 2008-05-17 <b>Last modified:</b> 2009-10-20</p> 7975<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#basic.ios.members">active issues</a> in [basic.ios.members].</p> 7976<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#basic.ios.members">issues</a> in [basic.ios.members].</p> 7977<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 7978<p><b>Discussion:</b></p> 7979 <p> 7980 7981The fix for 7982issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#581">581</a>, 7983now integrated into the working paper, overlooks a couple of minor 7984problems. 7985 7986 </p> 7987 <p> 7988 7989First, being an unformatted function once again, <code>flush()</code> 7990is required to create a sentry object whose constructor must, among 7991other things, flush the tied stream. When two streams are tied 7992together, either directly or through another intermediate stream 7993object, flushing one will also cause a call to <code>flush()</code> on 7994the other tied stream(s) and vice versa, ad infinitum. The program 7995below demonstrates the problem. 7996 7997 </p> 7998 <p> 7999 8000Second, as Bo Persson notes in his 8001comp.lang.c++.moderated <a href="http://groups.google.com/group/comp.lang.c++.moderated/tree/browse_frm/thread/f2187794e9cc036d/305df31dc583054a">post</a>, 8002for streams with the <code>unitbuf</code> flag set such 8003as <code>std::stderr</code>, the destructor of the sentry object will 8004again call <code>flush()</code>. This seems to create an infinite 8005recursion for <code>std::cerr << std::flush;</code> 8006 8007 </p> 8008 <blockquote> 8009 <pre>#include <iostream> 8010 8011int main () 8012{ 8013 std::cout.tie (&std::cerr); 8014 std::cerr.tie (&std::cout); 8015 std::cout << "cout\n"; 8016 std::cerr << "cerr\n"; 8017} 8018</pre> 8019</blockquote> 8020 8021<p><i>[ 8022Batavia (2009-05): 8023]</i></p> 8024 8025<blockquote> 8026We agree with the proposed resolution. 8027Move to Review. 8028</blockquote> 8029 8030<p><i>[ 80312009-05-26 Daniel adds: 8032]</i></p> 8033 8034 8035<blockquote> 8036<p> 8037I think that the most recently suggested change in 803827.7.2.4 [ostream::sentry] need some further word-smithing. As 8039written, it would make the behavior undefined, if under 8040conditions when <tt>pubsync()</tt> should be called, but when 8041in this scenario <tt>os.rdbuf()</tt> returns 0. 8042</p> 8043<p> 8044This case is explicitly handled in <tt>flush()</tt> and needs to be 8045taken care of. My suggested fix is: 8046</p> 8047 8048<blockquote> 8049If <tt>((os.flags() & ios_base::unitbuf) && !uncaught_exception()</tt> 8050<ins><tt>&& os.rdbuf() != 0</tt></ins>) is true, calls <del><tt>os.flush()</tt></del> 8051<ins><tt>os.rdbuf()->pubsync()</tt></ins>. 8052</blockquote> 8053 8054<p> 8055Two secondary questions are: 8056</p> 8057 8058<ol> 8059<li> 8060Should <tt>pubsync()</tt> be invoked in any case or shouldn't a 8061base requirement for this trial be that <tt>os.good() == true</tt> 8062as required in the original <tt>flush()</tt> case? 8063</li> 8064<li> 8065Since <tt>uncaught_exception()</tt> is explicitly tested, shouldn't 8066a return value of -1 of <tt>pubsync()</tt> produce <tt>setstate(badbit)</tt> 8067(which may throw <tt>ios_base::failure</tt>)? 8068</li> 8069</ol> 8070</blockquote> 8071 8072<p><i>[ 80732009-07 Frankfurt: 8074]</i></p> 8075 8076 8077<blockquote> 8078<p> 8079Daniel volunteered to modify the proposed resolution to address his two questions. 8080</p> 8081<p> 8082Move back to Open. 8083</p> 8084</blockquote> 8085 8086<p><i>[ 80872009-07-26 Daniel provided wording. Moved to Review. 8088]</i></p> 8089 8090 8091<p><i>[ 80922009-10-13 Daniel adds: 8093]</i></p> 8094 8095 8096<blockquote> 8097This proposed wording is written to match the outcome 8098of <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#397">397</a>. 8099</blockquote> 8100 8101<p><i>[ 81022009 Santa Cruz: 8103]</i></p> 8104 8105 8106<blockquote> 8107Move to Open. Martin to propose updated wording that will also resolve 8108issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#397">397</a> consistently. 8109</blockquote> 8110 8111 8112 8113<p><b>Proposed resolution:</b></p> 8114<p><i>[ 8115based on 8116<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2960.pdf">N2960</a> 8117numbering 8118]</i></p> 8119 8120 8121<ol> 8122<li> 8123<p> 8124Just before 27.5.4.2 [basic.ios.members]/2 insert a new paragraph: 8125</p> 8126 8127<blockquote> 8128<ins><i>Requires:</i> If <tt>(tiestr != 0)</tt> is <tt>true</tt>, <tt>tiestr</tt> must not be reachable 8129by traversing the linked list of tied stream objects starting from 8130<tt>tiestr->tie()</tt>.</ins> 8131</blockquote> 8132</li> 8133 8134<li> 8135<p> 8136Change 27.7.2.4 [ostream::sentry]/4 as indicated: 8137</p> 8138 8139<blockquote> 8140If <tt>((os.flags() & ios_base::unitbuf) && !uncaught_exception()<ins>&& 8141os.good()</ins>)</tt> is <tt>true</tt>, calls <del><tt>os.flush()</tt></del> 8142<ins><tt>os.rdbuf()->pubsync()</tt>. If that function returns -1 sets 8143<tt>badbit</tt> in <tt>os.rdstate()</tt> without propagating an exception</ins>. 8144</blockquote> 8145</li> 8146 8147</ol> 8148 8149 8150 8151 8152 8153 8154<hr> 8155<h3><a name="836"></a>836. 8156 effects of <code>money_base::space</code> and 8157 <code>money_base::none</code> on <code>money_get</code> 8158 </h3> 8159<p><b>Section:</b> 22.4.6.1.2 [locale.money.get.virtuals] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 8160 <b>Submitter:</b> Martin Sebor <b>Opened:</b> 2008-05-17 <b>Last modified:</b> 2009-10-21</p> 8161<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#locale.money.get.virtuals">issues</a> in [locale.money.get.virtuals].</p> 8162<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 8163<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#670">670</a></p> 8164<p><b>Discussion:</b></p> 8165 8166 <p> 8167 8168In paragraph 2, 22.4.6.1.2 [locale.money.get.virtuals] specifies the following: 8169 8170 </p> 8171 <blockquote> 8172 8173Where <code>space</code> or <code>none</code> appears in the format 8174pattern, except at the end, optional white space (as recognized 8175by <code>ct.is</code>) is consumed after any required space. 8176 8177 </blockquote> 8178 <p> 8179 8180This requirement can be (and has been) interpreted two mutually 8181exclusive ways by different readers. One possible interpretation 8182is that: 8183 8184 </p> 8185 <blockquote> 8186 <ol> 8187 <li> 8188 8189where <code>money_base::space</code> appears in the format, at least 8190one space is required, and 8191 8192 </li> 8193 <li> 8194 8195where <code>money_base::none</code> appears in the format, space is 8196allowed but not required. 8197 8198 </li> 8199 </ol> 8200 </blockquote> 8201 <p> 8202 8203The other is that: 8204 8205 </p> 8206 <blockquote> 8207 8208where either <code>money_base::space</code> or <code>money_base::none</code> appears in the format, white space is optional. 8209 8210 </blockquote> 8211 8212<p><i>[ 8213San Francisco: 8214]</i></p> 8215 8216 8217<blockquote> 8218Martin will revise the proposed resolution. 8219</blockquote> 8220 8221<p><i>[ 82222009-07 Frankfurt: 8223]</i></p> 8224 8225 8226<blockquote> 8227<p> 8228There is a noun missing from the proposed resolution. It's not clear 8229that the last sentence would be helpful, even if the word were not 8230missing: 8231</p> 8232<blockquote> 8233In either case, any required MISSINGWORD followed by all optional whitespace (as recognized by ct.is()) is consumed. 8234</blockquote> 8235<p> 8236Strike this sentence and move to Review. 8237</p> 8238 8239<p><i>[ 8240Howard: done. 8241]</i></p> 8242 8243</blockquote> 8244 8245<p><i>[ 82462009-10 Santa Cruz: 8247]</i></p> 8248 8249 8250<blockquote> 8251Move to Ready. 8252</blockquote> 8253 8254 8255 8256 <p><b>Proposed resolution:</b></p> 8257 <p> 8258 8259I propose to change the text to make it clear that the first 8260interpretation is intended, that is, to make following change to 826122.4.6.1.2 [locale.money.get.virtuals], p2: 8262 8263 </p> 8264 8265 <blockquote> 8266 8267When <code><ins>money_base::</ins>space</code> 8268or <code><ins>money_base::</ins>none</code> appears <ins>as the last 8269element </ins>in the format pattern, <del>except at the end, optional 8270white space (as recognized by <code>ct.is</code>) is consumed after 8271any required space.</del> <ins>no white space is consumed. Otherwise, 8272where <code>money_base::space</code> appears in any of the initial 8273elements of the format pattern, at least one white space character is 8274required. Where <code>money_base::none</code> appears in any of the 8275initial elements of the format pattern, white space is allowed but not 8276required.</ins> 8277If <code>(str.flags() & str.showbase)</code> is <code>false</code>, ... 8278 8279 </blockquote> 8280 8281 8282 8283 8284<hr> 8285<h3><a name="854"></a>854. <tt>default_delete</tt> converting constructor underspecified</h3> 8286<p><b>Section:</b> 20.8.14.1.1 [unique.ptr.dltr.dflt] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 8287 <b>Submitter:</b> Howard Hinnant <b>Opened:</b> 2008-06-18 <b>Last modified:</b> 2009-10-21</p> 8288<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 8289<p><b>Discussion:</b></p> 8290<p> 8291No relationship between <tt>U</tt> and <tt>T</tt> in the converting constructor for <tt>default_delete</tt> template. 8292</p> 8293<p> 8294Requirements: <tt>U*</tt> is convertible to <tt>T*</tt> and <tt>has_virtual_destructor<T></tt>; 8295the latter should also become a concept. 8296</p> 8297<p> 8298Rules out cross-casting. 8299</p> 8300<p> 8301The requirements for <tt>unique_ptr</tt> conversions should be the same as those on the deleter. 8302</p> 8303 8304<p><i>[ 8305Howard adds 2008-11-26: 8306]</i></p> 8307 8308 8309<blockquote> 8310<p> 8311I believe we need to be careful to not outlaw the following use case, and 8312I believe the current proposed wording 8313(<tt>requires Convertible<U*, T*> && HasVirtualDestructor<T></tt>) does so: 8314</p> 8315 8316<blockquote><pre>#include <memory> 8317 8318int main() 8319{ 8320 std::unique_ptr<int> p1(new int(1)); 8321 std::unique_ptr<const int> p2(move(p1)); 8322 int i = *p2; 8323<font color="#c80000">// *p2 = i; // should not compile</font> 8324} 8325</pre></blockquote> 8326 8327<p> 8328I've removed "<tt>&& HasVirtualDestructor<T></tt>" from the 8329<tt>requires</tt> clause in the proposed wording. 8330</p> 8331 8332</blockquote> 8333 8334<p><i>[ 8335Post Summit: 8336]</i></p> 8337 8338 8339<blockquote> 8340<p> 8341Alisdair: This issue has to stay in review pending a paper constraining 8342<tt>unique_ptr</tt>. 8343</p> 8344<p> 8345Consensus: We agree with the resolution, but <tt>unique_ptr</tt> needs 8346to be constrained, too. 8347</p> 8348<p> 8349Recommend Keep in Review. 8350</p> 8351</blockquote> 8352 8353<p><i>[ 8354Batavia (2009-05): 8355]</i></p> 8356 8357<blockquote> 8358Keep in Review status for the reasons cited. 8359</blockquote> 8360 8361<p><i>[ 83622009-07 Frankfurt: 8363]</i></p> 8364 8365 8366<blockquote> 8367<p> 8368The proposed resolution uses concepts. Howard needs to rewrite the 8369proposed resolution. 8370</p> 8371<p> 8372Move back to Open. 8373</p> 8374</blockquote> 8375 8376<p><i>[ 83772009-07-26 Howard provided rewritten proposed wording and moved to Review. 8378]</i></p> 8379 8380 8381<p><i>[ 83822009-10 Santa Cruz: 8383]</i></p> 8384 8385 8386<blockquote> 8387Move to Ready. 8388</blockquote> 8389 8390 8391 8392<p><b>Proposed resolution:</b></p> 8393<p> 8394Add after 20.8.14.1.1 [unique.ptr.dltr.dflt], p1: 8395</p> 8396 8397<blockquote><pre>template <class U> default_delete(const default_delete<U>& other); 8398</pre> 8399<blockquote> 8400<p> 8401-1- <i>Effects:</i> ... 8402</p> 8403<p><ins> 8404<i>Remarks:</i> This constructor shall participate in overload resolution 8405if and only if <tt>U*</tt> is implicitly convertible to <tt>T*</tt>. 8406</ins></p> 8407</blockquote> 8408</blockquote> 8409 8410 8411 8412 8413 8414 8415<hr> 8416<h3><a name="860"></a>860. Floating-Point State</h3> 8417<p><b>Section:</b> 26 [numerics] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 8418 <b>Submitter:</b> Lawrence Crowl <b>Opened:</b> 2008-06-23 <b>Last modified:</b> 2009-10-23</p> 8419<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#numerics">issues</a> in [numerics].</p> 8420<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 8421<p><b>Discussion:</b></p> 8422<p> 8423There are a number of functions that affect the floating point state. 8424These function need to be thread-safe, but I'm unsure of the right 8425approach in the standard, as we inherit them from C. 8426</p> 8427 8428<p><i>[ 8429San Francisco: 8430]</i></p> 8431 8432 8433<blockquote> 8434<p> 8435Nick: I think we already say that these functions do not introduce data 8436races; see 17.6.5.6/20 8437</p> 8438<p> 8439Pete: there's more to it than not introducing data races; are these 8440states maintained per thread? 8441</p> 8442<p> 8443Howard: 21.5/14 says that strtok and strerror are not required to avoid 8444data races, and 20.9/2 says the same about asctime, gmtime, ctime, and 8445gmtime. 8446</p> 8447<p> 8448Nick: POSIX has a list of not-safe functions. All other functions are 8449implicitly thread safe. 8450</p> 8451<p> 8452Lawrence is to form a group between meetings to attack this issue. Nick 8453and Tom volunteered to work with Lawrence. 8454</p> 8455<p> 8456Move to Open. 8457</p> 8458</blockquote> 8459 8460<p><i>[ 8461Post Summit: 8462]</i></p> 8463 8464 8465<blockquote> 8466<p> 8467Hans: Sane oses seem ok. Sensible thing is implementable and makes sense. 8468</p> 8469<p> 8470Nick: Default wording seems to cover this? Hole in POSIX, these 8471functions need to be added to list of thread-unsafe functions. 8472</p> 8473<p> 8474Lawrence: Not sufficient, not "thread-safe" per our definition, but 8475think of state as a thread-local variable. Need something like "these 8476functions only affect state in the current thread." 8477</p> 8478<p> 8479Hans: Suggest the following wording: "The floating point environment is 8480maintained per-thread." 8481</p> 8482<p> 8483Walter: Any other examples of state being thread safe that are not 8484already covered elsewhere? 8485</p> 8486<p> 8487Have thread unsafe functions paper which needs to be updated. Should 8488just fold in 26.3 [cfenv] functions. 8489</p> 8490<p> 8491Recommend Open. Lawrence instead suggests leaving it open until we have 8492suitable wording that may or may not include the thread local 8493commentary. 8494</p> 8495</blockquote> 8496 8497<p><i>[ 84982009-09-23 Hans provided wording. 8499]</i></p> 8500 8501 8502<blockquote> 8503If I understand the history correctly, Nick, as the Posix liaison, 8504should probably get a veto on this, since I think it came from Posix (?) 8505via WG14 and should probably really be addressed there (?). But I think 8506we are basically in agreement that there is no other sane way to do 8507this, and hence we don't have to worry too much about stepping on toes. 8508As far as I can tell, this same issue also exists in the latest Posix 8509standard (?). 8510</blockquote> 8511 8512<p><i>[ 85132009-10 Santa Cruz: 8514]</i></p> 8515 8516 8517<blockquote> 8518Moved to Ready. 8519</blockquote> 8520 8521 8522 8523<p><b>Proposed resolution:</b></p> 8524<p> 8525Add at the end of 26.3.1 [cfenv.syn]: 8526</p> 8527 8528<blockquote> 8529<p> 85302 The header defines all functions, types, and macros the same as C99 7.6. 8531</p> 8532 8533<p><ins> 8534A separate floating point environment shall be maintained for each 8535thread. Each function accesses the environment corresponding to its 8536calling thread. 8537</ins></p> 8538</blockquote> 8539 8540 8541 8542 8543 8544<hr> 8545<h3><a name="861"></a>861. Incomplete specification of EqualityComparable for std::forward_list</h3> 8546<p><b>Section:</b> 23.2 [container.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 8547 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2008-06-24 <b>Last modified:</b> 2009-10-24</p> 8548<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#container.requirements">active issues</a> in [container.requirements].</p> 8549<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#container.requirements">issues</a> in [container.requirements].</p> 8550<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 8551<p><b>Discussion:</b></p> 8552<p> 8553Table 89, Container requirements, defines <tt>operator==</tt> in terms of the container 8554member function <tt>size()</tt> and the algorithm <tt>std::equal</tt>: 8555</p> 8556 8557<blockquote> 8558<tt>==</tt> is an equivalence relation. <tt>a.size() == b.size() && 8559equal(a.begin(), a.end(), b.begin()</tt> 8560</blockquote> 8561 8562<p> 8563The new container <tt>forward_list</tt> does not provide a <tt>size</tt> member function 8564by design but does provide <tt>operator==</tt> and <tt>operator!=</tt> without specifying it's semantic. 8565</p> 8566<p> 8567Other parts of the (sequence) container requirements do also depend on 8568<tt>size()</tt>, e.g. <tt>empty()</tt> 8569or <tt>clear()</tt>, but this issue explicitly attempts to solve the missing 8570<tt>EqualityComparable</tt> specification, 8571because of the special design choices of <tt>forward_list</tt>. 8572</p> 8573<p> 8574I propose to apply one of the following resolutions, which are described as: 8575</p> 8576 8577<ol type="A"> 8578<li> 8579Provide a definition, which is optimal for this special container without 8580previous size test. This choice prevents two <tt>O(N)</tt> calls of <tt>std::distance()</tt> 8581with the corresponding container ranges and instead uses a special 8582<tt>equals</tt> implementation which takes two container ranges instead of 1 1/2. 8583</li> 8584<li> 8585The simple fix where the usual test is adapted such that <tt>size()</tt> is replaced 8586by <tt>distance</tt> with corresponding performance disadvantages. 8587</li> 8588</ol> 8589<p> 8590Both proposal choices are discussed, the preferred choice of the author is 8591to apply (A). 8592</p> 8593 8594<p><i>[ 8595San Francisco: 8596]</i></p> 8597 8598 8599<blockquote> 8600<p> 8601There's an Option C: change the requirements table to use distance(). 8602</p> 8603<p> 8604LWG found Option C acceptable. 8605</p> 8606<p> 8607Martin will draft the wording for Option C. 8608</p> 8609</blockquote> 8610 8611<p><i>[ 8612post San Francisco: 8613]</i></p> 8614 8615 8616<blockquote> 8617Martin provided wording for Option C. 8618</blockquote> 8619 8620<p><i>[ 86212009-07 Frankfurt 8622]</i></p> 8623 8624 8625<blockquote> 8626<p> 8627Other operational semantics (see, for example, Tables 82 and 83) are 8628written in terms of a container's size() member. Daniel to update 8629proposed resolution C. 8630</p> 8631<p><i>[ 8632Howard: Commented out options A and B. 8633]</i></p> 8634 8635</blockquote> 8636 8637<p><i>[ 86382009-07-26 Daniel updated proposed resolution C. 8639]</i></p> 8640 8641 8642<p><i>[ 86432009-10 Santa Cruz: 8644]</i></p> 8645 8646 8647<blockquote> 8648Mark NAD Editorial. Addressed by 8649<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2986.pdf">N2986</a>. 8650</blockquote> 8651 8652<p><i>[ 86532009-10 Santa Cruz: 8654]</i></p> 8655 8656 8657<blockquote> 8658Reopened. 8659<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2986.pdf">N2986</a> 8660was rejected in full committee on procedural grounds. 8661</blockquote> 8662 8663 8664 8665<p><b>Proposed resolution:</b></p> 8666 8667 8668<p> 8669Option (C): 8670</p> 8671<blockquote> 8672 8673<p><i>[ 8674The changes are relative to 8675<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2914.pdf">N2914</a> 8676but concept-free. 8677]</i></p> 8678 8679 8680<ol> 8681<li> 8682<p> 8683In 23.2.1 [container.requirements.general] change Table 80 -- Container requirements as indicated: 8684</p> 8685 8686<ol type="a"> 8687<li> 8688<p> 8689Change the text in the Assertion/note column in the row for "<tt>X u</tt>;" 8690as follows: 8691</p> 8692 8693<blockquote> 8694post: <tt>u.<del>size() == 0</del><ins>empty() == true</ins></tt> 8695</blockquote> 8696</li> 8697 8698<li> 8699<p> 8700Change the text in the Assertion/note column in the row for "<tt>X();</tt>" 8701as follows: 8702</p> 8703 8704<blockquote> 8705<tt>X().<del>size() == 0</del><ins>empty() == true</ins></tt> 8706</blockquote> 8707</li> 8708 8709<li> 8710<p> 8711Change the text in the Operational Semantics column in the row for 8712"<tt>a == b</tt>" as follows: 8713</p> 8714<blockquote> 8715<tt>==</tt> is an equivalence relation. 8716<tt><del>a.size()</del><ins>distance(a.begin(), a.end())</ins> == 8717 <del>b.size()</del><ins>distance(b.begin(), b.end())</ins> && 8718equal(a.begin(), a.end(), b.begin())</tt> 8719</blockquote> 8720</li> 8721 8722<li> 8723<p> 8724Change the text in the Operational Semantics column in the row for 8725"<tt>a.size()</tt>" as follows: 8726</p> 8727 8728<blockquote> 8729<tt><del>a.end() - a.begin()</del><ins>distance(a.begin(), a.end())</ins></tt> 8730</blockquote> 8731</li> 8732 8733<li> 8734<p> 8735Change the text in the Operational Semantics column in the row for 8736"<tt>a.max_size()</tt>" as follows: 8737</p> 8738 8739<blockquote> 8740<tt><del>size()</del><ins>distance(begin(), end())</ins></tt> of the largest 8741possible container 8742</blockquote> 8743</li> 8744 8745<li> 8746<p> 8747Change the text in the Operational Semantics column in the row for 8748"<tt>a.empty()</tt>" as follows: 8749</p> 8750 8751<blockquote> 8752<tt><del>a.size() == 0</del><ins>a.begin() == a.end()</ins></tt> 8753</blockquote> 8754</li> 8755</ol> 8756</li> 8757 8758<li> 8759<p> 8760In 23.2.1 [container.requirements.general] change Table 82 -- Allocator-aware container requirements as indicated: 8761</p> 8762 8763<ol type="a"> 8764<li> 8765<p> 8766Change the text in the Assertion/note column in the row for "<tt>X() / 8767X u;</tt>" as follows: 8768</p> 8769 8770<blockquote> 8771<i>Requires:</i> <tt>A</tt> is <tt>DefaultConstructible</tt> post: <tt><del>u.size() == 87720</del><ins>u.empty() == true</ins></tt>, <tt>get_allocator() == A()</tt> 8773</blockquote> 8774</li> 8775 8776<li> 8777<p> 8778Change the text in the Assertion/note column in the row for "<tt>X(m) / 8779X u(m);</tt>" as follows: 8780</p> 8781 8782<blockquote> 8783post: <tt><del>u.size() == 0</del><ins>u.empty() == true</ins>, 8784get_allocator() == m</tt> 8785</blockquote> 8786</li> 8787</ol> 8788</li> 8789 8790<li> 8791<p> 8792In 23.2.3 [sequence.reqmts] change Table 83 -- Sequence container requirements as indicated: 8793</p> 8794 8795<ol type="a"> 8796<li> 8797<p> 8798Change the text in the Assertion/note column in the row for "<tt>X(n, 8799t) / X a(n, t)</tt>" as follows: 8800</p> 8801 8802<blockquote> 8803post: <tt><del>size()</del><ins>distance(begin(), end())</ins> == n [..]</tt> 8804</blockquote> 8805</li> 8806 8807<li> 8808<p> 8809Change the text in the Assertion/note column in the row for "<tt>X(i, 8810j) / X a(i, j)</tt>" as follows: 8811</p> 8812 8813<blockquote> 8814[..] post: <del><tt>size() ==</tt> distance between <tt>i</tt> and 8815<tt>j</tt></del><ins><tt>distance(begin(), end()) == distance(i, j)</tt></ins> [..] 8816</blockquote> 8817</li> 8818 8819<li> 8820<p> 8821Change the text in the Assertion/note column in the row for 8822"<tt>a.clear()</tt>" as follows: 8823</p> 8824<blockquote> 8825<tt><ins>a.</ins>erase(<ins>a.</ins>begin(), <ins>a.</ins>end())</tt> post: 8826<tt><del>size() == 0</del><ins>a.empty() == true</ins></tt> 8827</blockquote> 8828</li> 8829</ol> 8830</li> 8831 8832<li> 8833<p> 8834In 23.2.4 [associative.reqmts] change Table 85 -- Associative container requirements as indicated: 8835</p> 8836 8837<p><i>[ 8838Not every occurrence of <tt>size()</tt> was replaced, because all current 8839associative containers 8840have a <tt>size</tt>. The following changes ensure consistency regarding the 8841semantics of "<tt>erase</tt>" 8842for all tables and adds some missing objects 8843]</i></p> 8844 8845 8846<ol type="a"> 8847<li> 8848<p> 8849Change the text in the Complexity column in the row for 8850"<tt>a.insert(i, j)</tt>" as follows: 8851</p> 8852<blockquote> 8853<tt>N log(<ins>a.</ins>size() + N)</tt> <del>(<tt>N</tt> is the distance from <tt>i</tt> to 8854<tt>j</tt>)</del><ins> where <tt>N == distance(i, j)</tt></ins> 8855</blockquote> 8856</li> 8857 8858<li> 8859<p> 8860Change the text in the Complexity column in the row for 8861"<tt>a.erase(k)</tt>" as follows: 8862</p> 8863<blockquote> 8864<tt>log(<ins>a.</ins>size()) + <ins>a.</ins>count(k)</tt> 8865</blockquote> 8866</li> 8867 8868<li> 8869<p> 8870Change the text in the Complexity column in the row for 8871"<tt>a.erase(q1, q2)</tt>" as follows: 8872</p> 8873 8874<blockquote> 8875<tt>log(<ins>a.</ins>size()) + N</tt> where <tt>N</tt> <del>is the distance from <tt>q1</tt> 8876to <tt>q2</tt></del> 8877 <ins><tt>== distance(q1, q2)</tt></ins>. 8878</blockquote> 8879</li> 8880 8881<li> 8882<p> 8883Change the text in the Assertion/note column in the row for 8884"<tt>a.clear()</tt>" as follows: 8885</p> 8886 8887<blockquote> 8888<tt><ins>a.</ins>erase(a.begin(),a.end())</tt> post: <tt><del>size() == 88890</del><ins>a.empty() == true</ins></tt> 8890</blockquote> 8891</li> 8892 8893<li> 8894<p> 8895Change the text in the Complexity column in the row for "<tt>a.clear()</tt>" 8896as follows: 8897</p> 8898 8899<blockquote> 8900linear in <tt><ins>a.</ins>size()</tt> 8901</blockquote> 8902</li> 8903 8904<li> 8905<p> 8906Change the text in the Complexity column in the row for 8907"<tt>a.count(k)</tt>" as follows: 8908</p> 8909 8910<blockquote> 8911<tt>log(<ins>a.</ins>size()) + <ins>a.</ins>count(k)</tt> 8912</blockquote> 8913</li> 8914</ol> 8915</li> 8916 8917<li> 8918<p> 8919In 23.2.5 [unord.req] change Table 87 -- Unordered associative container requirements as indicated: 8920</p> 8921<p><i>[ 8922The same rational as for Table 85 applies here 8923]</i></p> 8924 8925 8926<ol type="a"> 8927<li> 8928<p> 8929Change the text in the Assertion/note column in the row for 8930"<tt>a.clear()</tt>" as follows: 8931</p> 8932 8933<blockquote> 8934[..] Post: <tt>a.<del>size() == 0</del><ins>empty() == true</ins></tt> 8935</blockquote> 8936</li> 8937</ol> 8938</li> 8939</ol> 8940 8941 8942</blockquote> 8943 8944 8945 8946 8947 8948<hr> 8949<h3><a name="865"></a>865. More algorithms that throw away information</h3> 8950<p><b>Section:</b> 25.3.6 [alg.fill], 25.3.7 [alg.generate] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 8951 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2008-07-13 <b>Last modified:</b> 2009-10-23</p> 8952<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 8953<p><b>Discussion:</b></p> 8954<p> 8955In regard to library defect <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#488">488</a> I found some more algorithms which 8956unnecessarily throw away information. These are typically algorithms, 8957which sequentially write into an <tt>OutputIterator</tt>, but do not return the 8958final value of this output iterator. These cases are: 8959</p> 8960 8961<ol> 8962<li> 8963<pre>template<class OutputIterator, class Size, class T> 8964void fill_n(OutputIterator first, Size n, const T& value);</pre></li> 8965 8966<li> 8967<pre>template<class OutputIterator, class Size, class Generator> 8968void generate_n(OutputIterator first, Size n, Generator gen);</pre></li> 8969</ol> 8970<p> 8971In both cases the minimum requirements on the iterator are 8972<tt>OutputIterator</tt>, which means according to the requirements of 897324.2.2 [output.iterators]/2 that only single-pass iterations are guaranteed. 8974So, if users of <tt>fill_n</tt> and <tt>generate_n</tt> have *only* an <tt>OutputIterator</tt> 8975available, they have no chance to continue pushing further values 8976into it, which seems to be a severe limitation to me. 8977</p> 8978 8979<p><i>[ 8980Post Summit Daniel "conceptualized" the wording. 8981]</i></p> 8982 8983 8984<p><i>[ 8985Batavia (2009-05): 8986]</i></p> 8987 8988<blockquote> 8989<p> 8990Alisdair likes the idea, but has concerns about the specific wording 8991about the returns clauses. 8992</p> 8993<p> 8994Alan notes this is a feature request. 8995</p> 8996<p> 8997Bill notes we have made similar changes to other algorithms. 8998</p> 8999<p> 9000Move to Open. 9001</p> 9002</blockquote> 9003 9004<p><i>[ 90052009-07 Frankfurt 9006]</i></p> 9007 9008 9009<blockquote> 9010We have a consensus for moving forward on this issue, but Daniel needs 9011to deconceptify it. 9012</blockquote> 9013 9014<p><i>[ 90152009-07-25 Daniel provided non-concepts wording. 9016]</i></p> 9017 9018 9019<p><i>[ 90202009-10 Santa Cruz: 9021]</i></p> 9022 9023 9024<blockquote> 9025Moved to Ready. 9026</blockquote> 9027 9028 9029 9030<p><b>Proposed resolution:</b></p> 9031 9032<ol> 9033<li> 9034<p> 9035Replace the current declaration of <tt>fill_n</tt> in 25 [algorithms]/2, header 9036<tt><algorithm></tt> synopsis and in 25.3.6 [alg.fill] by 9037</p> 9038 9039<blockquote><pre>template<class OutputIterator, class Size, class T> 9040 <del>void</del><ins>OutputIterator</ins> fill_n(OutputIterator first, Size n, const T& value); 9041</pre></blockquote> 9042 9043<p> 9044Just after the effects clause add a new returns clause saying: 9045</p> 9046 9047<blockquote> 9048<ins><i>Returns:</i> For <tt>fill_n</tt> and positive <tt>n</tt>, returns <tt>first + n</tt>. Otherwise 9049returns <tt>first</tt> for <tt>fill_n</tt>.</ins> 9050</blockquote> 9051</li> 9052 9053<li> 9054<p> 9055Replace the current declaration of <tt>generate_n</tt> in 25 [algorithms]/2, 9056header <tt><algorithm></tt> synopsis and in 25.3.7 [alg.generate] by 9057</p> 9058 9059<blockquote><pre>template<class OutputIterator, class Size, class Generator> 9060 <del>void</del><ins>OutputIterator</ins> generate_n(OutputIterator first, Size n, Generator gen); 9061</pre></blockquote> 9062 9063<p> 9064Just after the effects clause add a new returns clause saying: 9065</p> 9066 9067<blockquote> 9068<ins>For <tt>generate_n</tt> and positive <tt>n</tt>, returns <tt>first + n</tt>. Otherwise 9069returns <tt>first</tt> for <tt>generate_n</tt>.</ins> 9070</blockquote> 9071</li> 9072</ol> 9073 9074 9075 9076 9077 9078 9079 9080<hr> 9081<h3><a name="868"></a>868. default construction and value-initialization</h3> 9082<p><b>Section:</b> 23 [containers] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 9083 <b>Submitter:</b> Alberto Ganesh Barbati <b>Opened:</b> 2008-07-22 <b>Last modified:</b> 2009-10-20</p> 9084<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#containers">active issues</a> in [containers].</p> 9085<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#containers">issues</a> in [containers].</p> 9086<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 9087<p><b>Discussion:</b></p> 9088<p> 9089The term "default constructed" is often used in wording that predates 9090the introduction of the concept of value-initialization. In a few such 9091places the concept of value-initialization is more correct than the 9092current wording (for example when the type involved can be a built-in) 9093so a replacement is in order. Two of such places are already covered by 9094issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#867">867</a>. This issue deliberately addresses the hopefully 9095non-controversial changes in the attempt of being approved more quickly. 9096A few other occurrences (for example in <tt>std::tuple</tt>, 9097<tt>std::reverse_iterator</tt> and <tt>std::move_iterator</tt>) are left to separate 9098issues. For <tt>std::reverse_iterator</tt>, see also issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#408">408</a>. This issue is 9099related with issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#724">724</a>. 9100</p> 9101 9102<p><i>[ 9103San Francisco: 9104]</i></p> 9105 9106 9107<blockquote> 9108<p> 9109The list provided in the proposed resolution is not complete. James 9110Dennett will review the library and provide a complete list and will 9111double-check the vocabulary. 9112</p> 9113<p> 9114This issue relates to Issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#886">886</a> tuple construction 9115</p> 9116</blockquote> 9117 9118<p><i>[ 91192009-07 Frankfurt 9120]</i></p> 9121 9122 9123<blockquote> 9124<p> 9125The proposed resolution is incomplete. 9126</p> 9127<p> 9128Move to Tentatively NAD Future. Howard will contact Ganesh for wording. 9129If wording is forthcoming, Howard will move it back to Review. 9130</p> 9131</blockquote> 9132 9133<p><i>[ 91342009-07-18 Ganesh updated the proposed wording. 9135]</i></p> 9136 9137 9138<blockquote> 9139<p> 9140Howard: Moved back to Review. Note that 20.2.1 [utility.arg.requirements] 9141refers to a section that is not in the current working paper, but does refer to 9142a section that we expect to reappear after the de-concepts merge. This was a 9143point of confusion we did not recognize when we reviewed this issue in Frankfurt. 9144</p> 9145<p> 9146Howard: Ganesh also includes a survey of places in the WP surveyed for changes 9147of this nature and purposefully <em>not</em> treated: 9148</p> 9149 9150<blockquote> 9151<p> 9152Places where changes are <u>not</u> being 9153proposed 9154</p> 9155<p> 9156In the following paragraphs, we are not proposing changes because 9157it's not clear whether we actually prefer value-initialization over 9158default-initialization (now partially covered by <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1012">1012</a>): 9159</p> 9160<ul> 9161 <li><p>20.8.14.2.1 [unique.ptr.single.ctor] para 3 e 7</p></li> 9162 <li><p>24.5.1.3.1 [reverse.iter.cons] para 1</p></li> 9163 <li><p>24.5.3.3.1 [move.iter.op.const] para 1</p></li> 9164</ul> 9165<p>In the following paragraphs, the expression "default 9166constructed" need not be changed, because the relevant type does 9167not depend on a template parameter and has a user-provided 9168constructor:</p> 9169<ul> 9170 <li><p> [func.referenceclosure.invoke] para 12, type: 9171 reference_closure</p></li> 9172 <li><p>30.3.1.2 [thread.thread.constr] para 30, type: thread</p></li> 9173 <li><p>30.3.1.5 [thread.thread.member] para 52, type: thread_id</p></li> 9174 <li><p>30.3.2 [thread.thread.this], para 1, type: thread_id</p></li> 9175</ul> 9176</blockquote> 9177 9178</blockquote> 9179 9180<p><i>[ 91812009-08-18 Daniel adds: 9182]</i></p> 9183 9184 9185<blockquote> 9186<p> 9187I have no objections against the currently suggested changes, but I 9188also cross-checked 9189with the list regarding intentionally excluded changes, and from this 9190I miss the discussion 9191of 9192</p> 9193 9194<ol> 9195<li> 9196<p> 919721.4.1 [string.require]/2: 9198</p> 9199 9200<blockquote> 9201"[..] The <tt>Allocator</tt> object used shall be a copy of the <tt>Allocator></tt> 9202object passed to the <tt>basic_string</tt> object's 9203constructor or, if the constructor does not take an <tt>Allocator</tt> 9204argument, a copy of a default-constructed 9205<tt>Allocator</tt> object." 9206</blockquote> 9207</li> 9208 9209<li> 9210<p> 9211<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2723.pdf">N2723</a>, 9212X [rand.req.eng], Table 109, expression "<tt>T()</tt>": 9213</p> 9214<blockquote> 9215Pre-/post-condition: "Creates an engine with the same initial state as 9216all other default-constructed engines of type <tt>X</tt>." 9217</blockquote> 9218 9219<p> 9220as well as in 26.5.5 [rand.predef]/1-9 (<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2914.pdf">N2914</a>), 26.5.7.1 [rand.util.seedseq]/3, 27.7.1.1.1 [istream.cons]/3, 27.7.2.2 [ostream.cons]/9 (<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2914.pdf">N2914</a>), 28.13 [re.grammar]/2, 30.3.1.4 [thread.thread.assign]/1 (<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2914.pdf">N2914</a>), 9221</p> 9222<p><i>[ 9223Candidates for the "the expression "default constructed" need not be 9224changed" list 9225]</i></p> 9226 9227 9228<p> 9229I'm fine, if these would be added to the intentionally exclusion list, 9230but mentioning them makes it 9231easier for other potential reviewers to decide on the relevance or 9232not-relevance of them for this issue. 9233</p> 9234</li> 9235 9236<li> 9237<p> 9238I suggest to remove the reference of [func.referenceclosure.invoke] 9239in the "it's not clear" list, because 9240this component does no longer exist. 9241</p> 9242</li> 9243 9244<li> 9245<p> 9246I also suggest to add a short comment that all paragraphs in the 9247resolution whether they refer to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2723.pdf">N2723</a> or to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2914.pdf">N2914</a> numbering, because e.g. "Change 23.3.2.1 [deque.cons] para 5" is an <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2723.pdf">N2723</a> coordinate, while "Change 23.3.2.2 [deque.capacity] para 1" is an <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2914.pdf">N2914</a> coordinate. Even better would be to use one default document 9248for the numbering (probably <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2914.pdf">N2914</a>) and mention special cases (e.g. "Change 20.2.1 [utility.arg.requirements] para 2" as referring to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2723.pdf">N2723</a> numbering). 9249</p> 9250</li> 9251</ol> 9252 9253</blockquote> 9254 9255<p><i>[ 92562009-08-18 Alisdair adds: 9257]</i></p> 9258 9259 9260<blockquote> 9261<p> 9262I strongly believe the term "default constructed" should not appear in 9263the library clauses unless we very clearly define a meaning for it, and 9264I am not sure what that would be. 9265</p> 9266 9267<p> 9268In those cases where we do not want to replace "default constructed" 9269with "vale initialized" we should be using "default initialized". If we 9270have a term that could mean either, we reduce portability of programs. 9271</p> 9272 9273<p> 9274I have not done an exhaustive review to clarify if that is a vendor 9275freedom we have reason to support (e.g. value-init in debug, 9276default-init in release) so I may yet be convinced that LWG has reason 9277to define this new term of art, but generally C++ initialization is 9278confusing enough without supporting further ill-defined terms. 9279</p> 9280</blockquote> 9281 9282<p><i>[ 92832009-10 Santa Cruz: 9284]</i></p> 9285 9286 9287<blockquote> 9288Move to Ready. 9289</blockquote> 9290 9291 9292 9293<p><b>Proposed resolution:</b></p> 9294<p> 9295Change 20.2.1 [utility.arg.requirements] para 2: 9296</p> 9297 9298<blockquote> 9299In general, a default constructor is 9300not required. Certain container class member function signatures 9301specify <del>the default constructor</del><ins>T()</ins> 9302as a default argument. T() shall be a well-defined expression (8.5) 9303if one of those signatures is called using the default argument 9304(8.3.6). 9305</blockquote> 9306 9307<p> 9308Change 23.3.2.1 [deque.cons] para 5: 9309</p> 9310 9311<blockquote> 9312<i>Effects:</i> Constructs a deque with n 9313<del>default constructed</del><ins>value-initialized</ins> 9314elements. 9315</blockquote> 9316 9317<p> 9318Change 23.3.2.2 [deque.capacity] para 1: 9319</p> 9320 9321<blockquote> 9322<i>Effects:</i> If sz < size(), equivalent 9323to erase(begin() + sz, end());. If size() < sz, appends sz - 9324size() <del>default 9325constructed</del><ins>value-initialized</ins> 9326elements to the sequence. 9327</blockquote> 9328 9329<p> 9330Change 23.3.3.1 [forwardlist.cons] para 5: 9331</p> 9332 9333<blockquote> 9334<i>Effects:</i> Constructs a forward_list object with n <del>default 9335constructed</del><ins>value-initialized</ins> 9336elements. 9337</blockquote> 9338 9339<p> 9340Change 23.3.3.4 [forwardlist.modifiers] para 21: 9341</p> 9342 9343<blockquote> 9344<i>Effects:</i> [...] For the first signature 9345the inserted elements are <del>default 9346constructed</del><ins>value-initialized</ins>, 9347and for the second signature they are copies of c. 9348</blockquote> 9349 9350<p> 9351Change 23.3.4.1 [list.cons] para 5: 9352</p> 9353 9354<blockquote> 9355<i>Effects:</i> Constructs a list with n <del>default 9356constructed</del><ins>value-initialized</ins> 9357elements. 9358</blockquote> 9359 9360<p> 9361Change 23.3.4.2 [list.capacity] para 15: 9362</p> 9363 9364<blockquote> 9365<i>Effects:</i> If sz < size(), equivalent 9366to list<T>::iterator it = begin(); advance(it, sz); erase(it, 9367end());. If size() < sz, appends sz - size() <del>default 9368constructed</del><ins>value-initialized</ins> 9369elements to the sequence. 9370</blockquote> 9371 9372<p> 9373Change 23.3.6.1 [vector.cons] para 3: 9374</p> 9375 9376<blockquote> 9377<i>Effects:</i> Constructs a vector with n 9378<del>default constructed</del><ins>value-initialized</ins> 9379elements. 9380</blockquote> 9381 9382<p> 9383Change 23.3.6.2 [vector.capacity] para 24: 9384</p> 9385 9386<blockquote> 9387<i>Effects:</i> If sz < size(), equivalent 9388to erase(begin() + sz, end());. If size() < sz, appends sz - 9389size() <del>default 9390constructed</del><ins>value-initialized</ins> 9391elements to the sequence. 9392</blockquote> 9393 9394 9395 9396 9397 9398 9399<hr> 9400<h3><a name="870"></a>870. Do unordered containers not support function pointers for predicate/hasher?</h3> 9401<p><b>Section:</b> 23.2.5 [unord.req] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 9402 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2008-08-17 <b>Last modified:</b> 2009-10-20</p> 9403<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#unord.req">active issues</a> in [unord.req].</p> 9404<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#unord.req">issues</a> in [unord.req].</p> 9405<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 9406<p><b>Discussion:</b></p> 9407<p> 9408Good ol' associative containers allow both function pointers and 9409function objects as feasible 9410comparators, as described in 23.2.4 [associative.reqmts]/2: 9411</p> 9412 9413<blockquote> 9414Each associative container is parameterized on <tt>Key</tt> and an ordering 9415relation <tt>Compare</tt> that 9416induces a strict weak ordering (25.3) on elements of Key. [..]. The 9417object of type <tt>Compare</tt> is 9418called the comparison object of a container. This comparison object 9419may be a pointer to 9420function or an object of a type with an appropriate function call operator.[..] 9421</blockquote> 9422 9423<p> 9424The corresponding wording for unordered containers is not so clear, 9425but I read it to disallow 9426function pointers for the hasher and I miss a clear statement for the 9427equality predicate, see 942823.2.5 [unord.req]/3+4+5: 9429</p> 9430 9431<blockquote> 9432<p> 9433Each unordered associative container is parameterized by <tt>Key</tt>, by a 9434function object <tt>Hash</tt> that 9435acts as a hash function for values of type <tt>Key</tt>, and by a binary 9436predicate <tt>Pred</tt> that induces an 9437equivalence relation on values of type <tt>Key</tt>.[..] 9438</p> 9439<p> 9440A hash function is a function object that takes a single argument of 9441type <tt>Key</tt> and returns a 9442value of type <tt>std::size_t</tt>. 9443</p> 9444<p> 9445Two values <tt>k1</tt> and <tt>k2</tt> of type <tt>Key</tt> are considered equal if the 9446container's equality function object 9447returns <tt>true</tt> when passed those values.[..] 9448</p> 9449</blockquote> 9450 9451<p> 9452and table 97 says in the column "assertion...post-condition" for the 9453expression X::hasher: 9454</p> 9455 9456<blockquote> 9457<tt>Hash</tt> shall be a unary function object type such that the expression 9458<tt>hf(k)</tt> has type <tt>std::size_t</tt>. 9459</blockquote> 9460 9461<p> 9462Note that 20.7 [function.objects]/1 defines as "Function objects are 9463objects with an <tt>operator()</tt> defined.[..]" 9464</p> 9465<p> 9466Does this restriction exist by design or is it an oversight? If an 9467oversight, I suggest that to apply 9468the following 9469</p> 9470 9471<p><i>[ 94722009-07-28 Reopened by Alisdair. No longer solved by concepts. 9473]</i></p> 9474 9475 9476<p><i>[ 94772009-10 Santa Cruz: 9478]</i></p> 9479 9480 9481<blockquote> 9482Ask Daniel to provide proposed wording that: makes it explicit that 9483function pointers are function objects at the beginning of 20.7 [function.objects]; fixes the "requirements" for typedefs in 948420.7.5 [refwrap] to instead state that the function objects 9485defined in that clause have these typedefs, but not that these typedefs 9486are requirements on function objects; remove the wording that explicitly 9487calls out that associative container comparators may be function 9488pointers. 9489</blockquote> 9490 9491 9492 9493<p><b>Proposed resolution:</b></p> 9494<p> 9495In 23.2.5 [unord.req]/3, just after the second sentence which is written as 9496</p> 9497 9498<blockquote> 9499Additionally, <tt>unordered_map</tt> and <tt>unordered_multimap</tt> associate an 9500arbitrary mapped type <tt>T</tt> with the <tt>Key</tt>. 9501</blockquote> 9502 9503<p> 9504add one further sentence: 9505</p> 9506 9507<blockquote> 9508Both <tt>Hash</tt> and <tt>Pred</tt> may be pointers to function or objects of a type 9509with an appropriate function call operator. 9510</blockquote> 9511 9512<p> 9513[Note1: Since the detailed requirements for <tt>Pred</tt> and <tt>Hash</tt> are given in 9514p.4 and p.5, it an alternative resolution 9515would be to insert a new paragraph just after p.5, which contains the 9516above proposed sentence] 9517</p> 9518<p> 9519[Note2: I do not propose a change of above quoted element in table 97, 9520because the mis-usage of the 9521notion of "function object" seems already present in the standard at 9522several places, even if it includes 9523function pointers, see e.g. 25 [algorithms]/7. The important point is 9524that in those places a statement is 9525given that the actually used symbol, like "Predicate" applies for 9526function pointers as well] 9527</p> 9528 9529 9530<p><b>Rationale:</b></p> 9531<p><i>[ 9532San Francisco: 9533]</i></p> 9534 9535 9536<blockquote> 9537This is fixed by 9538<a href="" ref="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2776.pdf">N2776</a>. 9539</blockquote> 9540 9541 9542 9543 9544 9545 9546<hr> 9547<h3><a name="871"></a>871. Iota's requirements on T are too strong</h3> 9548<p><b>Section:</b> 26.7.5 [numeric.iota] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 9549 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2008-08-20 <b>Last modified:</b> 2009-10-22</p> 9550<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 9551<p><b>Discussion:</b></p> 9552<p> 9553According to the recent WP 9554<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2691.pdf">N2691</a>, 955526.7.5 [numeric.iota]/1, the requires clause 9556of <tt>std::iota</tt> says: 9557</p> 9558 9559<blockquote> 9560<tt>T</tt> shall meet the requirements of <tt>CopyConstructible</tt> and <tt>Assignable</tt> types, and 9561shall be convertible to <tt>ForwardIterator</tt>'s value type.[..] 9562</blockquote> 9563 9564<p> 9565Neither <tt>CopyConstructible</tt> nor <tt>Assignable</tt> is needed, instead <tt>MoveConstructible</tt> 9566seems to be the correct choice. I guess the current wording resulted as an 9567artifact from comparing it with similar numerical algorithms like <tt>accumulate</tt>. 9568</p> 9569 9570<p> 9571Note: If this function will be conceptualized, the here proposed 9572<tt>MoveConstructible</tt> 9573requirement can be removed, because this is an implied requirement of 9574function arguments, see 9575<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2710.pdf">N2710</a>/[temp.req.impl]/3, last bullet. 9576</p> 9577 9578<p><i>[ 9579post San Francisco: 9580]</i></p> 9581 9582 9583<blockquote> 9584Issue pulled by author prior to review. 9585</blockquote> 9586 9587<p><i>[ 95882009-07-30 Daniel reopened: 9589]</i></p> 9590 9591 9592<blockquote> 9593with the absence of concepts, this issue (closed) is valid again and I 9594suggest to reopen it. 9595I also revised by proposed resolution based on N2723 wording: 9596</blockquote> 9597 9598<p><i>[ 95992009-10 Santa Cruz: 9600]</i></p> 9601 9602 9603<blockquote> 9604Change 'convertible' to 'assignable', Move To Ready. 9605</blockquote> 9606 9607 9608 9609<p><b>Proposed resolution:</b></p> 9610<p> 9611Change the first sentence of 26.7.5 [numeric.iota]/1: 9612</p> 9613 9614<blockquote> 9615<i>Requires:</i> <tt>T</tt> shall <del>meet the requirements of <tt>CopyConstructible</tt> and 9616<tt>Assignable</tt> types, and shall</del> be 9617assignable to <tt>ForwardIterator</tt>'s value type. [..] 9618</blockquote> 9619 9620 9621 9622 9623 9624 9625 9626 9627<hr> 9628<h3><a name="872"></a>872. <tt>move_iterator::operator[]</tt> has wrong return type</h3> 9629<p><b>Section:</b> 24.5.3.3.12 [move.iter.op.index] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 9630 <b>Submitter:</b> Doug Gregor <b>Opened:</b> 2008-08-21 <b>Last modified:</b> 2009-10-23</p> 9631<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 9632<p><b>Discussion:</b></p> 9633<p> 9634<tt>move_iterator</tt>'s <tt>operator[]</tt> is declared as: 9635</p> 9636 9637<blockquote><pre>reference operator[](difference_type n) const; 9638</pre></blockquote> 9639 9640<p> 9641This has the same problem that <tt>reverse_iterator</tt>'s <tt>operator[]</tt> used to 9642have: if the underlying iterator's <tt>operator[]</tt> returns a proxy, the 9643implicit conversion to <tt>value_type&&</tt> could end up referencing a temporary 9644that has already been destroyed. This is essentially the same issue that 9645we dealt with for <tt>reverse_iterator</tt> in DR <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#386">386</a>. 9646</p> 9647 9648<p><i>[ 96492009-07-28 Reopened by Alisdair. No longer solved by concepts. 9650]</i></p> 9651 9652 9653<p><i>[ 96542009-08-15 Howard adds: 9655]</i></p> 9656 9657 9658<blockquote> 9659I recommend closing this as a duplicate of <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1051">1051</a> which addresses 9660this issue for both <tt>move_iterator</tt> and <tt>reverse_iterator</tt>. 9661</blockquote> 9662 9663<p><i>[ 96642009-10 Santa Cruz: 9665]</i></p> 9666 9667 9668<blockquote> 9669Move to Ready. Note that if <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1051">1051</a> is reopened, it may yield a 9670better resolution, but <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1051">1051</a> is currently marked NAD. 9671</blockquote> 9672 9673 9674 9675<p><b>Proposed resolution:</b></p> 9676<p> 9677In 24.5.3.1 [move.iterator] and 24.5.3.3.12 [move.iter.op.index], change the declaration of 9678<tt>move_iterator</tt>'s <tt>operator[]</tt> to: 9679</p> 9680 9681<blockquote><pre><del>reference</del> <ins><i>unspecified</i></ins> operator[](difference_type n) const; 9682</pre></blockquote> 9683 9684 9685 9686<p><b>Rationale:</b></p> 9687<p><i>[ 9688San Francisco: 9689]</i></p> 9690 9691 9692<blockquote> 9693NAD Editorial, see 9694<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2777.pdf">N2777</a>. 9695</blockquote> 9696 9697 9698 9699 9700<hr> 9701<h3><a name="885"></a>885. pair assignment</h3> 9702<p><b>Section:</b> 20.3.4 [pairs] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 9703 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2008-09-15 <b>Last modified:</b> 2009-07-17</p> 9704<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#pairs">active issues</a> in [pairs].</p> 9705<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#pairs">issues</a> in [pairs].</p> 9706<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 9707<p><b>Discussion:</b></p> 9708<blockquote><pre>20.2.3 pairs 9709Missing assignemnt operator: 9710template<class U , class V> 9711 requires CopyAssignable<T1, U> && CopyAssignable<T2, V> 9712 pair& operator=(pair<U , V> const & p ); 9713</pre></blockquote> 9714 9715<p> 9716Well, that's interesting. This assignment operator isn't in the 9717current working paper, either. Perhaps we deemed it acceptable to 9718build a temporary of type <tt>pair</tt> from <tt>pair<U, V></tt>, then move-assign 9719from that temporary? 9720</p> 9721<p> 9722It sounds more like an issue waiting to be opened, unless you want to plug 9723it now. As written we risk moving from lvalues. 9724</p> 9725 9726<p><i>[ 9727San Francisco: 9728]</i></p> 9729 9730 9731<blockquote> 9732<p> 9733Would be NAD if better ctors fixed it. 9734</p> 9735<p> 9736Related to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#811">811</a>. 9737</p> 9738</blockquote> 9739 9740<p><i>[ 9741post San Francisco: 9742]</i></p> 9743 9744 9745<blockquote> 9746Possibly NAD Editorial, solved by 9747<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2770.pdf">N2770</a>. 9748</blockquote> 9749 9750<p><i>[ 97512009-05-25 Alisdair adds: 9752]</i></p> 9753 9754 9755<blockquote> 9756Issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#885">885</a> was something I reported while reviewing the library concepts 9757documents ahead of San Francisco. The missing operator was added as part of 9758the paper adopted at that meeting 9759(<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2770.pdf">N2770</a>) 9760and I can confirm this operator is 9761present in the current working paper. I recommend NAD. 9762</blockquote> 9763 9764<p><i>[ 97652009-07 Frankfurt 9766]</i></p> 9767 9768 9769<blockquote> 9770We agree with the intent, but we need to wait for the dust to settle on concepts. 9771</blockquote> 9772 9773 9774 9775<p><b>Proposed resolution:</b></p> 9776<p> 9777</p> 9778 9779 9780 9781 9782 9783<hr> 9784<h3><a name="887"></a>887. issue with condition::wait_...</h3> 9785<p><b>Section:</b> 30.5.1 [thread.condition.condvar] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 9786 <b>Submitter:</b> Lawrence Crowl <b>Opened:</b> 2008-09-15 <b>Last modified:</b> 2009-10-26</p> 9787<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#thread.condition.condvar">active issues</a> in [thread.condition.condvar].</p> 9788<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#thread.condition.condvar">issues</a> in [thread.condition.condvar].</p> 9789<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 9790<p><b>Discussion:</b></p> 9791<p> 9792The Posix/C++ working group has identified an inconsistency between 9793Posix and the C++ working draft in that Posix requires the clock to be 9794identified at creation, whereas C++ permits identifying the clock at the 9795call to wait. The latter cannot be implemented with the former. 9796</p> 9797 9798<p><i>[ 9799San Francisco: 9800]</i></p> 9801 9802 9803<blockquote> 9804<p> 9805Howard recommends NAD with the following explanation: 9806</p> 9807 9808<p> 9809The intent of the current wording is for the <tt>condtion_variable::wait_until</tt> 9810be able to handle user-defined clocks as well as clocks the system knows about. 9811This can be done by providing overloads for the known clocks, and another 9812overload for unknown clocks which synchs to a known clock before waiting. 9813For example: 9814</p> 9815 9816<blockquote><pre>template <class Duration> 9817bool 9818condition_variable::wait_until(unique_lock<mutex>& lock, 9819 const chrono::time_point<chrono::system_clock, Duration>& abs_time) 9820{ 9821 using namespace chrono; 9822 nanoseconds d = __round_up<nanoseconds>(abs_time.time_since_epoch()); 9823 __do_timed_wait(lock.mutex()->native_handle(), time_point<system_clock, nanoseconds>(d)); 9824 return system_clock::now() < abs_time; 9825} 9826 9827template <class Clock, class Duration> 9828bool 9829condition_variable::wait_until(unique_lock<mutex>& lock, 9830 const chrono::time_point<Clock, Duration>& abs_time) 9831{ 9832 using namespace chrono; 9833 system_clock::time_point s_entry = system_clock::now(); 9834 typename Clock::time_point c_entry = Clock::now(); 9835 nanoseconds dn = __round_up<nanoseconds>(abs_time.time_since_epoch() - 9836 c_entry.time_since_epoch()); 9837 __do_timed_wait(lock.mutex()->native_handle(), s_entry + dn); 9838 return Clock::now() < abs_time; 9839} 9840</pre></blockquote> 9841 9842<p> 9843In the above example, <tt>system_clock</tt> is the only clock which the underlying 9844condition variable knows how to deal with. One overload just passes that clock 9845through. The second overload (approximately) converts the unknown clock into 9846a <tt>system_clock time_point</tt> prior to passing it down to the native 9847condition variable. 9848</p> 9849 9850<p> 9851On Posix systems vendors are free to add implementation defined constructors which 9852take a clock. That clock can be stored in the condition_variable, and converted 9853to (or not as necessary) as shown above. 9854</p> 9855 9856<p> 9857If an implementation defined constructor takes a clock (for example), then part 9858of the semantics for that implementation defined ctor might include that a 9859<tt>wait_until</tt> using a clock other than the one constructed with results 9860in an error (exceptional condition) instead of a conversion to the stored clock. 9861Such a design is up to the vendor as once an implementation defined ctor is used, 9862the vendor is free to specifiy the behavior of waits and/or notifies however 9863he pleases (when the cv is constructed in an implementation defined manner). 9864</p> 9865</blockquote> 9866 9867<p><i>[ 9868Post Summit: 9869]</i></p> 9870 9871 9872<blockquote> 9873<p> 9874"POSIX people will review the proposed NAD resolution at their upcoming NY 9875meeting. 9876</p> 9877 9878<p> 9879See the minutes at: <a href="http://wiki.dinkumware.com/twiki/bin/view/Posix/POSIX-CppBindingWorkingGroupNewYork2009">http://wiki.dinkumware.com/twiki/bin/view/Posix/POSIX-CppBindingWorkingGroupNewYork2009</a>. 9880</p> 9881</blockquote> 9882 9883<p><i>[ 98842009-07 Frankfurt 9885]</i></p> 9886 9887 9888<blockquote> 9889Move to NAD. 9890</blockquote> 9891 9892<p><i>[ 98932009-07-18 Detlef reopens the issue: 9894]</i></p> 9895 9896 9897<blockquote> 9898<p> 9899On Friday afternoon in Frankfurt is was decided that 887 is NAD. 9900This decision was mainly based on a sample implementation presented 9901by Howard that implemented one clock on top of another. 9902Unfortunately this implementation doesn't work for the probably most 9903important case where a system has a monotonic clock and a real-time 9904clock (or "wall time" clock): 9905</p> 9906<p> 9907If the underlying "system_clock" is a monotonic clock, and 9908the program waits on the real-time clock, and the real-time clock 9909is set forward, the wait will unblock too late. 9910</p> 9911 9912<p> 9913If the underlying "system_clock" is a real-time clock, and the 9914program waits on the monotonic clock, and the real-time clock 9915is set back, the wait again will unblock too late. 9916</p> 9917 9918<p> 9919Sorry that I didn't remember this on Friday, but it was Friday 9920afternoon after a busy week... 9921</p> 9922 9923<p> 9924So as the decision was made on a wrong asumption, I propose to re-open 9925the issue. 9926</p> 9927</blockquote> 9928 9929<p><i>[ 99302009-07-26 Howard adds: 9931]</i></p> 9932 9933 9934<blockquote> 9935<p> 9936Detlef correctly argues that <tt>condition_variable::wait_until</tt> could 9937return "too late" in the context of clocks being adjusted during the wait. I agree 9938with his logic. But I disagree that this makes this interface unimplementable 9939on POSIX. 9940</p> 9941 9942<p> 9943The POSIX spec also does not guarantee that <tt>pthread_cond_timedwait</tt> does 9944not return "too late" when clocks are readjusted during the wait. Indeed, the 9945POSIX specification lacks any requirements at all concerning how soon 9946<tt>pthread_cond_timedwait</tt> returns after a time out. This is evidently a 9947QOI issue by the POSIX standard. Here is a quote of the most relevant normative 9948text concerning <tt>pthread_cond_timedwait</tt> found 9949<a href="http://www.unix.org/single_unix_specification/">here</a>. 9950</p> 9951 9952<blockquote> 9953The <tt>pthread_cond_timedwait()</tt> function shall be equivalent to 9954<tt>pthread_cond_wait()</tt>, except that an error is returned if the absolute 9955time specified by <tt>abstime</tt> passes (that is, system time equals or exceeds 9956<tt>abstime</tt>) before the condition <tt>cond</tt> is signaled or broadcasted, or if the 9957absolute time specified by <tt>abstime</tt> has already been passed at the time 9958of the call. 9959</blockquote> 9960 9961<p> 9962I.e. the POSIX specification speaks of the error code returned in case of a time 9963out, but not on the timeliness of that return. 9964</p> 9965 9966<p> 9967Might this simply be an oversight, or minor defect in the POSIX specification? 9968</p> 9969 9970<p> 9971I do not believe so. This same section goes on to say in <em>non-normative</em> 9972text: 9973</p> 9974 9975<blockquote> 9976For cases when the system clock is advanced discontinuously by an 9977operator, it is expected that implementations process any timed wait 9978expiring at an intervening time as if that time had actually occurred. 9979</blockquote> 9980 9981<p> 9982Here is non-normative wording encouraging the implementation to ignore an advancing 9983underlying clock and subsequently causing an early (spurious) return. There is 9984no wording at all which addresses Detlef's example of a "late return". With 9985<tt>pthread_cond_timedwait</tt> this would be caused by setting the system clock 9986backwards. It seems reasonable to assume, based on the wording that is already 9987in the POSIX spec, that again, the discontinuously changed clock would be ignored 9988by <tt>pthread_cond_timedwait</tt>. 9989</p> 9990 9991<p> 9992A noteworthy difference between <tt>pthread_cond_timedwait</tt> and 9993<tt>condition_variable::wait_until</tt> is that the POSIX spec appears to 9994say that <tt>ETIMEDOUT</tt> should be returned if <tt>pthread_cond_timedwait</tt> 9995returns because of timeout signal, whether or not the system clock was discontinuously 9996advanced during the wait. In contrast <tt>condition_variable::wait_until</tt> 9997always returns: 9998</p> 9999 10000<blockquote><pre><tt>Clock::now() < abs_time</tt> 10001</pre></blockquote> 10002 10003<p> 10004That is, the C++ spec requires that the clock be rechecked (detecting discontinuous 10005adjustments during the wait) at the time of return. <tt>condition_variable::wait_until</tt> 10006may indeed return early or late. But regardless it will return a value 10007reflecting timeout status at the time of return (even if clocks have been adjusted). 10008Of course the clock may be adjusted after the return value is computed but before the client has 10009a chance to read the result of the return. Thus there are no iron-clad guarantees 10010here. 10011</p> 10012 10013<p> 10014<tt>condition_variable::wait_until</tt> (and <tt>pthread_cond_timedwait</tt>) 10015is little more than a convenience function for making sure 10016<tt>condition_variable::wait</tt> doesn't hang for an unreasonable amount of 10017time (where the client gets to define "unreasonable"). I do not think it 10018is in anyone's interest to try to make it into anything more than that. 10019</p> 10020 10021<p> 10022I maintain that this is a useful and flexible specification in the spirit of 10023C++, and is implementable on POSIX. The implementation technique described above 10024is a reasonable approach. There may also be higher quality approaches. This 10025specification, like the POSIX specification, gives a wide latitude for QOI. 10026</p> 10027 10028<p> 10029I continue to recommend NAD, but would not object to a clarifying note regarding 10030the behavior of <tt>condition_variable::wait_until</tt>. At the moment, I do 10031not have good wording for such a note, but welcome suggestions. 10032</p> 10033 10034</blockquote> 10035 10036<p><i>[ 100372009-09-30: See <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2969.html">N2969</a>. 10038]</i></p> 10039 10040 10041<p><i>[ 100422009-10 Santa Cruz: 10043]</i></p> 10044 10045 10046<blockquote> 10047The LWG is in favor of Detlef to supply revision which adopts Option 2 from 10048<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2969.html">N2969</a> 10049but is modified by saying that <tt>system_clock</tt> must be available for <tt>wait_until</tt>. 10050</blockquote> 10051 10052 10053 10054<p><b>Proposed resolution:</b></p> 10055<p> 10056</p> 10057 10058 10059 10060 10061 10062<hr> 10063<h3><a name="889"></a>889. thread::id comparisons</h3> 10064<p><b>Section:</b> 30.3.1.1 [thread.thread.id] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 10065 <b>Submitter:</b> Lawrence Crowl <b>Opened:</b> 2008-09-15 <b>Last modified:</b> 2009-10-22</p> 10066<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#thread.thread.id">issues</a> in [thread.thread.id].</p> 10067<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 10068<p><b>Discussion:</b></p> 10069 10070<p><b>Addresses UK 324</b></p> 10071 10072<p> 10073The <tt>thread::id</tt> type supports the full set of comparison operators. This 10074is substantially more than is required for the associative containers that 10075justified them. Please place an issue against the threads library. 10076</p> 10077 10078<p><i>[ 10079San Francisco: 10080]</i></p> 10081 10082 10083<blockquote> 10084<p> 10085Would depend on proposed extension to POSIX, or non-standard extension. 10086What about hash? POSIX discussing op. POSIX not known to be considering 10087support needed for hash, op. 10088</p> 10089<p> 10090Group expresses support for putting ids in both unordered and ordered containers. 10091</p> 10092</blockquote> 10093 10094<p><i>[ 10095post San Francisco: 10096]</i></p> 10097 10098 10099<blockquote> 10100<p> 10101Howard: It turns out the current working paper 10102<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2723.pdf">N2723</a> 10103<i>already has</i> <tt>hash<thread::id></tt> 10104(20.7 [function.objects], 20.7.16 [unord.hash]). We simply 10105overlooked it in the meeting. It is a good thing we voted in favor of it 10106(again). :-) 10107</p> 10108<p> 10109Recommend NAD. 10110</p> 10111 10112</blockquote> 10113 10114<p><i>[ 10115Post Summit: 10116]</i></p> 10117 10118 10119<blockquote> 10120Recommend to close as NAD. For POSIX, see if we need to add a function to 10121convert <tt>pthread_t</tt> to integer. 10122</blockquote> 10123 10124<p><i>[ 10125Post Summit, Alisdair adds: 10126]</i></p> 10127 10128 10129<blockquote> 10130<p> 10131The recommendation for LWG-889/UK-324 is NAD, already specified. 10132</p> 10133<p> 10134It is not clear to me that the specification is complete. 10135</p> 10136<p> 10137In particular, the synopsis of <tt><functional></tt> in 20.7 [function.objects] does not mention <tt>hash< thread::id 10138></tt> nor <tt>hash< error_code ></tt>, although their 10139existence is implied by 20.7.16 [unord.hash], p1. 10140</p> 10141<p> 10142I am fairly uncomfortable putting the declaration for the 10143<tt>thread_id</tt> specialization into <tt><functional></tt> as 10144<tt>id</tt> is a nested class inside <tt>std::thread</tt>, so it implies 10145that <tt><functional></tt> would require the definition of the 10146<tt>thread</tt> class template in order to forward declared 10147<tt>thread::id</tt> and form this specialization. 10148</p> 10149<p> 10150It seems better to me that the dependency goes the other way around 10151(<tt><thread></tt> will more typically make use of 10152<tt><functional></tt> than vice-versa) and the 10153<tt>hash<thread::id></tt> specialization be declared in the 10154<tt><thread></tt> header. 10155</p> 10156<p> 10157I think <tt>hash<error_code></tt> could go into either 10158<tt><system_error></tt> or <tt><functional></tt> and have no 10159immediate preference either way. However, it should clearly appear in 10160the synopsis of one of these two. 10161</p> 10162<p> 10163Recommend moving 889 back to open, and tying in a reference to UK-324. 10164</p> 10165</blockquote> 10166 10167<p><i>[ 10168Batavia (2009-05): 10169]</i></p> 10170 10171<blockquote> 10172Howard observes that <tt>thread::id</tt> need not be a nested class; 10173it could be a <tt>typedef</tt> for a more visible type. 10174</blockquote> 10175 10176<p><i>[ 101772009-05-24 Alisdair adds: 10178]</i></p> 10179 10180<blockquote> 10181I do not believe this is correct. <tt>thread::id</tt> is explicitly documents as a 10182nested class, rather than as an unspecified typedef analogous to an 10183iterator. If the intent is that this is not implemented as a nested class 10184(under the as-if freedoms) then this is a novel form of standardese. 10185</blockquote> 10186 10187<p><i>[ 101882009-07 Frankfurt 10189]</i></p> 10190 10191 10192<blockquote> 10193Decided we want to move hash specialization for thread_id to the thread 10194header. Alisdair to provide wording. 10195</blockquote> 10196 10197<p><i>[ 101982009-07-28 Alisdair provided wording, moved to Review. 10199]</i></p> 10200 10201 10202<p><i>[ 102032009-10 Santa Cruz: 10204]</i></p> 10205 10206 10207<blockquote> 10208Add a strike for <tt>hash<thread::id></tt>. Move to Ready 10209</blockquote> 10210 10211 10212 10213<p><b>Proposed resolution:</b></p> 10214 10215<p> 10216Remove the following prototype from the synopsis in 1021720.7 [function.objects]: 10218</p> 10219 10220<blockquote><pre><del> 10221template <> struct hash<std::thread::id>; 10222</del></pre></blockquote> 10223 10224<p> 10225Add to 30.3 [thread.threads], p1 Header <tt><thread></tt> synopsis: 10226</p> 10227 10228<blockquote><pre><ins>template <class T> struct hash; 10229template <> struct hash<thread::id>;</ins> 10230</pre></blockquote> 10231 10232<p> 10233Add template specialization below class definition in 30.3.1.1 [thread.thread.id] 10234</p> 10235 10236<blockquote><pre><ins>template <> 10237struct hash<thread::id> : public unary_function<thread::id, size_t> { 10238 size_t operator()(thread::id val) const; 10239};</ins> 10240</pre></blockquote> 10241 10242<p> 10243Extend note in p2 30.3.1.1 [thread.thread.id] with second sentence: 10244</p> 10245 10246<blockquote> 10247[<i>Note:</i> Relational operators allow <tt>thread::id</tt> objects to be used 10248as keys in associative containers. 10249<ins><tt>hash</tt> template specialization allow <tt>thread::id</tt> objects to be used as keys 10250in unordered containers.</ins> 10251— <i>end note</i>] 10252</blockquote> 10253 10254<p> 10255Add new paragraph to end of 30.3.1.1 [thread.thread.id] 10256</p> 10257 10258<blockquote><pre><ins>template <> struct hash<thread::id>;</ins> 10259</pre> 10260<blockquote><ins> 10261An explicit specializations of the class template hash (20.7.16 [unord.hash]) 10262shall be provided for the values of type <tt>thread::id</tt> 10263suitable for use as keys in unordered associative containers (23.5 [unord]). 10264</ins></blockquote> 10265</blockquote> 10266 10267 10268 10269 10270 10271<hr> 10272<h3><a name="891"></a>891. std::thread, std::call_once issue</h3> 10273<p><b>Section:</b> 30.3.1.2 [thread.thread.constr], 30.4.5.2 [thread.once.callonce] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 10274 <b>Submitter:</b> Peter Dimov <b>Opened:</b> 2008-09-15 <b>Last modified:</b> 2009-10-24</p> 10275<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#thread.thread.constr">active issues</a> in [thread.thread.constr].</p> 10276<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#thread.thread.constr">issues</a> in [thread.thread.constr].</p> 10277<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 10278<p><b>Discussion:</b></p> 10279<p> 10280I notice that the vararg overloads of <tt>std::thread</tt> and <tt>std::call_once</tt> 10281(N2723 30.3.1.2 [thread.thread.constr] and 30.4.5.2 [thread.once.callonce]) are no longer specified in terms of 10282<tt>std::bind</tt>; instead, some of the <tt>std::bind</tt> wording has been inlined into 10283the specification. 10284</p> 10285<p> 10286There are two problems with this. 10287</p> 10288<p> 10289First, the specification (and implementation) in terms of <tt>std::bind</tt> allows, for example: 10290</p> 10291 10292<blockquote><pre>std::thread th( f, 1, std::bind( g ) ); 10293</pre></blockquote> 10294 10295<p> 10296which executes <tt>f( 1, g() )</tt> in a thread. This can be useful. The 10297"inlined" formulation changes it to execute <tt>f( 1, bind(g) )</tt> in a thread. 10298</p> 10299<p> 10300Second, assuming that we don't want the above, the specification has copied the wording 10301</p> 10302 10303<blockquote> 10304<tt>INVOKE(func, w1, w2, ..., wN)</tt> (20.6.2) shall be a valid 10305expression for some values <tt>w1, w2, ..., wN</tt> 10306</blockquote> 10307 10308<p> 10309but this is not needed since we know that our argument list is args; it should simply be 10310</p> 10311 10312<blockquote> 10313<tt>INVOKE(func, args...)</tt> (20.6.2) shall be a valid expression 10314</blockquote> 10315 10316<p><i>[ 10317Summit: 10318]</i></p> 10319 10320 10321<blockquote> 10322Move to open. 10323</blockquote> 10324 10325<p><i>[ 10326Post Summit Anthony provided proposed wording. 10327]</i></p> 10328 10329 10330<p><i>[ 103312009-07 Frankfurt 10332]</i></p> 10333 10334 10335<blockquote> 10336Leave Open. Await decision for thread variadic constructor. 10337</blockquote> 10338 10339<p><i>[ 103402009-10 Santa Cruz: 10341]</i></p> 10342 10343 10344<blockquote> 10345See proposed wording for <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#929">929</a> for this, for the formulation 10346on how to solve this. <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#929">929</a> modifies the thread constructor to 10347have "pass by value" behavior with pass by reference efficiency through the use 10348of the <tt>decay</tt> trait. This same formula would be useful for <tt>call_once</tt>. 10349</blockquote> 10350 10351 10352 10353<p><b>Proposed resolution:</b></p> 10354<p> 10355Change paragraph 4 of 30.3.1.2 [thread.thread.constr] to: 10356</p> 10357 10358<blockquote> 10359<pre>template <class F> explicit thread(F f); 10360template <class F, class ...Args> thread(F&& f, Args&&... args); 10361</pre> 10362<blockquote> 10363-4- <i>Requires:</i> <tt>F</tt> and each <tt>Ti</tt> in <tt>Args</tt> 10364shall be <tt>CopyConstructible</tt> if an lvalue and otherwise 10365<tt>MoveConstructible</tt>. <tt><i>INVOKE</i>(f, <del>w1, w2, ..., wN</del> <ins>args...</ins>)</tt> 10366(20.6.2) shall be a valid expression<del> for some values <i>w1, w2, ..., 10367wN</i>, where <tt>N == sizeof...(Args)</tt></del>. 10368</blockquote> 10369</blockquote> 10370 10371<p> 10372Change paragraph 1 of 30.4.5.2 [thread.once.callonce] to: 10373</p> 10374 10375<blockquote><pre>template<class Callable, class ...Args> 10376 void call_once(once_flag& flag, Callable func, Args&&... args); 10377</pre> 10378<blockquote> 10379-1- <i>Requires:</i> The template parameters <tt>Callable></tt> and each 10380<tt>Ti</tt> in <tt>Args</tt> shall be <tt>CopyConstructible</tt> if an 10381lvalue and otherwise <tt>MoveConstructible</tt>. <tt><i>INVOKE</i>(func, 10382<del>w1, w2, ..., wN</del> <ins>args...</ins>)</tt> (20.6.2) shall be a 10383valid expression<del> for some values <i>w1, w2, ..., wN</i>, where 10384<tt>N == sizeof...(Args)</tt></del>. 10385</blockquote> 10386</blockquote> 10387 10388 10389 10390 10391 10392<hr> 10393<h3><a name="893"></a>893. std::mutex issue</h3> 10394<p><b>Section:</b> 30.4.1.1 [thread.mutex.class] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 10395 <b>Submitter:</b> Peter Dimov <b>Opened:</b> 2008-09-15 <b>Last modified:</b> 2009-10-22</p> 10396<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#thread.mutex.class">issues</a> in [thread.mutex.class].</p> 10397<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 10398<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#905">905</a></p> 10399<p><b>Discussion:</b></p> 10400<p> 1040130.4.1.1 [thread.mutex.class]/27 (in 10402<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2723.pdf">N2723</a>) 10403says that the behavior is undefined if: 10404</p> 10405<ul> 10406<li>a thread that owns a <tt>mutex</tt> object calls <tt>lock()</tt> or 10407<tt>try_lock()</tt> on that object</li> 10408</ul> 10409<p> 10410I don't believe that this is right. Calling <tt>lock()</tt> or <tt>try_lock()</tt> on a 10411locked <tt>mutex</tt> is well defined in the general case. <tt>try_lock()</tt> is required 10412to fail and return <tt>false</tt>. <tt>lock()</tt> is required to either throw an 10413exception (and is allowed to do so if it detects deadlock) or to block 10414until the <tt>mutex</tt> is free. These general requirements apply regardless of 10415the current owner of the <tt>mutex</tt>; they should apply even if it's owned by 10416the current thread. 10417</p> 10418<p> 10419Making double <tt>lock()</tt> undefined behavior probably can be justified (even 10420though I'd still disagree with the justification), but <tt>try_lock()</tt> on a 10421locked <tt>mutex</tt> must fail. 10422</p> 10423 10424<p><i>[ 10425Summit: 10426]</i></p> 10427 10428<blockquote> 10429<p> 10430Move to open. Proposed resolution: 10431</p> 10432<ul> 10433<li> 10434In 30.4.1 [thread.mutex.requirements] paragraph 12, change the error 10435condition for <tt>resource_deadlock_would_occur</tt> to: "if the implementation 10436detects that a deadlock would occur" 10437</li> 10438<li> 10439Strike 30.4.1.1 [thread.mutex.class] paragraph 3 bullet 2 "a thread that owns a mutex object 10440calls <tt>lock()</tt> or <tt>try_lock()</tt> on that object, or" 10441</li> 10442</ul> 10443</blockquote> 10444 10445<p><i>[ 104462009-07 Frankfurt 10447]</i></p> 10448 10449 10450<blockquote> 10451Move to Review. Alisdair to provide note. 10452</blockquote> 10453 10454<p><i>[ 104552009-07-31 Alisdair provided note. 10456]</i></p> 10457 10458 10459<p><i>[ 104602009-10 Santa Cruz: 10461]</i></p> 10462 10463 10464<blockquote> 10465Moved to Ready. 10466</blockquote> 10467 10468 10469 10470<p><b>Proposed resolution:</b></p> 10471<p> 10472In 30.4.1 [thread.mutex.requirements] paragraph 12 change: 10473</p> 10474 10475<blockquote> 10476<ul> 10477<li>...</li> 10478<li> 10479<tt>resource_deadlock_would_occur</tt> -- if the <del>current thread already owns the mutex and is able 10480to detect it</del> <ins>implementation detects that a deadlock would occur</ins>. 10481</li> 10482<li>...</li> 10483</ul> 10484</blockquote> 10485 10486<p> 10487Strike 30.4.1.1 [thread.mutex.class] paragraph 3 bullet 2: 10488</p> 10489<blockquote> 10490<p> 10491-3- The behavior of a program is undefined if: 10492</p> 10493<ul> 10494<li>...</li> 10495<li> 10496<del>a thread that owns a <tt>mutex</tt> object calls <tt>lock()</tt> or <tt>try_lock()</tt> on that object, or</del> 10497</li> 10498<li>...</li> 10499</ul> 10500</blockquote> 10501 10502<p> 10503Add the following note after p3 30.4.1.1 [thread.mutex.class] 10504</p> 10505 10506<blockquote> 10507[<i>Note:</i> a program may deadlock if the thread that owns a <tt>mutex</tt> 10508object calls <tt>lock()</tt> or <tt>try_lock()</tt> on that object. If the program can 10509detect the deadlock, a <tt>resource_deadlock_would_occur</tt> error condition may 10510be observed. — <i>end note</i>] 10511</blockquote> 10512 10513 10514 10515 10516 10517 10518<hr> 10519<h3><a name="896"></a>896. Library thread safety issue</h3> 10520<p><b>Section:</b> 20.8.15.2 [util.smartptr.shared] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 10521 <b>Submitter:</b> Hans Boehm <b>Opened:</b> 2008-09-16 <b>Last modified:</b> 2009-10-25</p> 10522<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#util.smartptr.shared">issues</a> in [util.smartptr.shared].</p> 10523<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 10524<p><b>Discussion:</b></p> 10525<p> 10526It is unclear whether <tt>shared_ptr</tt> is thread-safe in the sense that 10527multiple threads may simultaneously copy a <tt>shared_ptr</tt>. However this 10528is a critical piece of information for the client, and it has significant 10529impact on usability for many applications. (Detlef Vollman thinks it 10530is currently clear that it is not thread-safe. Hans Boehm thinks 10531it currently requires thread safety, since the <tt>use_count</tt> is not an 10532explicit field, and constructors and assignment take a const reference 10533to an existing <tt>shared_ptr</tt>.) 10534</p> 10535 10536<p> 10537Pro thread-safety: 10538</p> 10539<p> 10540Many multi-threaded usages are impossible. A thread-safe version can 10541be used to destroy an object when the last thread drops it, something 10542that is often required, and for which we have no other easy mechanism. 10543</p> 10544<p> 10545Against thread-safety: 10546</p> 10547<p> 10548The thread-safe version is well-known to be far more expensive, even 10549if used by a single thread. Many applications, including all single-threaded 10550ones, do not care. 10551</p> 10552 10553<p><i>[ 10554San Francisco: 10555]</i></p> 10556 10557 10558<blockquote> 10559<p> 10560Beman: this is a complicated issue, and would like to move this to Open 10561and await comment from Peter Dimov; we need very careful and complete 10562rationale for any decision we make; let's go slow 10563</p> 10564<p> 10565Detlef: I think that <tt>shared_ptr</tt> should not be thread-safe. 10566</p> 10567<p> 10568Hans: When you create a thread with a lambda, it in some cases makes it 10569very difficult for the lambda to reference anything in the heap. It's 10570currently ambiguous as to whether you can use a <tt>shared_ptr</tt> to get at an 10571object. 10572</p> 10573<p> 10574Leave in Open. Detlef will submit an alternative proposed resolution 10575that makes <tt>shared_ptr</tt> explicitly unsafe. 10576</p> 10577<p> 10578A third option is to support both threadsafe and non-safe share_ptrs, 10579and to let the programmer decide which behavior they want. 10580</p> 10581 10582<p> 10583Beman: Peter, do you support the PR? 10584</p> 10585 10586<p> 10587Peter: 10588</p> 10589<blockquote> 10590<p> 10591Yes, I support the proposed resolution, and I certainly oppose any 10592attempts to <tt>make shared_ptr</tt> thread-unsafe. 10593</p> 10594<p> 10595I'd mildly prefer if 10596</p> 10597<blockquote> 10598[<i>Note:</i> This is true in spite of that fact that such functions often 10599modify <tt>use_count()</tt> <i>--end note</i>] 10600</blockquote> 10601<p> 10602is changed to 10603</p> 10604<blockquote> 10605[<i>Note:</i> This is true in spite of that fact that such functions often 10606cause a change in <tt>use_count()</tt> <i>--end note</i>] 10607</blockquote> 10608<p> 10609(or something along these lines) to emphasise that <tt>use_count()</tt> is not, 10610conceptually, a variable, but a return value. 10611</p> 10612</blockquote> 10613 10614</blockquote> 10615 10616<p><i>[ 106172009-07 Frankfurt 10618]</i></p> 10619 10620 10621<blockquote> 10622<p> 10623Vote: Do we want one thread-safe shared pointer or two? If two, one 10624would allow concurrent construction and destruction of shared pointers, 10625and one would not be thread-safe. If one, then it would be thread-safe. 10626</p> 10627<p> 10628No concensus on that vote. 10629</p> 10630<p> 10631Hans to improve wording in consultation with Pete. Leave Open. 10632</p> 10633</blockquote> 10634 10635<p><i>[ 106362009-10 Santa Cruz: 10637]</i></p> 10638 10639 10640<blockquote> 10641Move to Ready. Ask Editor to clear up wording a little when integrating to 10642make it clear that the portion after the first comma only applies for 10643the presence of data races. 10644</blockquote> 10645 10646<p><i>[ 106472009-10-24 Hans adds: 10648]</i></p> 10649 10650 10651<blockquote> 10652<p> 10653I think we need to pull 896 back from ready, unfortunately. My wording 10654doesn't say the right thing. 10655</p> 10656 10657<p> 10658I suspect we really want to say something along the lines of: 10659</p> 10660 10661<blockquote> 10662For purposes of determining the presence of a data race, member 10663functions access and modify only the <tt>shared_ptr</tt> and 10664<tt>weak_ptr</tt> objects themselves and not objects they refer to. 10665Changes in <tt>use_count()</tt> do not reflect modifications that can 10666introduce data races. 10667</blockquote> 10668 10669<p> 10670But I think this needs further discussion by experts to make sure this 10671is right. 10672</p> 10673 10674<p> 10675Detlef and I agree continue to disagree on the resolution, but I think 10676we agree that it would be good to try to expedite this so that it can be 10677in CD2, since it's likely to generate NB comments no matter what we do. 10678And lack of clarity of intent is probably the worst option. I think it 10679would be good to look at this between meetings. 10680</p> 10681</blockquote> 10682 10683 10684 10685<p><b>Proposed resolution:</b></p> 10686<p> 10687Make it explicitly thread-safe, in this weak sense, as I believe was intended: 10688</p> 10689<p> 10690Insert in 20.8.15.2 [util.smartptr.shared], before p5: 10691</p> 10692<blockquote> 10693<p> 10694For purposes of determining the presence of a data race, 10695member functions do not modify <tt>const shared_ptr</tt> and 10696const <tt>weak_ptr</tt> arguments, nor any objects they 10697refer to. [<i>Note:</i> This is true in spite of that fact that such functions often 10698cause a change in <tt>use_count()</tt> <i>--end note</i>] 10699</p> 10700</blockquote> 10701<p> 10702On looking at the text, I'm not sure we need a similar disclaimer 10703anywhere else, since nothing else has the problem with the modified 10704<tt>use_count()</tt>. I think Howard arrived at a similar conclusion. 10705</p> 10706 10707 10708 10709 10710 10711<hr> 10712<h3><a name="900"></a>900. stream move-assignment</h3> 10713<p><b>Section:</b> 27.9.1.8 [ifstream.assign] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 10714 <b>Submitter:</b> Niels Dekker <b>Opened:</b> 2008-09-20 <b>Last modified:</b> 2009-10-20</p> 10715<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 10716<p><b>Discussion:</b></p> 10717<p> 10718It 10719appears that we have an issue similar to issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#675">675</a> regarding the move-assignment of 10720stream types. For example, when assigning to an <tt>std::ifstream</tt>, 10721<tt>ifstream1</tt>, it seems preferable to close the file originally held by 10722<tt>ifstream1</tt>: 10723</p> 10724 10725<blockquote><pre>ifstream1 = std::move(ifstream2); 10726</pre></blockquote> 10727 10728<p> 10729The current Draft 10730(<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2723.pdf">N2723</a>) 10731specifies that the move-assignment of 10732stream types like <tt>ifstream</tt> has the same effect as a swap: 10733</p> 10734 10735<blockquote> 10736<p> 10737Assign and swap 27.9.1.8 [ifstream.assign] 10738</p> 10739<pre>basic_ifstream& operator=(basic_ifstream&& rhs); 10740</pre> 10741<blockquote> 10742<i>Effects:</i> <tt>swap(rhs)</tt>. 10743</blockquote> 10744</blockquote> 10745 10746<p><i>[ 10747Batavia (2009-05): 10748]</i></p> 10749 10750<blockquote> 10751<p> 10752Howard agrees with the analysis and the direction proposed. 10753</p> 10754<p> 10755Move to Open pending specific wording to be supplied by Howard. 10756</p> 10757</blockquote> 10758 10759<p><i>[ 107602009-07 Frankfurt: 10761]</i></p> 10762 10763 10764<blockquote> 10765Howard is going to write wording. 10766</blockquote> 10767 10768<p><i>[ 107692009-07-26 Howard provided wording. 10770]</i></p> 10771 10772 10773<p><i>[ 107742009-09-13 Niels adds: 10775]</i></p> 10776 10777 10778<blockquote> 10779Note: The proposed change of 27.9.1.3 [filebuf.assign]/1 depends on the 10780resolution of LWG <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1204">1204</a>, which allows implementations to assume that 10781<tt>*this</tt> and <tt>rhs</tt> refer to different objects. 10782</blockquote> 10783 10784<p><i>[ 107852009 Santa Cruz: 10786]</i></p> 10787 10788 10789<blockquote> 10790Leave as Open. Too closely related to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#911">911</a> to move on at this time. 10791</blockquote> 10792 10793 10794 10795<p><b>Proposed resolution:</b></p> 10796 10797<p> 10798Change 27.8.1.2 [stringbuf.assign]/1: 10799</p> 10800 10801<blockquote><pre>basic_stringbuf& operator=(basic_stringbuf&& rhs); 10802</pre> 10803<blockquote> 10804-1- <i>Effects:</i> <del><tt>swap(rhs)</tt>.</del> 10805<ins>After the move assignment <tt>*this</tt> reflects the same observable 10806state it would have if it had been move constructed from <tt>rhs</tt> 10807(27.8.1.1 [stringbuf.cons]). 10808</ins> 10809</blockquote> 10810</blockquote> 10811 10812<p> 10813Change 27.8.2.2 [istringstream.assign]/1: 10814</p> 10815 10816<blockquote><pre>basic_istringstream& operator=(basic_istringstream&& rhs); 10817</pre> 10818<blockquote> 10819-1- <i>Effects:</i> <del><tt>swap(rhs)</tt>.</del> 10820<ins>Move assigns the base and members of <tt>*this</tt> with the respective 10821base and members of <tt>rhs</tt>. 10822</ins> 10823</blockquote> 10824</blockquote> 10825 10826<p> 10827Change 27.8.3.2 [ostringstream.assign]/1: 10828</p> 10829 10830<blockquote><pre>basic_ostringstream& operator=(basic_ostringstream&& rhs); 10831</pre> 10832<blockquote> 10833-1- <i>Effects:</i> <del><tt>swap(rhs)</tt>.</del> 10834<ins>Move assigns the base and members of <tt>*this</tt> with the respective 10835base and members of <tt>rhs</tt>. 10836</ins> 10837</blockquote> 10838</blockquote> 10839 10840<p> 10841Change 27.8.5.1 [stringstream.assign]/1: 10842</p> 10843 10844<blockquote><pre>basic_stringstream& operator=(basic_stringstream&& rhs); 10845</pre> 10846<blockquote> 10847-1- <i>Effects:</i> <del><tt>swap(rhs)</tt>.</del> 10848<ins>Move assigns the base and members of <tt>*this</tt> with the respective 10849base and members of <tt>rhs</tt>. 10850</ins> 10851</blockquote> 10852</blockquote> 10853 10854<p> 10855Change 27.9.1.3 [filebuf.assign]/1: 10856</p> 10857 10858<blockquote><pre>basic_filebuf& operator=(basic_filebuf&& rhs); 10859</pre> 10860<blockquote> 10861-1- <i>Effects:</i> <del><tt>swap(rhs)</tt>.</del> 10862<ins>Begins by calling <tt>this->close()</tt>. 10863After the move assignment <tt>*this</tt> reflects the same observable 10864state it would have if it had been move constructed from <tt>rhs</tt> 10865(27.9.1.2 [filebuf.cons]). 10866</ins> 10867</blockquote> 10868</blockquote> 10869 10870<p> 10871Change 27.9.1.8 [ifstream.assign]/1: 10872</p> 10873 10874<blockquote><pre>basic_ifstream& operator=(basic_ifstream&& rhs); 10875</pre> 10876<blockquote> 10877-1- <i>Effects:</i> <del><tt>swap(rhs)</tt>.</del> 10878<ins>Move assigns the base and members of <tt>*this</tt> with the respective 10879base and members of <tt>rhs</tt>.</ins> 10880</blockquote> 10881</blockquote> 10882 10883<p> 10884Change 27.9.1.12 [ofstream.assign]/1: 10885</p> 10886 10887<blockquote><pre>basic_ofstream& operator=(basic_ofstream&& rhs); 10888</pre> 10889<blockquote> 10890-1- <i>Effects:</i> <del><tt>swap(rhs)</tt>.</del> 10891<ins>Move assigns the base and members of <tt>*this</tt> with the respective 10892base and members of <tt>rhs</tt>.</ins> 10893</blockquote> 10894</blockquote> 10895 10896<p> 10897Change 27.9.1.16 [fstream.assign]/1: 10898</p> 10899 10900<blockquote><pre>basic_fstream& operator=(basic_fstream&& rhs); 10901</pre> 10902<blockquote> 10903-1- <i>Effects:</i> <del><tt>swap(rhs)</tt>.</del> 10904<ins>Move assigns the base and members of <tt>*this</tt> with the respective 10905base and members of <tt>rhs</tt>.</ins> 10906</blockquote> 10907</blockquote> 10908 10909 10910 10911 10912 10913 10914<hr> 10915<h3><a name="910"></a>910. Effects of MoveAssignable</h3> 10916<p><b>Section:</b> 20.2.1 [utility.arg.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 10917 <b>Submitter:</b> Alberto Ganesh Barbati <b>Opened:</b> 2008-09-29 <b>Last modified:</b> 2009-11-03</p> 10918<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#utility.arg.requirements">active issues</a> in [utility.arg.requirements].</p> 10919<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#utility.arg.requirements">issues</a> in [utility.arg.requirements].</p> 10920<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 10921<p><b>Discussion:</b></p> 10922<p><b>Addresses UK 150</b></p> 10923 10924<p> 10925The description of the effect of <tt>operator=</tt> in the <tt>MoveAssignable</tt> 10926concept, given in paragraph 7 is: 10927</p> 10928 10929<blockquote><pre>result_type T::operator=(T&& rv); // inherited from HasAssign<T, T&&> 10930</pre> 10931 10932<blockquote> 10933<i>Postconditions:</i> the constructed <tt>T</tt> object is equivalent to the value of 10934<tt>rv</tt> before the assignment. [<i>Note:</i> there is no 10935requirement on the value of <tt>rv</tt> after the assignment. <i>--end note</i>] 10936</blockquote> 10937</blockquote> 10938 10939<p> 10940The sentence contains a typo (what is the "constructed <tt>T</tt> object"?) 10941probably due to a cut&paste from <tt>MoveConstructible</tt>. Moreover, the 10942discussion of LWG issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#675">675</a> shows that the postcondition is too generic 10943and might not reflect the user expectations. An implementation of the 10944move assignment that just calls <tt>swap()</tt> would always fulfill the 10945postcondition as stated, but might have surprising side-effects in case 10946the source rvalue refers to an object that is not going to be 10947immediately destroyed. See LWG issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#900">900</a> for another example. Due to 10948the sometimes intangible nature of the "user expectation", it seems 10949difficult to have precise normative wording that could cover all cases 10950without introducing unnecessary restrictions. However a non-normative 10951clarification could be a very helpful warning sign that swapping is not 10952always the correct thing to do. 10953</p> 10954 10955<p><i>[ 109562009-05-09 Alisdair adds: 10957]</i></p> 10958 10959 10960<blockquote> 10961<p> 10962Issue 910 is exactly the reason BSI advanced the Editorial comment UK-150. 10963</p> 10964<p> 10965The post-conditions after assignment are at a minimum that the object 10966referenced by rv must be safely destructible, and the transaction should not 10967leak resources. Ideally it should be possible to simply assign rv a new 10968valid state after the call without invoking undefined behaviour, but any 10969other use of the referenced object would depend upon additional guarantees 10970made by that type. 10971</p> 10972</blockquote> 10973 10974<p><i>[ 109752009-05-09 Howard adds: 10976]</i></p> 10977 10978 10979<blockquote> 10980<p> 10981The intent of the rvalue reference work is that the moved from <tt>rv</tt> is 10982a valid object. Not one in a singular state. If, for example, the moved from 10983object is a <tt>vector</tt>, one should be able to do anything on that moved-from 10984<tt>vector</tt> that you can do with any other <tt>vector</tt>. However you would 10985first have to query it to find out what its current state is. E.g. it might have <tt>capacity</tt>, 10986it might not. It might have a non-zero <tt>size</tt>, it might not. But regardless, 10987you can <tt>push_back</tt> on to it if you want. 10988</p> 10989 10990<p> 10991That being said, most standard code is now conceptized. That is, the concepts 10992list the only operations that can be done with templated types - whether or not 10993the values have been moved from. 10994</p> 10995 10996<p> 10997Here is user-written code which must be allowed to be legal: 10998</p> 10999<blockquote><pre>#include <vector> 11000#include <cstdio> 11001 11002template <class Allocator> 11003void 11004inspect(std::vector<double, Allocator>&& v) 11005{ 11006 std::vector<double, Allocator> result(move(v)); 11007 std::printf("moved from vector has %u size and %u capacity\n", v.size(), v.capacity()); 11008 std::printf("The contents of the vector are:\n"); 11009 typedef typename std::vector<double, Allocator>::iterator I; 11010 for (I i = v.begin(), e = v.end(); i != e; ++i) 11011 printf("%f\n", *i); 11012} 11013 11014int main() 11015{ 11016 std::vector<double> v1(100, 5.5); 11017 inspect(move(v1)); 11018} 11019</pre></blockquote> 11020 11021<p> 11022The above program does not treat the moved-from <tt>vector</tt> as singular. It 11023only treats it as a <tt>vector</tt> with an unknown value. 11024</p> 11025<p> 11026I believe the current proposed wording is consistent with my view on this. 11027</p> 11028</blockquote> 11029 11030<p><i>[ 11031Batavia (2009-05): 11032]</i></p> 11033 11034<blockquote> 11035We agree that the proposed resolution 11036is an improvement over the current wording. 11037</blockquote> 11038 11039<p><i>[ 110402009-07 Frankfurt: 11041]</i></p> 11042 11043 11044<blockquote> 11045Need to look at again without concepts. 11046</blockquote> 11047 11048<p><i>[ 110492009-07 Frankfurt: 11050]</i></p> 11051 11052 11053<blockquote> 11054Walter will consult with Dave and Doug. 11055</blockquote> 11056 11057<p><i>[ 110582009-10 Santa Cruz: 11059]</i></p> 11060 11061 11062<blockquote> 11063We believe this is handled by the resolution to issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1204">1204</a>, 11064but there is to much going on in this area to be sure. Defer for now. 11065</blockquote> 11066 11067 11068 11069<p><b>Proposed resolution:</b></p> 11070<p> 11071In [concept.copymove], replace the postcondition in paragraph 7 with: 11072</p> 11073 11074<blockquote> 11075<i>Postconditions:</i> <tt>*this</tt> is equivalent to the value of <tt>rv</tt> before the 11076assignment. [<i>Note:</i> there is no requirement on the value of <tt>rv</tt> after the 11077assignment, but the 11078effect should be unsurprising to the user even in case <tt>rv</tt> is not 11079immediately destroyed. This may require that resources previously owned 11080by <tt>*this</tt> are released instead of transferred to <tt>rv</tt>. <i>-- end note</i>] 11081</blockquote> 11082 11083 11084 11085 11086 11087<hr> 11088<h3><a name="911"></a>911. I/O streams and <tt>move/swap</tt> semantic</h3> 11089<p><b>Section:</b> 27.7.1 [input.streams], 27.7.2 [output.streams] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 11090 <b>Submitter:</b> Alberto Ganesh Barbati <b>Opened:</b> 2008-09-29 <b>Last modified:</b> 2009-10-20</p> 11091<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 11092<p><b>Discussion:</b></p> 11093<p> 11094Class template <tt>basic_istream</tt>, <tt>basic_ostream</tt> and <tt>basic_iostream</tt> 11095implements public move constructors, move assignment operators and <tt>swap</tt> 11096method and free functions. This might induce both the user and the 11097compiler to think that those types are <tt>MoveConstructible</tt>, <tt>MoveAssignable</tt> 11098and <tt>Swappable</tt>. However, those class templates fail to fulfill the user 11099expectations. For example: 11100</p> 11101 11102<blockquote><pre>std::ostream os(std::ofstream("file.txt")); 11103assert(os.rdbuf() == 0); // buffer object is not moved to os, file.txt has been closed 11104 11105std::vector<std::ostream> v; 11106v.push_back(std::ofstream("file.txt")); 11107v.reserve(100); // causes reallocation 11108assert(v[0].rdbuf() == 0); // file.txt has been closed! 11109 11110std::ostream&& os1 = std::ofstream("file1.txt"); 11111os1 = std::ofstream("file2.txt"); 11112os1 << "hello, world"; // still writes to file1.txt, not to file2.txt! 11113 11114std::ostream&& os1 = std::ofstream("file1.txt"); 11115std::ostream&& os2 = std::ofstream("file2.txt"); 11116std::swap(os1, os2); 11117os1 << "hello, world"; // writes to file1.txt, not to file2.txt! 11118</pre></blockquote> 11119 11120<p> 11121This is because the move constructor, the move assignment operator and 11122<tt>swap</tt> are all implemented through calls to <tt>std::basic_ios</tt> member 11123functions <tt>move()</tt> and <tt>swap()</tt> that do not move nor swap the controlled 11124stream buffers. That can't happen because the stream buffers may have 11125different types. 11126</p> 11127 11128<p> 11129Notice that for <tt>basic_streambuf</tt>, the member function <tt>swap()</tt> is 11130protected. I believe that is correct and all of <tt>basic_istream</tt>, 11131<tt>basic_ostream</tt>, <tt>basic_iostream</tt> should do the same as the move ctor, move 11132assignment operator and swap member function are needed by the derived 11133<tt>fstream</tt>s and <tt>stringstream</tt>s template. The free swap functions for 11134<tt>basic_(i|o|io)stream</tt> templates should be removed for the same reason. 11135</p> 11136 11137<p><i>[ 11138Batavia (2009-05): 11139]</i></p> 11140 11141<blockquote> 11142<p> 11143We note that the rvalue swap functions have already been removed. 11144</p> 11145<p> 11146Bill is unsure about making the affected functions protected; 11147he believes they may need to be public. 11148</p> 11149<p> 11150We are also unsure about removing the lvalue swap functions as proposed. 11151</p> 11152<p> 11153Move to Open. 11154</p> 11155</blockquote> 11156 11157<p><i>[ 111582009-07 Frankfurt: 11159]</i></p> 11160 11161 11162<blockquote> 11163<p> 11164It's not clear that the use case is compelling. 11165</p> 11166<p> 11167Howard: This needs to be implemented and tested. 11168</p> 11169</blockquote> 11170 11171<p><i>[ 111722009-07-26 Howard adds: 11173]</i></p> 11174 11175 11176<blockquote> 11177<p> 11178I started out thinking I would recommend NAD for this one. I've turned around 11179to agree with the proposed resolution (which I've updated to the current draft). 11180I did not fully understand Ganesh's rationale, and attempt to describe my 11181improved understanding below. 11182</p> 11183 11184<p> 11185The move constructor, move assignment operator, and swap function are different 11186for <tt>basic_istream</tt>, <tt>basic_ostream</tt> and <tt>basic_iostream</tt> 11187than other classes. A timely conversation with Daniel reminded me of this long 11188forgotten fact. These members are sufficiently different that they would be 11189extremely confusing to use in general, but they are very much needed for derived 11190clients. 11191</p> 11192 11193<ul> 11194<li> 11195The move constructor moves everything but the <tt>rdbuf</tt> pointer. 11196</li> 11197<li> 11198The move assignment operator moves everything but the <tt>rdbuf</tt> pointer. 11199</li> 11200<li> 11201The swap function swaps everything but the <tt>rdbuf</tt> pointer. 11202</li> 11203</ul> 11204 11205<p> 11206The reason for this behavior is that for the std-derived classes (stringstreams, 11207filestreams), the <tt>rdbuf</tt> pointer points back into the class itself 11208(self referencing). It can't be swapped or moved. But this fact isn't born out 11209at the <tt>stream</tt> level. Rather it is born out at the <tt>fstream</tt>/<tt>sstream</tt> 11210level. And the lower levels just need to deal with that fact by not messing around 11211with the <tt>rdbuf</tt> pointer which is stored down at the lower levels. 11212</p> 11213 11214<p> 11215In a nutshell, it is very confusing for all of those who are not so intimately 11216related with streams that they've implemented them. And it is even fairly 11217confusing for some of those who have (including myself). I do not think it is 11218safe to swap or move <tt>istreams</tt> or <tt>ostreams</tt> because this will 11219(by necessary design) separate stream state from streambuffer state. Derived 11220classes (such as <tt>fstream</tt> and <tt>stringstream</tt> must be used to 11221keep the stream state and stream buffer consistently packaged as one unit during 11222a move or swap. 11223</p> 11224 11225<p> 11226I've implemented this proposal and am living with it day to day. 11227</p> 11228 11229</blockquote> 11230 11231<p><i>[ 112322009 Santa Cruz: 11233]</i></p> 11234 11235 11236<blockquote> 11237Leave Open. Pablo expected to propose alternative wording which would rename 11238move construction, move assignment and swap, and may or may not make them 11239protected. This will impact issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#900">900</a>. 11240</blockquote> 11241 11242 11243 11244<p><b>Proposed resolution:</b></p> 11245<p> 1124627.7.1.1 [istream]: make the following member functions protected: 11247</p> 11248 11249<blockquote><pre>basic_istream(basic_istream&& rhs); 11250basic_istream& operator=(basic_istream&& rhs); 11251void swap(basic_istream& rhs); 11252</pre></blockquote> 11253 11254<p> 11255Ditto: remove the swap free function signature 11256</p> 11257 11258<blockquote><pre><del>// swap: 11259template <class charT, class traits> 11260 void swap(basic_istream<charT, traits>& x, basic_istream<charT, traits>& y);</del> 11261</pre></blockquote> 11262 11263<p> 1126427.7.1.1.2 [istream.assign]: remove paragraph 4 11265</p> 11266 11267<blockquote><pre><del>template <class charT, class traits> 11268 void swap(basic_istream<charT, traits>& x, basic_istream<charT, traits>& y);</del> 11269</pre> 11270<blockquote> 11271<del><i>Effects:</i> <tt>x.swap(y)</tt>.</del> 11272</blockquote> 11273</blockquote> 11274 11275<p> 1127627.7.1.5 [iostreamclass]: make the following member function protected: 11277</p> 11278 11279<blockquote><pre>basic_iostream(basic_iostream&& rhs); 11280basic_iostream& operator=(basic_iostream&& rhs); 11281void swap(basic_iostream& rhs); 11282</pre></blockquote> 11283 11284<p> 11285Ditto: remove the swap free function signature 11286</p> 11287 11288<blockquote><pre><del>template <class charT, class traits> 11289 void swap(basic_iostream<charT, traits>& x, basic_iostream<charT, traits>& y);</del> 11290</pre></blockquote> 11291 11292<p> 1129327.7.1.5.3 [iostream.assign]: remove paragraph 3 11294</p> 11295 11296<blockquote><pre><del>template <class charT, class traits> 11297 void swap(basic_iostream<charT, traits>& x, basic_iostream<charT, traits>& y);</del> 11298</pre> 11299<blockquote> 11300<del><i>Effects:</i> <tt>x.swap(y)</tt>.</del> 11301</blockquote> 11302</blockquote> 11303 11304<p> 1130527.7.2.1 [ostream]: make the following member function protected: 11306</p> 11307 11308<blockquote><pre>basic_ostream(basic_ostream&& rhs); 11309basic_ostream& operator=(basic_ostream&& rhs); 11310void swap(basic_ostream& rhs); 11311</pre></blockquote> 11312 11313<p> 11314Ditto: remove the swap free function signature 11315</p> 11316 11317<blockquote><pre><del>// swap: 11318template <class charT, class traits> 11319 void swap(basic_ostream<charT, traits>& x, basic_ostream<charT, traits>& y);</del> 11320</pre></blockquote> 11321 11322<p> 1132327.7.2.3 [ostream.assign]: remove paragraph 4 11324</p> 11325 11326<blockquote><pre><del>template <class charT, class traits> 11327 void swap(basic_ostream<charT, traits>& x, basic_ostream<charT, traits>& y);</del> 11328</pre> 11329<blockquote> 11330<del><i>Effects:</i> <tt>x.swap(y)</tt>.</del> 11331</blockquote> 11332</blockquote> 11333 11334 11335 11336 11337 11338 11339<hr> 11340<h3><a name="915"></a>915. <tt>minmax</tt> with <tt>initializer_list</tt> should return 11341<tt>pair</tt> of <tt>T</tt>, not <tt>pair</tt> of <tt>const T&</tt></h3> 11342<p><b>Section:</b> 25.4.7 [alg.min.max] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 11343 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2008-10-04 <b>Last modified:</b> 2009-10-23</p> 11344<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#alg.min.max">issues</a> in [alg.min.max].</p> 11345<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 11346<p><b>Discussion:</b></p> 11347<p> 11348It seems that the proposed changes for 11349<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2772.pdf">N2772</a> 11350were not clear enough in 11351this point: 11352</p> 11353 11354<blockquote> 1135525.4.7 [alg.min.max], before p.23 + p.24 + before p. 27 + p. 28 say that the return 11356type of the <tt>minmax</tt> overloads with an <tt>initializer_list</tt> is 11357<tt>pair<const T&, const T&></tt>, 11358which is inconsistent with the decision for the other <tt>min/max</tt> overloads which take 11359a <tt>initializer_list</tt> as argument and return a <tt>T</tt>, not a <tt>const T&</tt>. 11360Doing otherwise for <tt>minmax</tt> would easily lead to unexpected life-time 11361problems by using <tt>minmax</tt> instead of <tt>min</tt> and <tt>max</tt> separately. 11362</blockquote> 11363 11364<p><i>[ 11365Batavia (2009-05): 11366]</i></p> 11367 11368<blockquote> 11369We agree with the proposed resolution. 11370Move to Tentatively Ready. 11371</blockquote> 11372 11373<p><i>[ 113742009-07 Frankfurt 11375]</i></p> 11376 11377 11378<blockquote> 11379Moved from Tentatively Ready to Open only because the wording needs to be 11380tweaked for concepts removal. 11381</blockquote> 11382 11383<p><i>[ 113842009-08-18 Daniel adds: 11385]</i></p> 11386 11387 11388<blockquote> 11389Recommend NAD since the proposed changes have already been performed 11390as part of editorial work of 11391<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2914.pdf">N2914</a>. 11392</blockquote> 11393 11394<p><i>[ 113952009-10 Santa Cruz: 11396]</i></p> 11397 11398 11399<blockquote> 11400Can't find initializer_list form of minmax anymore, only variadic 11401version. Seems like we had an editing clash with concepts. Leave Open, 11402at least until editorial issues resolved. Bring this to Editor's 11403attention. 11404</blockquote> 11405 11406 11407 11408<p><b>Proposed resolution:</b></p> 11409<ol> 11410<li> 11411<p> 11412In 25 [algorithms]/2, header <tt><algorithm></tt> synopsis change as indicated: 11413</p> 11414 11415<blockquote><pre>template<<del>class</del><ins>LessThanComparable</ins> T> 11416<ins>requires CopyConstructible<T></ins> 11417pair<<del>const </del>T<del>&</del>, <del>const </del>T<del>&</del>> 11418minmax(initializer_list<T> t); 11419 11420template<class T, <del>class</del><ins>StrictWeakOrder<auto, T></ins> Compare> 11421<ins>requires CopyConstructible<T></ins> 11422pair<<del>const </del>T<del>&</del>, <del>const </del>T<del>&</del>> 11423minmax(initializer_list<T> t, Compare comp); 11424</pre></blockquote> 11425</li> 11426<li> 11427<p> 11428In 25.4.7 [alg.min.max] change as indicated (Begin: Just before p.20): 11429</p> 11430<blockquote><pre>template<<del>class</del><ins>LessThanComparable</ins> T> 11431 <ins>requires CopyConstructible<T></ins> 11432 pair<<del>const </del>T<del>&</del>, <del>const </del>T<del>&</del>> 11433 minmax(initializer_list<T> t); 11434</pre> 11435<blockquote> 11436<p> 11437<del>-20- <i>Requires:</i> <tt>T</tt> is <tt>LessThanComparable</tt> and 11438<tt>CopyConstructible</tt>.</del> 11439</p> 11440<p> 11441-21- <i>Returns:</i> <tt>pair<<del>const </del>T<del>&</del>, <del>const 11442</del>T<del>&</del>>(x, y)</tt> where <tt>x</tt> is the 11443smallest value and <tt>y</tt> the largest value in the <tt>initializer_list</tt>. 11444</p> 11445</blockquote> 11446 11447<p>[..]</p> 11448<pre>template<class T, <del>class</del><ins>StrictWeakOrder<auto, T></ins> Compare> 11449 <ins>requires CopyConstructible<T></ins> 11450 pair<<del>const </del>T<del>&</del>, <del>const </del>T<del>&</del>> 11451 minmax(initializer_list<T> t, Compare comp); 11452</pre> 11453 11454<blockquote> 11455<p> 11456<del>-24- <i>Requires:</i> type <tt>T</tt> is <tt>LessThanComparable</tt> and <tt>CopyConstructible</tt>.</del> 11457</p> 11458<p> 11459-25- <i>Returns:</i> <tt>pair<<del>const </del>T<del>&</del>, <del>const 11460</del>T<del>&</del>>(x, y)</tt> where <tt>x</tt> is the 11461smallest value and <tt>y</tt> largest value in the <tt>initializer_list</tt>. 11462</p> 11463</blockquote> 11464</blockquote> 11465</li> 11466</ol> 11467 11468 11469 11470 11471 11472 11473<hr> 11474<h3><a name="920"></a>920. Ref-qualification support in the library</h3> 11475<p><b>Section:</b> 20.7.14 [func.memfn] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 11476 <b>Submitter:</b> Bronek Kozicki <b>Opened:</b> 2008-10-06 <b>Last modified:</b> 2009-10-23</p> 11477<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#func.memfn">issues</a> in [func.memfn].</p> 11478<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 11479<p><b>Duplicate of:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1230">1230</a></p> 11480<p><b>Discussion:</b></p> 11481<p> 11482Daniel Kr�gler wrote: 11483</p> 11484 11485<blockquote> 11486<p> 11487Shouldn't above list be completed for &- and &&-qualified 11488member functions This would cause to add: 11489</p> 11490<blockquote><pre>template<Returnable R, class T, CopyConstructible... Args> 11491unspecified mem_fn(R (T::* pm)(Args...) &); 11492template<Returnable R, class T, CopyConstructible... Args> 11493unspecified mem_fn(R (T::* pm)(Args...) const &); 11494template<Returnable R, class T, CopyConstructible... Args> 11495unspecified mem_fn(R (T::* pm)(Args...) volatile &); 11496template<Returnable R, class T, CopyConstructible... Args> 11497unspecified mem_fn(R (T::* pm)(Args...) const volatile &); 11498template<Returnable R, class T, CopyConstructible... Args> 11499unspecified mem_fn(R (T::* pm)(Args...) &&); 11500template<Returnable R, class T, CopyConstructible... Args> 11501unspecified mem_fn(R (T::* pm)(Args...) const &&); 11502template<Returnable R, class T, CopyConstructible... Args> 11503unspecified mem_fn(R (T::* pm)(Args...) volatile &&); 11504template<Returnable R, class T, CopyConstructible... Args> 11505unspecified mem_fn(R (T::* pm)(Args...) const volatile &&); 11506</pre></blockquote> 11507 11508</blockquote> 11509 11510<p> 11511yes, absolutely. Thanks for spotting this. Without this change <tt>mem_fn</tt> 11512cannot be initialized from pointer to ref-qualified member function. I 11513believe semantics of such function pointer is well defined. 11514</p> 11515 11516<p><i>[ 11517Post Summit Daniel provided wording. 11518]</i></p> 11519 11520 11521<p><i>[ 11522Batavia (2009-05): 11523]</i></p> 11524 11525<blockquote> 11526<p> 11527We need to think about whether we really want to go down the proposed path 11528of combinatorial explosion. 11529Perhaps a Note would suffice. 11530</p> 11531<p> 11532We would really like to have an implementation before proceeding. 11533</p> 11534<p> 11535Move to Open, and recommend this be deferred until after the next 11536Committee Draft has been issued. 11537</p> 11538</blockquote> 11539 11540<p><i>[ 115412009-10-10 Daniel updated wording to post-concepts. 11542]</i></p> 11543 11544 11545<blockquote> 11546<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1230">1230</a> has a similar proposed resolution 11547</blockquote> 11548 11549<p><i>[ 115502009-10 Santa Cruz: 11551]</i></p> 11552 11553 11554<blockquote> 11555Move to Ready. 11556</blockquote> 11557 11558 11559 11560<p><b>Proposed resolution:</b></p> 11561<ol> 11562<li> 11563<p> 11564Change 20.7 [function.objects]/2, header 11565<tt><functional></tt> synopsis as follows: 11566</p> 11567 11568<blockquote><pre>// 20.7.14, member function adaptors: 11569template<class R, class T> <i>unspecified</i> mem_fn(R T::*); 11570 11571<ins>template<class R, class T, class ...Args> <i>unspecified</i> mem_fn(R (T::*)(Args...));</ins> 11572<ins>template<class R, class T, class ...Args> <i>unspecified</i> mem_fn(R (T::*)(Args...) const);</ins> 11573<ins>template<class R, class T, class ...Args> <i>unspecified</i> mem_fn(R (T::*)(Args...) volatile);</ins> 11574<ins>template<class R, class T, class ...Args> <i>unspecified</i> mem_fn(R (T::*)(Args...) const volatile);</ins> 11575 11576<ins>template<class R, class T, class ...Args> <i>unspecified</i> mem_fn(R (T::*)(Args...) &);</ins> 11577<ins>template<class R, class T, class ...Args> <i>unspecified</i> mem_fn(R (T::*)(Args...) const &);</ins> 11578<ins>template<class R, class T, class ...Args> <i>unspecified</i> mem_fn(R (T::*)(Args...) volatile &);</ins> 11579<ins>template<class R, class T, class ...Args> <i>unspecified</i> mem_fn(R (T::*)(Args...) const volatile &);</ins> 11580 11581<ins>template<class R, class T, class ...Args> <i>unspecified</i> mem_fn(R (T::*)(Args...) &&);</ins> 11582<ins>template<class R, class T, class ...Args> <i>unspecified</i> mem_fn(R (T::*)(Args...) const &&);</ins> 11583<ins>template<class R, class T, class ...Args> <i>unspecified</i> mem_fn(R (T::*)(Args...) volatile &&);</ins> 11584<ins>template<class R, class T, class ...Args> <i>unspecified</i> mem_fn(R (T::*)(Args...) const volatile &&);</ins> 11585</pre></blockquote> 11586</li> 11587 11588<li> 11589<p> 11590Change the prototype list of 20.7.14 [func.memfn] as follows [NB: The 11591following text, most notably p.2 and p.3 which 11592discuss influence of the cv-qualification on the definition of the 11593base class's first template parameter remains 11594unchanged. ]: 11595</p> 11596 11597<blockquote><pre>template<class R, class T> <i>unspecified</i> mem_fn(R T::* pm); 11598 11599<ins>template<class R, class T, class ...Args> <i>unspecified</i> mem_fn(R (T::* pm)(Args...));</ins> 11600<ins>template<class R, class T, class ...Args> <i>unspecified</i> mem_fn(R (T::* pm)(Args...) const);</ins> 11601<ins>template<class R, class T, class ...Args> <i>unspecified</i> mem_fn(R (T::* pm)(Args...) volatile);</ins> 11602<ins>template<class R, class T, class ...Args> <i>unspecified</i> mem_fn(R (T::* pm)(Args...) const volatile);</ins> 11603 11604<ins>template<class R, class T, class ...Args> <i>unspecified</i> mem_fn(R (T::* pm)(Args...) &);</ins> 11605<ins>template<class R, class T, class ...Args> <i>unspecified</i> mem_fn(R (T::* pm)(Args...) const &);</ins> 11606<ins>template<class R, class T, class ...Args> <i>unspecified</i> mem_fn(R (T::* pm)(Args...) volatile &);</ins> 11607<ins>template<class R, class T, class ...Args> <i>unspecified</i> mem_fn(R (T::* pm)(Args...) const volatile &);</ins> 11608 11609<ins>template<class R, class T, class ...Args> <i>unspecified</i> mem_fn(R (T::* pm)(Args...) &&);</ins> 11610<ins>template<class R, class T, class ...Args> <i>unspecified</i> mem_fn(R (T::* pm)(Args...) const &&);</ins> 11611<ins>template<class R, class T, class ...Args> <i>unspecified</i> mem_fn(R (T::* pm)(Args...) volatile &&);</ins> 11612<ins>template<class R, class T, class ...Args> <i>unspecified</i> mem_fn(R (T::* pm)(Args...) const volatile &&);</ins> 11613</pre></blockquote> 11614</li> 11615 11616<li> 11617<p> 11618Remove 20.7.14 [func.memfn]/5: 11619</p> 11620 11621<blockquote> 11622<del><i>Remarks:</i> Implementations may implement <tt>mem_fn</tt> as a set of 11623overloaded function templates.</del> 11624</blockquote> 11625</li> 11626</ol> 11627 11628 11629 11630 11631 11632 11633<hr> 11634<h3><a name="921"></a>921. Rational Arithmetic should use template aliases</h3> 11635<p><b>Section:</b> 20.4.1 [ratio.ratio] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 11636 <b>Submitter:</b> Pablo Halpern <b>Opened:</b> 2008-10-07 <b>Last modified:</b> 2009-10-21</p> 11637<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#ratio.ratio">issues</a> in [ratio.ratio].</p> 11638<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 11639<p><b>Discussion:</b></p> 11640<p> 11641The compile-time functions that operate on <tt>ratio<N,D></tt> require the 11642cumbersome and error-prone "evaluation" of a <tt>type</tt> member using a 11643meta-programming style that predates the invention of template aliases. 11644Thus, multiplying three ratios <tt>a</tt>, <tt>b</tt>, and <tt>c</tt> requires the expression: 11645</p> 11646 11647<blockquote><pre>ratio_multiply<a, ratio_multiply<b, c>::type>::type 11648</pre></blockquote> 11649 11650<p> 11651The simpler expression: 11652</p> 11653 11654<blockquote><pre>ratio_multiply<a, ratio_multiply<b, c>> 11655</pre></blockquote> 11656 11657<p> 11658Could be used by if template aliases were employed in the definitions. 11659</p> 11660 11661<p><i>[ 11662Post Summit: 11663]</i></p> 11664 11665 11666<blockquote> 11667<p> 11668Jens: not a complete proposed resolution: "would need to make similar change" 11669</p> 11670<p> 11671Consensus: We agree with the direction of the issue. 11672</p> 11673<p> 11674Recommend Open. 11675</p> 11676</blockquote> 11677 11678<p><i>[ 116792009-05-11 Daniel adds: 11680]</i></p> 11681 11682 11683<blockquote> 11684<p> 11685Personally I'm <em>not</em> in favor for the addition of: 11686</p> 11687<blockquote><pre>typedef ratio type; 11688</pre></blockquote> 11689<p> 11690For a reader of the 11691standard it's usage or purpose is unclear. I haven't seen similar examples 11692of attempts to satisfy non-feature complete compilers. 11693</p> 11694</blockquote> 11695 11696<p><i>[ 116972009-05-11 Pablo adds: 11698]</i></p> 11699 11700 11701<blockquote> 11702<p> 11703The addition of type to the <tt>ratio</tt> template allows the previous style 11704(i.e., in the prototype implementations) to remain valid and permits the 11705use of transitional library implementations for C++03 compilers. I do 11706not feel strongly about its inclusion, however, and leave it up to the 11707reviewers to decide. 11708</p> 11709</blockquote> 11710 11711<p><i>[ 11712Batavia (2009-05): 11713]</i></p> 11714 11715<blockquote> 11716Bill asks for additional discussion in the issue 11717that spells out more details of the implementation. 11718Howard points us to issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#948">948</a> 11719which has at least most of the requested details. 11720Tom is strongly in favor of overflow-checking at compile time. 11721Pete points out that there is no change of functionality implied. 11722We agree with the proposed resolution, 11723but recommend moving the issue to Review 11724to allow time to improve the discussion if needed. 11725</blockquote> 11726 11727<p><i>[ 117282009-07-21 Alisdair adds: 11729]</i></p> 11730 11731 11732<blockquote> 11733See <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1121">1121</a> for a potentially incompatible proposal. 11734</blockquote> 11735 11736<p><i>[ 117372009-10 Santa Cruz: 11738]</i></p> 11739 11740 11741<blockquote> 11742Move to Ready. 11743</blockquote> 11744 11745 11746 11747<p><b>Proposed resolution:</b></p> 11748 11749 11750 <ol start="0"> 11751<li> 11752<p> 11753In 20.4 [ratio]/3 change as indicated: 11754</p> 11755 11756<blockquote><pre>// ratio arithmetic 11757template <class R1, class R2> <del>struct</del><ins>using</ins> ratio_add<ins> = <em>see below</em></ins>; 11758template <class R1, class R2> <del>struct</del><ins>using</ins> ratio_subtract<ins> = <em>see below</em></ins>; 11759template <class R1, class R2> <del>struct</del><ins>using</ins> ratio_multiply<ins> = <em>see below</em></ins>; 11760template <class R1, class R2> <del>struct</del><ins>using</ins> ratio_divide<ins> = <em>see below</em></ins>; 11761</pre></blockquote> 11762</li> 11763<li> 11764<p> 11765In 20.4.1 [ratio.ratio], change as indicated: 11766</p> 11767<blockquote><pre>namespace std { 11768 template <intmax_t N, intmax_t D = 1> 11769 class ratio { 11770 public: 11771 <ins>typedef ratio type;</ins> 11772 static const intmax_t num; 11773 static const intmax_t den; 11774 }; 11775} 11776</pre></blockquote> 11777</li> 11778<li> 11779<p> 11780In 20.4.2 [ratio.arithmetic] change as indicated: 11781</p> 11782 11783<blockquote><pre>template <class R1, class R2> <del>struct</del><ins>using</ins> ratio_add<ins> = <em>see below</em></ins><del>{ 11784 typedef <em>see below</em> type; 11785}</del>; 11786</pre> 11787 11788<blockquote> 11789<p> 117901 The <del>nested typedef</del> type <tt><ins>ratio_add<R1, R2></ins></tt> 11791shall be a synonym for <tt>ratio<T1, T2></tt> 11792where <tt>T1</tt> has the value <tt>R1::num * R2::den + R2::num * R1::den</tt> and <tt>T2</tt> 11793has the value <tt>R1::den * R2::den</tt>. 11794</p> 11795</blockquote> 11796</blockquote> 11797<blockquote><pre>template <class R1, class R2> <del>struct</del><ins>using</ins> ratio_subtract<ins> = <em>see below</em></ins><del>{ 11798 typedef <em>see below</em> type; 11799}</del>; 11800</pre> 11801<blockquote> 11802<p> 118032 The <del>nested typedef</del> type <tt><ins>ratio_subtract<R1, R2></ins></tt> 11804shall be a synonym for <tt>ratio<T1, T2></tt> 11805where <tt>T1</tt> has the value <tt>R1::num * R2::den - R2::num * R1::den</tt> and <tt>T2</tt> 11806has the value <tt>R1::den * R2::den</tt>. 11807</p> 11808</blockquote> 11809</blockquote> 11810<blockquote><pre>template <class R1, class R2> <del>struct</del><ins>using</ins> ratio_multiply<ins> = <em>see below</em></ins><del>{ 11811 typedef <em>see below</em> type; 11812}</del>; 11813</pre> 11814<blockquote> 11815<p> 118163 The <del>nested typedef</del> type <tt><ins>ratio_multiply<R1, R2></ins></tt> 11817shall be a synonym for <tt>ratio<T1, T2></tt> 11818where <tt>T1</tt> has the value <tt>R1::num * R2::num</tt> and <tt>T2</tt> has the value <tt>R1::den * R2::den</tt>. 11819</p> 11820</blockquote> 11821</blockquote> 11822<blockquote><pre>template <class R1, class R2> <del>struct</del><ins>using</ins> ratio_divide<ins> = <em>see below</em></ins><del>{ 11823 typedef <em>see below</em> type; 11824}</del>; 11825</pre> 11826<blockquote> 11827<p> 118284 The <del>nested typedef</del> type <tt><ins>ratio_divide<R1, R2></ins></tt> 11829shall be a synonym for <tt>ratio<T1, T2></tt> 11830where <tt>T1</tt> has the value <tt>R1::num * R2::den</tt> and <tt>T2</tt> has the value <tt>R1::den * R2::num</tt>. 11831</p> 11832</blockquote> 11833</blockquote> 11834</li> 11835<li> 11836<p> 11837In 20.9.3.1 [time.duration.cons]/4 change as indicated: 11838</p> 11839<blockquote> 11840<p> 11841<i>Requires:</i> <tt>treat_as_floating_point<rep>::value</tt> shall be true or 11842<tt>ratio_divide<Period2, period>::<del>type::</del>den</tt> shall be 1.[..] 11843</p> 11844</blockquote> 11845</li> 11846<li> 11847<p> 11848In 20.9.3.7 [time.duration.cast]/2 change as indicated: 11849</p> 11850<blockquote> 11851<p> 11852<i>Returns:</i> Let CF be <tt>ratio_divide<Period, typename 11853ToDuration::period><del>::type</del></tt>, and [..] 11854</p> 11855</blockquote> 11856</li> 11857</ol> 11858 11859 11860 11861 11862 11863<hr> 11864<h3><a name="929"></a>929. Thread constructor</h3> 11865<p><b>Section:</b> 30.3.1.2 [thread.thread.constr] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Review">Review</a> 11866 <b>Submitter:</b> Anthony Williams <b>Opened:</b> 2008-10-23 <b>Last modified:</b> 2009-10-25</p> 11867<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#thread.thread.constr">active issues</a> in [thread.thread.constr].</p> 11868<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#thread.thread.constr">issues</a> in [thread.thread.constr].</p> 11869<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Review">Review</a> status.</p> 11870<p><b>Discussion:</b></p> 11871 11872<p><b>Addresses UK 323</b></p> 11873 11874<p> 11875The <tt>thread</tt> constructor for starting a new thread with a function and 11876arguments is overly constrained by the signature requiring rvalue 11877references for <tt>func</tt> and <tt>args</tt> and the <tt>CopyConstructible</tt> requirements 11878for the elements of <tt>args</tt>. The use of an rvalue reference for the 11879function restricts the potential use of a plain function name, since 11880the type of the bound parameter will be deduced to be a function 11881reference and decay to pointer-to-function will not happen. This 11882therefore complicates the implementation in order to handle a simple 11883case. Furthermore, the use of rvalue references for args prevents the 11884array to pointer decay. Since arrays are not <tt>CopyConstructible</tt> or even 11885<tt>MoveConstructible</tt>, this essentially prevents the passing of arrays as 11886parameters. In particular it prevents the passing of string literals. 11887Consequently a simple case such as 11888</p> 11889 11890<blockquote><pre>void f(const char*); 11891std::thread t(f,"hello"); 11892</pre></blockquote> 11893 11894<p> 11895is ill-formed since the type of the string literal is <tt>const char[6]</tt>. 11896</p> 11897 11898<p> 11899By changing the signature to take all parameters by value we can 11900eliminate the <tt>CopyConstructible</tt> requirement and permit the use of 11901arrays, as the parameter passing semantics will cause the necessary 11902array-to-pointer decay. They will also cause the function name to 11903decay to a pointer to function and allow the implementation to handle 11904functions and function objects identically. 11905</p> 11906 11907<p> 11908The new signature of the <tt>thread</tt> constructor for a function and 11909arguments is thus: 11910</p> 11911 11912<blockquote><pre>template<typename F,typename... Args> 11913thread(F,Args... args); 11914</pre></blockquote> 11915 11916<p> 11917Since the parameter pack <tt>Args</tt> can be empty, the single-parameter 11918constructor that takes just a function by value is now redundant. 11919</p> 11920 11921<p><i>[ 11922Howard adds: 11923]</i></p> 11924 11925 11926<blockquote> 11927<p> 11928I agree with everything Anthony says in this issue. However I believe we 11929can optimize in such a way as to get the pass-by-value behavior with the 11930pass-by-rvalue-ref performance. The performance difference is that the latter 11931removes a <tt>move</tt> when passing in an lvalue. 11932</p> 11933 11934<p> 11935This circumstance is very analogous to <tt>make_pair</tt> (20.3.4 [pairs]) 11936where we started with passing by const reference, changed to pass by value to 11937get pointer decay, and then changed to pass by rvalue reference, but modified with 11938<tt>decay<T></tt> to retain the pass-by-value behavior. If we were to 11939apply the same solution here it would look like: 11940</p> 11941 11942<blockquote><pre><del>template <class F> explicit thread(F f);</del> 11943template <class F, class ...Args> thread(F&& f, Args&&... args); 11944</pre> 11945<blockquote> 11946<p> 11947-4- <i>Requires:</i> <tt>F</tt> and each <tt>Ti</tt> in <tt>Args</tt> shall be <del><tt>CopyConstructible</tt> 11948if an lvalue and otherwise</del> <tt>MoveConstructible</tt>. 11949<tt><i>INVOKE</i>(f, w1, w2, ..., wN)</tt> (20.7.2 [func.require]) shall be a valid expression for 11950some values <tt>w1, w2, ... , wN,</tt> where <tt>N == sizeof...(Args)</tt>. 11951</p> 11952<p> 11953-5- <i>Effects:</i> Constructs an object of type <tt>thread</tt> 11954<del>and executes <tt><i>INVOKE</i>(f, t1, t2, ..., tN)</tt> in a new 11955thread of execution, where <tt>t1, t2, ..., tN</tt> are the values in <tt>args...</tt></del>. 11956<ins>Constructs 11957the following objects in memory which is accessible to a new thread of execution 11958as if:</ins> 11959</p> 11960<blockquote><pre><ins>typename decay<F>::type g(std::forward<F>(f));</ins> 11961<ins>tuple<typename decay<Args>::type...> w(std::forward<Args>(args)...);</ins> 11962</pre></blockquote> 11963<p> 11964<ins>The new thread of 11965execution executes <tt><i>INVOKE</i>(g, wi...)</tt> where the <tt>wi...</tt> refers 11966to the elements stored in the <tt>tuple w</tt>.</ins> 11967Any return value from <tt>g</tt> is ignored. 11968<del>If <tt>f</tt> terminates with an uncaught exception, <tt>std::terminate()</tt> shall be called.</del> 11969<ins>If the evaluation of <tt><i>INVOKE</i>(g, wi...)</tt> terminates 11970with an uncaught exception, <tt>std::terminate()</tt> shall be called [<i>Note:</i> 11971<tt>std::terminate()</tt> could be called before entering <tt>g</tt>. -- <i>end note</i>]. Any 11972exception thrown before the evaluation of <tt><i>INVOKE</i></tt> has started shall be 11973catchable in the calling thread.</ins> 11974</p> 11975</blockquote> 11976</blockquote> 11977 11978<p> 11979Text referring to when <tt>terminate()</tt> is called was contributed by Ganesh. 11980</p> 11981 11982</blockquote> 11983 11984<p><i>[ 11985Batavia (2009-05): 11986]</i></p> 11987 11988<blockquote> 11989We agree with the proposed resolution, 11990but would like the final sentence to be reworded 11991since "catchable" is not a term of art (and is used nowhere else). 11992</blockquote> 11993 11994<p><i>[ 119952009-07 Frankfurt: 11996]</i></p> 11997 11998 11999<blockquote> 12000<p> 12001This is linked to 12002<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2901.pdf">N2901</a>. 12003</p> 12004<p> 12005Howard to open a separate issue to remove (<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1176">1176</a>). 12006</p> 12007<p> 12008In Frankfurt there is no consensus for removing the variadic constructor. 12009</p> 12010</blockquote> 12011 12012<p><i>[ 120132009-10 Santa Cruz: 12014]</i></p> 12015 12016 12017<blockquote> 12018We want to move forward with this issue. If we later take it out via <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1176">1176</a> 12019then that's ok too. Needs small group to improve wording. 12020</blockquote> 12021 12022<p><i>[ 120232009-10 Santa Cruz: 12024]</i></p> 12025 12026 12027<blockquote> 12028<p> 12029Stefanus provided revised wording. Moved to Review Here is the original wording: 12030</p> 12031<blockquote> 12032<p> 12033Modify the class definition of <tt>std::thread</tt> in 30.3.1 [thread.thread.class] to remove the 12034following signature: 12035</p> 12036 12037<blockquote><pre><del>template<class F> explicit thread(F f);</del> 12038template<class F, class ... Args> <ins>explicit</ins> thread(F&& f, Args&& ... args); 12039</pre></blockquote> 12040 12041<p> 12042Modify 30.3.1.2 [thread.thread.constr] to replace the constructors prior to paragraph 4 with 12043the single constructor as above. Replace paragraph 4 - 6 with the 12044following: 12045</p> 12046 12047<blockquote> 12048<p> 12049-4- <i>Requires:</i> <tt>F</tt> and each <tt>Ti</tt> in <tt>Args</tt> shall be <del><tt>CopyConstructible</tt> 12050if an lvalue and otherwise</del> <tt>MoveConstructible</tt>. 12051<tt><i>INVOKE</i>(f, w1, w2, ..., wN)</tt> (20.7.2 [func.require]) shall be a valid expression for 12052some values <tt>w1, w2, ... , wN,</tt> where <tt>N == sizeof...(Args)</tt>. 12053</p> 12054<p> 12055-5- <i>Effects:</i> Constructs an object of type <tt>thread</tt> 12056<del>and executes <tt><i>INVOKE</i>(f, t1, t2, ..., tN)</tt> in a new 12057thread of execution, where <tt>t1, t2, ..., tN</tt> are the values in <tt>args...</tt></del>. 12058<ins>Constructs 12059the following objects:</ins> 12060</p> 12061<blockquote><pre><ins>typename decay<F>::type g(std::forward<F>(f));</ins> 12062<ins>tuple<typename decay<Args>::type...> w(std::forward<Args>(args)...);</ins> 12063</pre></blockquote> 12064<p> 12065<ins>and executes <tt><i>INVOKE</i>(g, wi...)</tt> in a new thread of execution. 12066These objects shall be destroyed when the new thread of execution completes.</ins> 12067Any return value from <tt>g</tt> is ignored. 12068<del>If <tt>f</tt> terminates with an uncaught exception, <tt>std::terminate()</tt> shall be called.</del> 12069<ins>If the evaluation of <tt><i>INVOKE</i>(g, wi...)</tt> terminates 12070with an uncaught exception, <tt>std::terminate()</tt> shall be called [<i>Note:</i> 12071<tt>std::terminate()</tt> could be called before entering <tt>g</tt>. -- <i>end note</i>]. Any 12072exception thrown before the evaluation of <tt><i>INVOKE</i></tt> has started shall be 12073catchable in the calling thread.</ins> 12074</p> 12075<p> 12076-6- <i>Synchronization:</i> The invocation of the constructor <i>happens before</i> the 12077invocation of <del><tt>f</tt></del> <ins><tt>g</tt></ins>. 12078</p> 12079</blockquote> 12080 12081</blockquote> 12082</blockquote> 12083 12084 12085<p><b>Proposed resolution:</b></p> 12086<p> 12087Modify the class definition of <tt>std::thread</tt> in 30.3.1 [thread.thread.class] to remove the 12088following signature: 12089</p> 12090 12091<blockquote><pre><del>template<class F> explicit thread(F f);</del> 12092template<class F, class ... Args> <ins>explicit</ins> thread(F&& f, Args&& ... args); 12093</pre></blockquote> 12094 12095<p> 12096Modify 30.3.1.2 [thread.thread.constr] to replace the constructors prior to paragraph 4 with 12097the single constructor as above. Replace paragraph 4 - 6 with the 12098following: 12099</p> 12100 12101<blockquote> 12102<p> 12103-4- <i>Requires:</i> <tt>F</tt> and each <tt>Ti</tt> in <tt>Args</tt> 12104shall be <del><tt>CopyConstructible</tt> if an lvalue and 12105otherwise</del> <tt>MoveConstructible</tt>. <tt><i>INVOKE</i>(f, w1, w2, 12106..., wN)</tt> (20.7.2 [func.require]) shall be a valid expression 12107for some values <tt>w1, w2, ... , wN,</tt> where <tt>N == 12108sizeof...(Args)</tt>. 12109</p> 12110 12111<p> 12112-5- <i>Effects:</i> Constructs an object of type <tt>thread</tt> <del>and executes 12113<tt>INVOKE(f, t1, t2, ..., tN)</tt> in a new thread of execution, where 12114<tt>t1, t2, ..., tN</tt> are the values in <tt>args...</tt></del>. 12115<ins>Given a function as follows:</ins> 12116<del>Any return 12117value from <tt>f</tt> is ignored. If <tt>f</tt> terminates with an 12118uncaught exception, <tt>std::terminate()</tt> shall be called.</del> 12119</p> 12120 12121<blockquote><pre><ins> 12122template<typename T> typename decay<T>::type decay_copy(T&& v) 12123 { return std::forward<T>(v); } 12124</ins></pre></blockquote> 12125 12126<p><ins> 12127The new thread of execution executes <tt>INVOKE(decay_copy(f), 12128decay_copy(args)...)</tt> with the calls to <tt>decay_copy()</tt> being evaluated in 12129the constructing thread. Any return value from this invocation is 12130ignored. [<i>Note:</i> this implies any exceptions not thrown from the 12131invocation of the copy of <tt>f</tt> will be thrown in the constructing thread, 12132not the new thread. — <i>end note</i>]. 12133</ins></p> 12134 12135<p> 12136-6- <i>Synchronization:</i> The invocation of the constructor <i>happens before</i> the 12137invocation of <ins>copy of</ins> <tt>f</tt>. 12138</p> 12139</blockquote> 12140 12141 12142 12143 12144 12145 12146<hr> 12147<h3><a name="932"></a>932. <tt>unique_ptr(pointer p)</tt> for pointer deleter types</h3> 12148<p><b>Section:</b> 20.8.14.2.1 [unique.ptr.single.ctor] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 12149 <b>Submitter:</b> Howard Hinnant <b>Opened:</b> 2008-11-26 <b>Last modified:</b> 2009-10-22</p> 12150<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#unique.ptr.single.ctor">active issues</a> in [unique.ptr.single.ctor].</p> 12151<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#unique.ptr.single.ctor">issues</a> in [unique.ptr.single.ctor].</p> 12152<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 12153<p><b>Discussion:</b></p> 12154 12155<p><b>Addresses US 79</b></p> 12156 12157<p> 1215820.8.14.2.1 [unique.ptr.single.ctor]/5 no longer requires for <tt>D</tt> 12159not to be a pointer type. I believe this restriction was accidently removed 12160when we relaxed the completeness reuqirements on <tt>T</tt>. The restriction 12161needs to be put back in. Otherwise we have a run time failure that could 12162have been caught at compile time: 12163</p> 12164 12165<blockquote><pre>{ 12166unique_ptr<int, void(*)(void*)> p1(malloc(sizeof(int))); <font color="#c80000">// should not compile</font> 12167} <font color="#c80000">// p1.~unique_ptr() dereferences a null function pointer</font> 12168unique_ptr<int, void(*)(void*)> p2(malloc(sizeof(int)), free); <font color="#c80000">// ok</font> 12169</pre></blockquote> 12170 12171<p><i>[ 12172Post Summit: 12173]</i></p> 12174 12175 12176<blockquote> 12177Recommend Tentatively Ready. 12178</blockquote> 12179 12180<p><i>[ 121812009-07 Frankfurt 12182]</i></p> 12183 12184 12185<blockquote> 12186Moved from Tentatively Ready to Open only because the wording needs to be 12187improved for enable_if type constraining, possibly following Robert's 12188formula. 12189</blockquote> 12190 12191<p><i>[ 121922009-07 Frankfurt: 12193]</i></p> 12194 12195 12196<blockquote> 12197<p> 12198We need to consider whether some requirements in the Requires paragraphs 12199of [unique.ptr] should instead be Remarks. 12200</p> 12201<p> 12202Leave Open. Howard to provide wording, and possibly demonstrate how this 12203can be implemented using enable_if. 12204</p> 12205</blockquote> 12206 12207<p><i>[ 122082009-07-27 Howard adds: 12209]</i></p> 12210 12211 12212<blockquote> 12213<p> 12214The two constructors to which this issue applies are not easily constrained 12215with <tt>enable_if</tt> as they are not templated: 12216</p> 12217 12218<blockquote><pre>unique_ptr(); 12219explicit unique_ptr(pointer p); 12220</pre></blockquote> 12221 12222<p> 12223To "SFINAE" these constructors away would take heroic effort such as specializing 12224the entire <tt>unique_ptr</tt> class template on pointer deleter types. There 12225is insufficient motivation for such heroics. Here is the expected and 12226reasonable implementation for these constructors: 12227</p> 12228 12229<blockquote><pre>unique_ptr() 12230 : ptr_(pointer()) 12231 { 12232 static_assert(!is_pointer<deleter_type>::value, 12233 "unique_ptr constructed with null function pointer deleter"); 12234 } 12235explicit unique_ptr(pointer p) 12236 : ptr_(p) 12237 { 12238 static_assert(!is_pointer<deleter_type>::value, 12239 "unique_ptr constructed with null function pointer deleter"); 12240 } 12241</pre></blockquote> 12242 12243<p> 12244I.e. just use <tt>static_assert</tt> to verify that the constructor is not 12245instantiated with a function pointer for a deleter. The compiler will automatically 12246take care of issuing a diagnostic if the deleter is a reference type (uninitialized 12247reference error). 12248</p> 12249 12250<p> 12251In keeping with our discussions in Frankfurt, I'm moving this requirement on 12252the implementation from the Requires paragraph to a Remarks paragraph. 12253</p> 12254 12255</blockquote> 12256 12257<p><i>[ 122582009-08-17 Daniel adds: 12259]</i></p> 12260 12261 12262<blockquote> 12263<p> 12264It is insufficient to require a diagnostic. This doesn't imply an 12265ill-formed program 12266as of 1.3.3 [defns.diagnostic] (a typical alternative would be a compiler 12267warning), but 12268exactly that seems to be the intend. I suggest to use the following 12269remark instead: 12270</p> 12271 12272<blockquote> 12273<i>Remarks:</i> The program shall be ill-formed if this constructor is 12274instantiated when <tt>D</tt> is a pointer type or reference type. 12275</blockquote> 12276 12277<p> 12278Via the general standard rules of 1.4 [intro.compliance] the "diagnostic 12279required" is implied. 12280</p> 12281 12282</blockquote> 12283 12284<p><i>[ 122852009-10 Santa Cruz: 12286]</i></p> 12287 12288 12289<blockquote> 12290Moved to Ready. 12291</blockquote> 12292 12293 12294 12295<p><b>Proposed resolution:</b></p> 12296<p> 12297Change the description of the default constructor in 20.8.14.2.1 [unique.ptr.single.ctor]: 12298</p> 12299 12300<blockquote><pre>unique_ptr(); 12301</pre> 12302<blockquote> 12303<p> 12304-1- <i>Requires:</i> <tt>D</tt> shall be default constructible, and that construction 12305shall not throw an exception. <del><tt>D</tt> shall 12306not be a reference type or pointer type (diagnostic required).</del> 12307</p> 12308<p>...</p> 12309<p><ins> 12310<i>Remarks:</i> The program shall be ill-formed if this constructor is 12311instantiated when <tt>D</tt> is a pointer type or reference type. 12312 12313</ins></p> 12314</blockquote> 12315</blockquote> 12316 12317<p> 12318Add after 20.8.14.2.1 [unique.ptr.single.ctor]/8: 12319</p> 12320 12321<blockquote><pre>unique_ptr(pointer p); 12322</pre> 12323<blockquote> 12324<p>...</p> 12325<p><ins> 12326<i>Remarks:</i> The program shall be ill-formed if this constructor is 12327instantiated when <tt>D</tt> is a pointer type or reference type. 12328 12329</ins></p> 12330</blockquote> 12331</blockquote> 12332 12333 12334 12335 12336 12337<hr> 12338<h3><a name="939"></a>939. Problem with <tt>std::identity</tt> and reference-to-temporaries</h3> 12339<p><b>Section:</b> 20.3.3 [forward] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 12340 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2008-12-11 <b>Last modified:</b> 2009-10-29</p> 12341<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#forward">issues</a> in [forward].</p> 12342<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 12343<p><b>Discussion:</b></p> 12344<p> 12345<tt>std::identity</tt> takes an argument of type <tt>T const &</tt> 12346and returns a result of <tt>T const &</tt>. 12347</p> 12348<p> 12349Unfortunately, this signature will accept a value of type other than <tt>T</tt> that 12350is convertible-to-<tt>T</tt>, and then return a reference to the dead temporary. The 12351constraint in the concepts version simply protects against returning 12352reference-to-<tt>void</tt>. 12353</p> 12354<p> 12355Solutions: 12356</p> 12357<blockquote> 12358<p> 12359i/ Return-by-value, potentially slicing bases and rejecting non-copyable 12360types 12361</p> 12362<p> 12363ii/ Provide an additional overload: 12364</p> 12365<blockquote><pre>template< typename T > 12366template operator( U & ) = delete; 12367</pre></blockquote> 12368<p> 12369This seems closer on intent, but moves beyond the original motivation for 12370the operator, which is compatibility with existing (non-standard) 12371implementations. 12372</p> 12373<p> 12374iii/ Remove the <tt>operator()</tt> overload. This restores the original definition 12375of the <tt>identity</tt>, although now effectively a type_trait rather than part of 12376the perfect forwarding protocol. 12377</p> 12378<p> 12379iv/ Remove <tt>std::identity</tt> completely; its original reason to exist is 12380replaced with the <tt>IdentityOf</tt> concept. 12381</p> 12382</blockquote> 12383<p> 12384My own preference is somewhere between (ii) and (iii) - although I stumbled 12385over the issue with a specific application hoping for resolution (i)! 12386</p> 12387 12388<p><i>[ 12389Batavia (2009-05): 12390]</i></p> 12391 12392<blockquote> 12393<p> 12394We dislike options i and iii, and option ii seems like overkill. 12395If we remove it (option iv), implementers can still provide it under a 12396different name. 12397</p> 12398<p> 12399Move to Open pending wording (from Alisdair) for option iv. 12400</p> 12401</blockquote> 12402 12403<p><i>[ 124042009-05-23 Alisdair provided wording for option iv. 12405]</i></p> 12406 12407 12408<p><i>[ 124092009-07-20 Alisdair adds: 12410]</i></p> 12411 12412 12413<blockquote> 12414<p> 12415I'm not sure why this issue was not discussed at Frankfurt (or I missed 12416the discussion) but the rationale is now fundamentally flawed. With the 12417removal of concepts, <tt>std::identity</tt> again becomes an important library 12418type so we cannot simply remove it. 12419</p> 12420<p> 12421At that point, we need to pick one of the other suggested resolutions, 12422but have no guidance at the moment. 12423</p> 12424</blockquote> 12425 12426<p><i>[ 124272009-07-20 Howard adds: 12428]</i></p> 12429 12430 12431<blockquote> 12432<p> 12433I believe the rationale for not addressing this issue in Frankfurt was that it did 12434not address a national body comment. 12435</p> 12436<p> 12437I also believe that removal of <tt>identity</tt> is still a practical option as 12438my latest reformulation of <tt>forward</tt>, which is due to comments suggested 12439at Summit, no longer uses <tt>identity</tt>. :-) 12440</p> 12441 12442<blockquote><pre>template <class T, class U, 12443 class = typename enable_if 12444 < 12445 !is_lvalue_reference<T>::value || 12446 is_lvalue_reference<T>::value && 12447 is_lvalue_reference<U>::value 12448 >::type, 12449 class = typename enable_if 12450 < 12451 is_same<typename remove_all<T>::type, 12452 typename remove_all<U>::type>::value 12453 >::type> 12454inline 12455T&& 12456forward(U&& t) 12457{ 12458 return static_cast<T&&>(t); 12459 12460} 12461</pre> 12462 12463<p><i>[ 12464The above code assumes acceptance of <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1120">1120</a> for the definition of 12465<tt>remove_all</tt>. This is just to make the syntax a little more palatable. 12466Without this trait the above is still very implementable. 12467]</i></p> 12468 12469 12470</blockquote> 12471 12472<p> 12473Paper with rationale is on the way ... <i>really</i>, I promise this time! ;-) 12474</p> 12475</blockquote> 12476 12477<p><i>[ 124782009-07-30 Daniel adds: See <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#823">823</a> for an alternative resolution. 12479]</i></p> 12480 12481 12482<p><i>[ 124832009-10 Santa Cruz: 12484]</i></p> 12485 12486 12487<blockquote> 12488Move to Ready. Howard will update proposed wording to reflect current draft. 12489</blockquote> 12490 12491 12492 12493<p><b>Proposed resolution:</b></p> 12494<p> 12495Strike from 20.3 [utility]: 12496</p> 12497 12498<blockquote><pre><del>template <class T> struct identity;</del> 12499</pre></blockquote> 12500 12501<p> 12502Remove from 20.3.3 [forward]: 12503</p> 12504 12505<blockquote> 12506<pre><del>template <class T> struct identity { 12507 typedef T type; 12508 12509 const T& operator()(const T& x) const; 12510};</del> 12511 12512<del>const T& operator()(const T& x) const;</del> 12513</pre> 12514<blockquote> 12515<del>-2- <i>Returns:</i> <tt>x</tt></del> 12516</blockquote> 12517</blockquote> 12518 12519 12520 12521 12522 12523 12524<hr> 12525<h3><a name="940"></a>940. <tt>std::distance</tt></h3> 12526<p><b>Section:</b> 24.4.4 [iterator.operations] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 12527 <b>Submitter:</b> Thomas <b>Opened:</b> 2008-12-14 <b>Last modified:</b> 2009-10-22</p> 12528<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#iterator.operations">active issues</a> in [iterator.operations].</p> 12529<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#iterator.operations">issues</a> in [iterator.operations].</p> 12530<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 12531<p><b>Discussion:</b></p> 12532 12533<p><b>Addresses UK 270</b></p> 12534 12535<p> 12536Regarding the <tt>std::distance</tt> - function, 24.4.4 [iterator.operations] 12537/ 4 says: 12538</p> 12539<blockquote> 12540Returns the 12541number of increments or decrements needed to get from first to last. 12542</blockquote> 12543<p> 12544This sentence is completely silent about the sign of the return value. 1254524.4.4 [iterator.operations] / 1 gives more information about the 12546underlying operations, but 12547again no inferences about the sign can be made. 12548Strictly speaking, that is taking that sentence literally, I think this 12549sentence even implies a positive return value in all cases, as the 12550number of increments or decrements is clearly a ratio scale variable, 12551with a natural zero bound. 12552</p> 12553<p> 12554Practically speaking, my implementations did what common sense and 12555knowledge based on pointer arithmetic forecasts, namely a positive sign 12556for increments (that is, going from <tt>first</tt> to <tt>last</tt> by <tt>operator++</tt>), and a 12557negative sign for decrements (going from <tt>first</tt> to <tt>last</tt> by <tt>operator--</tt>). 12558</p> 12559<p> 12560Here are my two questions: 12561</p> 12562<p> 12563First, is that paragraph supposed to be interpreted in the way what I 12564called 'common sense', that is negative sign for decrements ? I am 12565fairly sure that's the supposed behavior, but a double-check here in 12566this group can't hurt. 12567</p> 12568<p> 12569Second, is the present wording (2003 standard version - no idea about 12570the draft for the upcoming standard) worth an edit to make it a bit more 12571sensible, to mention the sign of the return value explicitly ? 12572</p> 12573 12574<p><i>[ 12575Daniel adds: 12576]</i></p> 12577 12578 12579<blockquote> 12580<p> 12581My first thought was that resolution <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#204">204</a> would already cover the 12582issue report, but it seems that current normative wording is in 12583contradiction to that resolution: 12584</p> 12585 12586<p> 12587Referring to 12588<a href="" ref="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2798.pdf">N2798</a>, 1258924.4.4 [iterator.operations]/ p.4 says: 12590</p> 12591 12592<blockquote> 12593<i>Effects:</i> Returns the number of increments or decrements needed to get 12594from <tt>first</tt> to <tt>last</tt>. 12595</blockquote> 12596 12597<p> 12598IMO the part " or decrements" is in contradiction to p. 5 which says 12599</p> 12600 12601<blockquote> 12602<i>Requires:</i> <tt>last</tt> shall be reachable from <tt>first</tt>. 12603</blockquote> 12604 12605<p> 12606because "reachable" is defined in X [iterator.concepts]/7 as 12607</p> 12608 12609<blockquote> 12610An iterator <tt>j</tt> is called reachable from an iterator <tt>i</tt> if and only if 12611there is a finite 12612sequence of applications of the expression <tt>++i</tt> that makes <tt>i == j</tt>.[..] 12613</blockquote> 12614 12615<p> 12616Here is wording that would be consistent with this definition of "reachable": 12617</p> 12618 12619<p> 12620Change 24.4.4 [iterator.operations] p4 as follows: 12621</p> 12622 12623<blockquote> 12624<i>Effects:</i> Returns the number of increments <del>or decrements</del> 12625needed to get from <tt>first</tt> to <tt>last</tt>. 12626</blockquote> 12627 12628</blockquote> 12629 12630<p> 12631Thomas adds more discussion and an alternative view point 12632<a href="http://groups.google.com/group/comp.std.c++/browse_thread/thread/e8e46dcda0a5d797#">here</a>. 12633</p> 12634 12635<p><i>[ 12636Summit: 12637]</i></p> 12638 12639 12640<blockquote> 12641The proposed wording below was verbally agreed to. Howard provided. 12642</blockquote> 12643 12644<p><i>[ 12645Batavia (2009-05): 12646]</i></p> 12647 12648<blockquote> 12649<p> 12650Pete reports that a recent similar change has been made 12651for the <tt>advance()</tt> function. 12652</p> 12653<p> 12654We agree with the proposed resolution. 12655Move to Tentatively Ready. 12656</p> 12657</blockquote> 12658 12659<p><i>[ 126602009-07 Frankfurt 12661]</i></p> 12662 12663 12664<blockquote> 12665Moved from Tentatively Ready to Open only because the wording needs to be 12666tweaked for concepts removal. 12667</blockquote> 12668 12669<p><i>[ 126702009-07 Frankfurt: 12671]</i></p> 12672 12673 12674<blockquote> 12675Leave Open pending arrival of a post-Concepts WD. 12676</blockquote> 12677 12678<p><i>[ 126792009-10-14 Daniel provided de-conceptified wording. 12680]</i></p> 12681 12682 12683<p><i>[ 126842009-10 Santa Cruz: 12685]</i></p> 12686 12687 12688<blockquote> 12689Move to Ready, replacing the Effects clause in the proposed wording with 12690"If InputIterator meets the requirements of random access iterator then 12691returns (last - first), otherwise returns the number of increments 12692needed to get from first to list.". 12693</blockquote> 12694 12695 12696 12697<p><b>Proposed resolution:</b></p> 12698<ol> 12699<li> 12700<p> 12701Change 24.2.5 [random.access.iterators], Table 105 as indicated [This change is not 12702essential but it simplifies the specification] for the row with 12703expression "<tt>b - a</tt>" 12704and the column Operational semantics: 12705</p> 12706 12707<blockquote><pre><del>(a < b) ? </del>distance(a,b) 12708<del>: -distance(b,a)</del> 12709</pre></blockquote> 12710</li> 12711 12712<li> 12713<p> 12714Change 24.4.4 [iterator.operations]/4+5 as indicated: 12715</p> 12716 12717<blockquote><pre>template<class InputIterator> 12718 typename iterator_traits<InputIterator>::difference_type 12719 distance(InputIterator first, InputIterator last); 12720</pre> 12721<blockquote> 12722<p> 127234 <i>Effects:</i> <ins>If <tt>InputIterator</tt> meets the requirements 12724of random access iterator then returns <tt>(last - first)</tt>, 12725otherwise</ins> <del>R</del><ins>r</ins>eturns the number of increments 12726<del>or decrements</del> needed to get from <tt>first</tt> to 12727<tt>last</tt>. 12728</p> 12729 12730<p> 127315 <i>Requires:</i> <ins>If <tt>InputIterator</tt> meets the requirements 12732of random access iterator then <tt>last</tt> shall be reachable from 12733<tt>first</tt> or <tt>first</tt> shall be reachable from <tt>last</tt>, 12734otherwise</ins> <tt>last</tt> shall be reachable from <tt>first</tt>. 12735</p> 12736</blockquote> 12737</blockquote> 12738</li> 12739</ol> 12740 12741 12742 12743 12744 12745 12746 12747 12748 12749<hr> 12750<h3><a name="950"></a>950. unique_ptr converting ctor shouldn't accept array form</h3> 12751<p><b>Section:</b> 20.8.14.2.1 [unique.ptr.single.ctor] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 12752 <b>Submitter:</b> Howard Hinnant <b>Opened:</b> 2009-01-07 <b>Last modified:</b> 2009-10-21</p> 12753<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#unique.ptr.single.ctor">active issues</a> in [unique.ptr.single.ctor].</p> 12754<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#unique.ptr.single.ctor">issues</a> in [unique.ptr.single.ctor].</p> 12755<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 12756<p><b>Discussion:</b></p> 12757<p> 12758<tt>unique_ptr</tt>'s of array type should not convert to 12759<tt>unique_ptr</tt>'s which do not have an array type. 12760</p> 12761 12762<blockquote><pre>struct Deleter 12763{ 12764 void operator()(void*) {} 12765}; 12766 12767int main() 12768{ 12769 unique_ptr<int[], Deleter> s; 12770 unique_ptr<int, Deleter> s2(std::move(s)); <font color="#c80000">// should not compile</font> 12771} 12772</pre></blockquote> 12773 12774<p><i>[ 12775Post Summit: 12776]</i></p> 12777 12778 12779<blockquote> 12780<p> 12781Walter: Does the "diagnostic required" apply to both arms of the "and"? 12782</p> 12783<p> 12784Tom Plum: suggest to break into several sentences 12785</p> 12786<p> 12787Walter: suggest "comma" before the "and" in both places 12788</p> 12789<p> 12790Recommend Review. 12791</p> 12792</blockquote> 12793 12794<p><i>[ 12795Batavia (2009-05): 12796]</i></p> 12797 12798<blockquote> 12799The post-Summit comments have been applied to the proposed resolution. 12800We now agree with the proposed resolution. 12801Move to Tentatively Ready. 12802</blockquote> 12803 12804<p><i>[ 128052009-07 Frankfurt 12806]</i></p> 12807 12808 12809<blockquote> 12810Moved from Tentatively Ready to Open only because the wording needs to be 12811improved for enable_if type constraining, possibly following Robert's 12812formula. 12813</blockquote> 12814 12815<p><i>[ 128162009-08-01 Howard updates wording and sets to Review. 12817]</i></p> 12818 12819 12820<p><i>[ 128212009-10 Santa Cruz: 12822]</i></p> 12823 12824 12825<blockquote> 12826Move to Ready. 12827</blockquote> 12828 12829 12830 12831<p><b>Proposed resolution:</b></p> 12832<p> 12833Change 20.8.14.2.1 [unique.ptr.single.ctor]: 12834</p> 12835 12836<blockquote> 12837<pre>template <class U, class E> unique_ptr(unique_ptr<U, E>&& u); 12838</pre> 12839<blockquote> 12840<p> 12841-20- <i>Requires:</i> If <tt>D</tt> is not a reference type, 12842construction of the deleter <tt>D</tt> from an rvalue of type <tt>E</tt> 12843shall be well formed and shall not throw an exception. <del>If <tt>D</tt> is 12844a reference type, then <tt>E</tt> shall be the same type as <tt>D</tt> 12845(diagnostic required). <tt>unique_ptr<U, E>::pointer</tt> shall be 12846implicitly convertible to <tt>pointer</tt>. [<i>Note:</i> These requirements 12847imply that <tt>T</tt> and <tt>U</tt> are complete types. — <i>end note</i>]</del> 12848</p> 12849 12850<p><ins> 12851<i>Remarks:</i> If <tt>D</tt> is 12852a reference type, then <tt>E</tt> shall be the same type as <tt>D</tt>, else this 12853constructor shall not participate in overload resolution. <tt>unique_ptr<U, E>::pointer</tt> shall be 12854implicitly convertible to <tt>pointer</tt>, else this 12855constructor shall not participate in overload resolution. <tt>U</tt> shall not be 12856an array type, else this 12857constructor shall not participate in overload resolution. [<i>Note:</i> These requirements 12858imply that <tt>T</tt> and <tt>U</tt> are complete types. — <i>end note</i>] 12859</ins></p> 12860 12861</blockquote> 12862</blockquote> 12863 12864<p> 12865Change 20.8.14.2.3 [unique.ptr.single.asgn]: 12866</p> 12867 12868<blockquote> 12869<pre>template <class U, class E> unique_ptr& operator=(unique_ptr<U, E>&& u); 12870</pre> 12871<blockquote> 12872<p> 12873-6- <i>Requires:</i> Assignment of the deleter <tt>D</tt> from an rvalue 12874<tt>D</tt> shall not throw an exception. <del><tt>unique_ptr<U, 12875E>::pointer</tt> shall be implicitly convertible to <tt>pointer</tt>. 12876[<i>Note:</i> These requirements imply that <tt>T</tt> and <tt>U</tt> 12877are complete types. — <i>end note</i>]</del> 12878</p> 12879 12880<p><ins> 12881<i>Remarks:</i> <tt>unique_ptr<U, 12882E>::pointer</tt> shall be implicitly convertible to <tt>pointer</tt>, else this 12883operator shall not participate in overload resolution. 12884<tt>U</tt> shall not be an array type, else this 12885operator shall not participate in overload resolution. 12886[<i>Note:</i> These requirements imply that <tt>T</tt> and <tt>U</tt> 12887are complete types. — <i>end note</i>] 12888</ins></p> 12889 12890</blockquote> 12891</blockquote> 12892 12893 12894 12895 12896 12897 12898<hr> 12899<h3><a name="951"></a>951. Various threading bugs #1</h3> 12900<p><b>Section:</b> 20.9.2.1 [time.traits.is_fp] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 12901 <b>Submitter:</b> Pete Becker <b>Opened:</b> 2009-01-07 <b>Last modified:</b> 2009-10-23</p> 12902<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 12903<p><b>Discussion:</b></p> 12904 12905<p> 12906Related to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#953">953</a>. 12907</p> 12908 12909<p> 1291020.9.2.1 [time.traits.is_fp] says that the type <tt>Rep</tt> "is 12911assumed to be ... a class emulating an integral type." What are the 12912requirements for such a type? 12913</p> 12914<p><i>[ 129152009-05-10 Howard adds: 12916]</i></p> 12917 12918 12919<blockquote> 12920<tt>IntegralLike</tt>. 12921</blockquote> 12922 12923<p><i>[ 12924Batavia (2009-05): 12925]</i></p> 12926 12927<blockquote> 12928<p> 12929As with issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#953">953</a>, 12930we recommend this issue be addressed in the context of providing concepts for the entire <tt>thread</tt> header. 12931</p> 12932<p> 12933We look forward to proposed wording. 12934</p> 12935<p> 12936Move to Open. 12937</p> 12938</blockquote> 12939 12940<p><i>[ 129412009-08-01 Howard adds: 12942]</i></p> 12943 12944 12945<blockquote> 12946<p> 12947I have surveyed all clauses of 20.9.2.2 [time.traits.duration_values], 1294820.9.2.3 [time.traits.specializations] and 20.9.3 [time.duration]. 12949I can not find any clause which involves the use of a <tt>duration::rep</tt> type 12950where the requirements on the <tt>rep</tt> type are not clearly spelled out. 12951These requirements were carefully crafted to allow any arithmetic type, or 12952any user-defined type emulating an arithmetic type. 12953</p> 12954 12955<p> 12956Indeed, <tt>treat_as_floating_point</tt> 12957becomes completely superfluous if <tt>duration::rep</tt> can never be a class type. 12958</p> 12959 12960<p> 12961There will be some <tt>Rep</tt> types which will not meet the requirements of 12962<em>every</em> <tt>duration</tt> operation. This is no different than the fact 12963that <tt>vector<T></tt> can easily be used for types <tt>T</tt> which are 12964not <tt>DefaultConstructible</tt>, even though some members of <tt>vector<T></tt> 12965require <tt>T</tt> to be <tt>DefaultConstructible</tt>. This is why the requirements 12966on <tt>Rep</tt> are specified for each operation individually. 12967</p> 12968 12969<p> 12970In 20.9.2.1 [time.traits.is_fp] p1: 12971</p> 12972 12973<blockquote><pre>template <class Rep> struct treat_as_floating_point 12974 : is_floating_point<Rep> { }; 12975</pre> 12976 12977<blockquote> 12978The <tt>duration</tt> template uses the <tt>treat_as_floating_point</tt> trait to help 12979determine if a <tt>duration</tt> object can be converted to another <tt>duration</tt> 12980with a different tick period. If <tt>treat_as_floating_point<Rep>::value</tt> is 12981<tt>true</tt>, then <tt>Rep</tt> is a floating-point type and implicit conversions are 12982allowed among <tt>duration</tt>s. Otherwise, the implicit convertibility depends 12983on the tick periods of the <tt>duration</tt>s. If <tt>Rep</tt> is <u>a class type which 12984emulates a floating-point type</u>, the author of <tt>Rep</tt> can specialize 12985<tt>treat_as_floating_point</tt> so that <tt>duration</tt> will treat this <tt>Rep</tt> as if it 12986were a floating-point type. Otherwise <tt>Rep</tt> is assumed to be an integral 12987type or <u>a class emulating an integral type</u>. 12988</blockquote> 12989</blockquote> 12990 12991<p> 12992The phrases "a class type which emulates a floating-point type" and 12993"a class emulating an integral type" are clarifying phrases which refer to 12994the summation of all the requirements on the <tt>Rep</tt> type specified in 12995detail elsewhere (and <em>should not</em> be repeated here). 12996</p> 12997 12998<p> 12999This specification has been implemented, now multiple times, and the experience 13000has been favorable. The current specification clearly specifies the requirements 13001at each point of use (though I'd be happy to fix any place I may have missed, 13002but none has been pointed out). 13003</p> 13004 13005<p> 13006I am amenable to improved wording of this paragraph (and any others), but do not have any 13007suggestions for improved wording at this time. I am <em>strongly</em> opposed to 13008changes which would significantly alter the semantics of the 13009specification under 20.9 [time] without firmly grounded and 13010documented rationale, example implementation, testing, and user 13011experience which relates a positive experience. 13012</p> 13013 13014<p> 13015I recommend NAD unless someone wants to produce some clarifying wording. 13016</p> 13017</blockquote> 13018 13019<p><i>[ 130202009-10 Santa Cruz: 13021]</i></p> 13022 13023 13024<blockquote> 13025Stefanus to provide wording to turn this into a note. 13026</blockquote> 13027 13028 13029 13030<p><b>Proposed resolution:</b></p> 13031<p> 13032</p> 13033 13034 13035 13036 13037 13038<hr> 13039<h3><a name="953"></a>953. Various threading bugs #3</h3> 13040<p><b>Section:</b> 20.9.1 [time.clock.req] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 13041 <b>Submitter:</b> Pete Becker <b>Opened:</b> 2009-01-07 <b>Last modified:</b> 2009-10-23</p> 13042<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#time.clock.req">active issues</a> in [time.clock.req].</p> 13043<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#time.clock.req">issues</a> in [time.clock.req].</p> 13044<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 13045<p><b>Discussion:</b></p> 13046 13047<p> 13048Related to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#951">951</a>. 13049</p> 13050 13051<p> 1305220.9.1 [time.clock.req] says that a clock's <tt>rep</tt> member is "an 13053arithmetic type or a class emulating an arithmetic type." What are the 13054requirements for such a type? 13055</p> 13056 13057<p><i>[ 130582009-05-10 Howard adds: 13059]</i></p> 13060 13061 13062<blockquote> 13063This wording was aimed directly at the <tt>ArithmeticLike</tt> concept. 13064</blockquote> 13065 13066<p><i>[ 13067Batavia (2009-05): 13068]</i></p> 13069 13070<blockquote> 13071<p> 13072We recommend this issue be addressed in the context of providing concepts 13073for the entire <tt>thread</tt> header. 13074</p> 13075<p> 13076May resolve for now by specifying arithmetic types, 13077and in future change to <tt>ArithmeticLike</tt>. 13078However, Alisdair believes this is not feasible. 13079</p> 13080<p> 13081Bill disagrees. 13082</p> 13083<p> 13084We look forward to proposed wording. Move to Open. 13085</p> 13086</blockquote> 13087 13088<p><i>[ 130892009-08-01 Howard adds: 13090]</i></p> 13091 13092 13093<blockquote> 13094See commented dated 2009-08-01 in <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#951">951</a>. 13095</blockquote> 13096 13097<p><i>[ 130982009-10 Santa Cruz: 13099]</i></p> 13100 13101 13102<blockquote> 13103Stefanus to provide wording to turn this into a note. 13104</blockquote> 13105 13106 13107 13108<p><b>Proposed resolution:</b></p> 13109<p> 13110</p> 13111 13112 13113 13114 13115 13116<hr> 13117<h3><a name="954"></a>954. Various threading bugs #4</h3> 13118<p><b>Section:</b> 20.9.1 [time.clock.req] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 13119 <b>Submitter:</b> Pete Becker <b>Opened:</b> 2009-01-07 <b>Last modified:</b> 2009-10-21</p> 13120<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#time.clock.req">active issues</a> in [time.clock.req].</p> 13121<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#time.clock.req">issues</a> in [time.clock.req].</p> 13122<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 13123<p><b>Discussion:</b></p> 13124<p> 13125Table 55 -- Clock Requirements (in 20.9.1 [time.clock.req]) 13126</p> 13127 13128<ol type="a"> 13129<li> 13130the requirements for <tt>C1::time_point</tt> require <tt>C1</tt> and <tt>C2</tt> 13131to "refer to the same epoch", but "epoch" is not defined. 13132</li> 13133<li> 13134"Different clocks may share a <tt>time_point</tt> definition if it is 13135valid to compare their <tt>time_point</tt>s by comparing their 13136respective <tt>duration</tt>s." What does "valid" mean here? And, since 13137<tt>C1::rep</tt> is "**THE** representation type of the native 13138<tt>duration</tt> and <tt>time_point</tt>" (emphasis added), there 13139doesn't seem to be much room for some other representation. 13140</li> 13141<li> 13142<tt>C1::is_monotonic</tt> has type "<tt>const bool</tt>". The 13143"<tt>const</tt>" should be removed. 13144</li> 13145<li> 13146<tt>C1::period</tt> has type <tt>ratio</tt>. <tt>ratio</tt> isn't a type, 13147it's a template. What is the required type? 13148</li> 13149</ol> 13150 13151<p><i>[ 131522009-05-10 Howard adds: 13153]</i></p> 13154 13155 13156<ol type="a"> 13157<li> 13158<p> 13159"epoch" is purposefully not defined beyond the common English 13160<a href="http://www.dictionary.net/epoch">definition</a>. The C standard 13161also chose not to define epoch, though POSIX did. I believe it is a strength 13162of the C standard that epoch is not defined. When it is known that two <tt>time_point</tt>s 13163refer to the same epoch, then a definition of the epoch is not needed to compare 13164the two <tt>time_point</tt>s, or subtract them. 13165</p> 13166<p> 13167A <tt>time_point</tt> and a <tt>Clock</tt> implicitly refer to an (unspecified) epoch. 13168The <tt>time_point</tt> represents an offset (<tt>duration</tt>) from an epoch. 13169</p> 13170</li> 13171<li> 13172<p> 13173The sentence: 13174</p> 13175<blockquote> 13176Different clocks 13177may share a <tt>time_point</tt> 13178definition if it is valid to 13179compare their <tt>time_point</tt>s by 13180comparing their respective 13181<tt>duration</tt>s. 13182</blockquote> 13183 13184<p> 13185is redundant and could be removed. I believe the sentence which follows the above: 13186</p> 13187 13188<blockquote> 13189<tt>C1</tt> and <tt>C2</tt> shall refer to the same epoch. 13190</blockquote> 13191 13192<p> 13193is sufficient. If two clocks share the same epoch, then by definition, comparing 13194their <tt>time_point</tt>s is valid. 13195</p> 13196</li> 13197<li> 13198<tt>is_monotonic</tt> is meant to never change (be <tt>const</tt>). It is also 13199desired that this value be usable in compile-time computation and branching. 13200</li> 13201<li> 13202<p> 13203This should probably instead be worded: 13204</p> 13205<blockquote> 13206An instantiation of <tt>ratio</tt>. 13207</blockquote> 13208</li> 13209</ol> 13210 13211<p><i>[ 13212Batavia (2009-05): 13213]</i></p> 13214 13215<blockquote> 13216<p> 13217Re (a): It is not clear to us whether "epoch" is a term of art. 13218</p> 13219<p> 13220Re (b), (c), and (d): We agree with Howard's comments, 13221and would consider adding to (c) a <tt>static constexpr</tt> requirement. 13222</p> 13223<p> 13224Move to Open pending proposed wording. 13225</p> 13226</blockquote> 13227 13228<p><i>[ 132292009-05-25 Daniel adds: 13230]</i></p> 13231 13232 13233<blockquote> 13234In regards to (d) I suggest to say "a specialization of ratio" instead of 13235"An instantiation of ratio". This seems to be the better matching standard 13236core language term for this kind of entity. 13237</blockquote> 13238 13239<p><i>[ 132402009-05-25 Ganesh adds: 13241]</i></p> 13242 13243 13244<blockquote> 13245<p> 13246Regarding (a), I found this paper on the ISO website using the term "epoch" consistently with the current wording: 13247</p> 13248 13249<p> 13250<a href="http://standards.iso.org/ittf/PubliclyAvailableStandards/C030811e_FILES/MAIN_C030811e/text/ISOIEC_18026E_TEMPORAL_CS.HTM">http://standards.iso.org/ittf/PubliclyAvailableStandards/C030811e_FILES/MAIN_C030811e/text/ISOIEC_18026E_TEMPORAL_CS.HTM</a> 13251</p> 13252<p> 13253which is part of ISO/IEC 18026 "Information technology -- Spatial Reference Model (SRM)". 13254</p> 13255</blockquote> 13256 13257<p><i>[ 132582009-08-01 Howard: Moved to Reivew as the wording requested in Batavia has been provided. 13259]</i></p> 13260 13261 13262<p><i>[ 132632009-10 Santa Cruz: 13264]</i></p> 13265 13266 13267<blockquote> 13268Move to Ready. 13269</blockquote> 13270 13271 13272 13273<p><b>Proposed resolution:</b></p> 13274<ol type="a"> 13275<li> 13276<p> 13277Change 20.9.1 [time.clock.req] p1: 13278</p> 13279<blockquote> 13280-1- A clock is a bundle consisting of a native <tt>duration</tt>, a native <tt>time_point</tt>, and a function <tt>now()</tt> to get the 13281current <tt>time_point</tt>. <ins>The origin of the clock's <tt>time_point</tt> is referred to as the clock's <i>epoch</i> as defined in 13282section 6.3 of ISO/IEC 18026.</ins> 13283A clock shall meet the requirements in Table 45. 13284</blockquote> 13285</li> 13286<li> 13287<p> 13288Remove the sentence from the <tt>time_point</tt> row of the table "Clock Requirements": 13289</p> 13290<table border="1"> 13291<caption>Clock requirements</caption> 13292<tbody><tr> 13293<td> 13294<tt>C1::time_point</tt> 13295</td> 13296<td> 13297<tt>chrono::time_point<C1></tt> or <tt>chrono::time_point<C2, C1::duration></tt> 13298</td> 13299<td> 13300The native <tt>time_point</tt> type of the clock. 13301<del>Different clocks may share a <tt>time_point</tt> definition if it is valid to compare their <tt>time_point</tt>s by comparing their respective <tt>duration</tt>s.</del> 13302<tt>C1</tt> and <tt>C2</tt> shall refer to the same epoch. 13303</td> 13304</tr> 13305</tbody></table> 13306</li> 13307</ol> 13308<ol start="4" type="a"> 13309<li> 13310<p> 13311Change the row starting with <tt>C1::period</tt> of the table "Clock Requirements": 13312</p> 13313<table border="1"> 13314<caption>Clock requirements</caption> 13315<tbody><tr> 13316<td> 13317<tt>C1::period</tt> 13318</td> 13319<td> 13320<ins>a specialization of</ins> <tt>ratio</tt> 13321</td> 13322<td> 13323The tick period of the clock in seconds. 13324</td> 13325</tr> 13326</tbody></table> 13327 13328</li> 13329</ol> 13330 13331 13332 13333 13334 13335<hr> 13336<h3><a name="956"></a>956. Various threading bugs #6</h3> 13337<p><b>Section:</b> 20.9.1 [time.clock.req] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 13338 <b>Submitter:</b> Pete Becker <b>Opened:</b> 2009-01-07 <b>Last modified:</b> 2009-10-24</p> 13339<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#time.clock.req">active issues</a> in [time.clock.req].</p> 13340<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#time.clock.req">issues</a> in [time.clock.req].</p> 13341<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 13342<p><b>Discussion:</b></p> 13343<p> 1334420.9.1 [time.clock.req] uses the word "native" in several places, 13345but doesn't define it. What is a "native <tt>duration</tt>"? 13346</p> 13347 13348<p><i>[ 133492009-05-10 Howard adds: 13350]</i></p> 13351 13352 13353<blockquote> 13354The standard uses "native" in several places without defining it (e.g. 133552.14.3 [lex.ccon]). It is meant to mean "that which is defined 13356by the facility", or something along those lines. In this case it refers 13357to the nested <tt>time_point</tt> and <tt>duration</tt> types of the clock. 13358Better wording is welcome. 13359</blockquote> 13360 13361<p><i>[ 13362Batavia (2009-05): 13363]</i></p> 13364 13365<blockquote> 13366Move to Open pending proposed wording from Pete. 13367</blockquote> 13368 13369<p><i>[ 133702009-10-23 Pete provides wording: 13371]</i></p> 13372 13373 13374 13375<p><b>Proposed resolution:</b></p> 13376<p> 13377Remove every occurrence of "native" in 20.9.1 [time.clock.req]. 13378</p> 13379 13380<p> 13381Add the following sentence at the end of 20.9.1 [time.clock.req]/1: 13382</p> 13383 13384<blockquote> 13385A clock is a bundle consisting of a <del>native</del> <tt>duration</tt>, a <del>native</del> 13386<tt>time_point</tt>, and a function <tt>now()</tt> to get the current <tt>time_point</tt>. A clock 13387shall meet the requirements in Table 55. 13388<ins>The <tt>duration</tt> and <tt>time_point</tt> types have the natural size and resolution 13389suggested by the architecture of the execution environment.</ins> 13390</blockquote> 13391 13392 13393 13394 13395 13396<hr> 13397<h3><a name="957"></a>957. Various threading bugs #7</h3> 13398<p><b>Section:</b> 20.9.5.1 [time.clock.system] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 13399 <b>Submitter:</b> Pete Becker <b>Opened:</b> 2009-01-07 <b>Last modified:</b> 2009-10-21</p> 13400<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#time.clock.system">issues</a> in [time.clock.system].</p> 13401<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 13402<p><b>Discussion:</b></p> 13403<p> 1340420.9.5.1 [time.clock.system]: <tt>to_time_t</tt> is overspecified. It 13405requires truncation, but should allow rounding. For example, suppose a 13406system has a clock that gives times in milliseconds, but <tt>time()</tt> rounds 13407those times to the nearest second. Then <tt>system_clock</tt> can't use any 13408resolution finer than one second, because if it did, truncating times 13409between half a second and a full second would produce the wrong <tt>time_t</tt> 13410value. 13411</p> 13412 13413<p><i>[ 13414Post Summit Anthony Williams provided proposed wording. 13415]</i></p> 13416 13417 13418<p><i>[ 13419Batavia (2009-05): 13420]</i></p> 13421 13422<blockquote> 13423Move to Review pending input from Howard. and other stakeholders. 13424</blockquote> 13425 13426<p><i>[ 134272009-05-23 Howard adds: 13428]</i></p> 13429 13430 13431<blockquote> 13432I am in favor of the wording provided by Anthony. 13433</blockquote> 13434 13435<p><i>[ 134362009-10 Santa Cruz: 13437]</i></p> 13438 13439 13440<blockquote> 13441Move to Ready. 13442</blockquote> 13443 13444 13445 13446<p><b>Proposed resolution:</b></p> 13447<p> 13448In 20.9.5.1 [time.clock.system] replace paragraphs 3 and 4 with: 13449</p> 13450 13451<blockquote> 13452<pre>time_t to_time_t(const time_point& t); 13453</pre> 13454<blockquote> 13455-3- <i>Returns:</i> A <tt>time_t</tt> object that represents the same 13456point in time as <tt>t</tt> when both values are <del>truncated</del> 13457<ins>restricted</ins> to the coarser of the precisions of 13458<tt>time_t</tt> and <tt>time_point</tt>. <ins> It is implementation 13459defined whether values are rounded or truncated to the required 13460precision.</ins> 13461</blockquote> 13462 13463<pre>time_point from_time_t(time_t t); 13464</pre> 13465<blockquote> 13466-4- <i>Returns:</i> A <tt>time_point</tt> object that represents the 13467same point in time as <tt>t</tt> when both values are <del>truncated</del> 13468<ins>restricted</ins> to the 13469coarser of the precisions of <tt>time_t</tt> and <tt>time_point</tt>. 13470<ins>It is implementation defined whether values are 13471rounded or truncated to the required precision.</ins> 13472</blockquote> 13473</blockquote> 13474 13475 13476 13477 13478 13479<hr> 13480<h3><a name="959"></a>959. Various threading bugs #9</h3> 13481<p><b>Section:</b> 30.5.1 [thread.condition.condvar] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 13482 <b>Submitter:</b> Pete Becker <b>Opened:</b> 2009-01-07 <b>Last modified:</b> 2009-10-26</p> 13483<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#thread.condition.condvar">active issues</a> in [thread.condition.condvar].</p> 13484<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#thread.condition.condvar">issues</a> in [thread.condition.condvar].</p> 13485<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 13486<p><b>Discussion:</b></p> 13487<p> 1348830.5.1 [thread.condition.condvar]: <tt>condition_variable::wait_for</tt> 13489is required to compute the absolute time by adding the duration value to 13490<tt>chrono::monotonic_clock::now()</tt>, but <tt>monotonic_clock</tt> is not required to 13491exist. 13492</p> 13493 13494<p><i>[ 13495Summit: 13496]</i></p> 13497 13498 13499<blockquote> 13500Move to open. Associate with LWG <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#859">859</a> and any other monotonic-clock 13501related issues. 13502</blockquote> 13503 13504<p><i>[ 135052009-08-01 Howard adds: 13506]</i></p> 13507 13508 13509<blockquote> 13510I believe that <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#859">859</a> (currently Ready) addresses this issue, and 13511that this issue should be marked NAD, solved by <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#859">859</a> (assuming 13512it moves to WP). 13513</blockquote> 13514 13515<p><i>[ 135162009-10 Santa Cruz: 13517]</i></p> 13518 13519 13520<blockquote> 13521Leave open, but expect to be fixed by N2969 revision that Detlef is writing. 13522</blockquote> 13523 13524 13525 13526<p><b>Proposed resolution:</b></p> 13527<p> 13528</p> 13529 13530 13531 13532 13533 13534<hr> 13535<h3><a name="960"></a>960. Various threading bugs #10</h3> 13536<p><b>Section:</b> 30.4.1 [thread.mutex.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 13537 <b>Submitter:</b> Pete Becker <b>Opened:</b> 2009-01-07 <b>Last modified:</b> 2009-10-26</p> 13538<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#thread.mutex.requirements">active issues</a> in [thread.mutex.requirements].</p> 13539<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#thread.mutex.requirements">issues</a> in [thread.mutex.requirements].</p> 13540<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 13541<p><b>Discussion:</b></p> 13542<p> 1354330.4.1 [thread.mutex.requirements]: paragraph 4 is entitled 13544"Error conditions", but according to 17.5.1.4 [structure.specifications], "Error 13545conditions:" specifies "the error conditions for error codes reported by 13546the function." It's not clear what this should mean when there is no 13547function in sight. 13548</p> 13549 13550<p><i>[ 13551Summit: 13552]</i></p> 13553 13554 13555<blockquote> 13556Move to open. 13557</blockquote> 13558 13559<p><i>[ 13560Beman provided proposed wording. 13561]</i></p> 13562 13563 13564<p><i>[ 135652009-10 Santa Cruz: 13566]</i></p> 13567 13568 13569<blockquote> 13570Move to Ready. Fix the proposed wording with "functions of type Mutex" 13571-> "functions of Mutex type" 13572</blockquote> 13573 13574 13575 13576<p><b>Proposed resolution:</b></p> 13577<p> 13578Change 30.4.1 [thread.mutex.requirements] Mutex requirements, 13579paragraph 4 as indicated: 13580</p> 13581 13582<blockquote> 13583<p> 13584-4- <del><i>Error conditions:</i></del> 13585<ins>The error conditions for error codes, if any, reported by member 13586functions of Mutex type shall be:</ins> 13587</p> 13588<ul> 13589<li> 13590<tt>not_enough_memory</tt> -- if there is not enough memory to construct 13591the mutex object. 13592</li> 13593<li> 13594<tt>resource_unavailable_try_again</tt> -- if any native handle type 13595manipulated is not available. 13596</li> 13597<li> 13598<tt>operation_not_permitted</tt> -- if the thread does not have the 13599necessary permission to change the state of the mutex object. 13600</li> 13601<li> 13602<tt>device_or_resource_busy</tt> -- if any native handle type 13603manipulated is already locked. 13604</li> 13605<li> 13606<tt>invalid_argument</tt> -- if any native handle type manipulated as 13607part of mutex construction is incorrect. 13608</li> 13609</ul> 13610</blockquote> 13611 13612 13613 13614 13615 13616<hr> 13617<h3><a name="962"></a>962. Various threading bugs #12</h3> 13618<p><b>Section:</b> 30.4.3.2.2 [thread.lock.unique.locking] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 13619 <b>Submitter:</b> Pete Becker <b>Opened:</b> 2009-01-07 <b>Last modified:</b> 2009-10-22</p> 13620<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#thread.lock.unique.locking">active issues</a> in [thread.lock.unique.locking].</p> 13621<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#thread.lock.unique.locking">issues</a> in [thread.lock.unique.locking].</p> 13622<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 13623<p><b>Discussion:</b></p> 13624<p> 1362530.4.3.2.2 [thread.lock.unique.locking]: <tt>unique_lock::lock</tt> is 13626required to throw an object of type <tt>std::system_error</tt> "when the 13627postcondition cannot be achieved." The postcondition is <tt>owns == true</tt>, 13628and this is trivial to achieve. Presumably, the requirement is intended 13629to mean something more than that. 13630</p> 13631 13632<p><i>[ 13633Summit: 13634]</i></p> 13635 13636<blockquote> 13637Move to open. 13638</blockquote> 13639 13640<p><i>[ 13641Beman has volunteered to provide proposed wording. 13642]</i></p> 13643 13644 13645<p><i>[ 136462009-07-21 Beman added wording to address 30.2.2 [thread.req.exception] 13647in response to the Frankfurt notes in <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#859">859</a>. 13648]</i></p> 13649 13650 13651<p><i>[ 136522009-09-25 Beman: minor update to wording. 13653]</i></p> 13654 13655 13656<p><i>[ 136572009-10 Santa Cruz: 13658]</i></p> 13659 13660 13661<blockquote> 13662Move to Ready. 13663</blockquote> 13664 13665 13666 13667<p><b>Proposed resolution:</b></p> 13668 13669<p><i>Change Exceptions 30.2.2 [thread.req.exception] as indicated:</i></p> 13670<blockquote> 13671<p>Some functions described in this Clause are specified to throw exceptions of 13672type <code>system_error</code> (19.5.5). Such exceptions shall be thrown if <ins> 13673any of the <i>Error conditions</i> are detected or</ins> a call to an operating 13674system or other underlying API results in an error that prevents the library 13675function from <del>satisfying its postconditions or from returning a meaningful 13676value</del> <ins>meeting its specifications</ins>. <ins>Failure to 13677allocate storage shall be reported as described in 1367817.6.4.11 [res.on.exception.handling].</ins></p> 13679</blockquote> 13680 13681<p><i>Change thread assignment 30.3.1.5 [thread.thread.member], join(), 13682paragraph 8 as indicated:</i></p> 13683<blockquote> 13684<p><i>Throws:</i> <code>std::system_error</code> when <del>the postconditions cannot be achieved</del> <ins>an exception is required (30.2.2 [thread.req.exception])</ins>.</p> 13685 13686</blockquote> 13687 13688<p><i>Change thread assignment 30.3.1.5 [thread.thread.member], detach(), paragraph 1368913 as indicated:</i></p> 13690<blockquote> 13691 13692<p><i>Throws:</i> <code>std::system_error</code> when <del>the effects or 13693postconditions cannot be achieved</del> <ins>an exception is required (30.2.2 [thread.req.exception])</ins>.</p> 13694 13695</blockquote> 13696 13697<p><i>Change Mutex requirements 30.4.1 [thread.mutex.requirements], paragraph 1369811, as indicated:</i></p> 13699<blockquote> 13700 13701<p><i>Throws:</i> <code>std::system_error</code> when <del>the effects or 13702postcondition cannot be achieved</del> <ins>an exception is required (30.2.2 [thread.req.exception])</ins>.</p> 13703</blockquote> 13704<p><i>Change unique_lock locking 30.4.3.2.2 [thread.lock.unique.locking], 13705paragraph 3, as indicated:</i></p> 13706<blockquote> 13707 13708<p><i>Throws:</i> <code>std::system_error</code> when <del>the postcondition cannot be achieved</del> <ins>an exception is required (30.2.2 [thread.req.exception])</ins>.</p> 13709</blockquote> 13710<p><i>Change unique_lock locking 30.4.3.2.2 [thread.lock.unique.locking], 13711paragraph 8, as indicated:</i></p> 13712<blockquote> 13713 13714<p><i>Throws:</i> <code>std::system_error</code> when <del>the postcondition cannot be achieved</del> <ins>an exception is required (30.2.2 [thread.req.exception])</ins>.</p> 13715</blockquote> 13716<p><i>Change unique_lock locking 30.4.3.2.2 [thread.lock.unique.locking], 13717paragraph 13, as indicated:</i></p> 13718<blockquote> 13719 13720<p><i>Throws:</i> <code>std::system_error</code> when <del>the postcondition cannot be achieved</del> <ins>an exception is required (30.2.2 [thread.req.exception])</ins>.</p> 13721</blockquote> 13722<p><i>Change unique_lock locking 30.4.3.2.2 [thread.lock.unique.locking], 13723paragraph 18, as indicated:</i></p> 13724<blockquote> 13725 13726<p><i>Throws:</i> <code>std::system_error</code> when <del>the postcondition cannot be achieved</del> <ins>an exception is required (30.2.2 [thread.req.exception])</ins>.</p> 13727</blockquote> 13728<p><i>Change unique_lock locking 30.4.3.2.2 [thread.lock.unique.locking], 13729paragraph 22, as indicated:</i></p> 13730<blockquote> 13731 13732<p><i>Throws:</i> <code>std::system_error</code> when <del>the postcondition cannot be achieved</del> <ins>an exception is required (30.2.2 [thread.req.exception])</ins>.</p> 13733</blockquote> 13734<p><i>Change Function call_once 30.4.5.2 [thread.once.callonce], paragraph 4, as 13735indicated</i></p> 13736<blockquote> 13737 <p><i>Throws:</i> <code>std::system_error</code> when <del>the effects cannot be achieved</del> <ins>an exception is required (30.2.2 [thread.req.exception])</ins>, 13738 or any exception thrown by <code>func</code>.</p> 13739</blockquote> 13740<p><i>Change Class condition_variable 30.5.1 [thread.condition.condvar], 13741paragraph 12, as indicated:</i></p> 13742<blockquote> 13743 13744<p><i>Throws:</i> <code>std::system_error</code> when <del>the effects or 13745postcondition cannot be achieved</del> <ins>an exception is required (30.2.2 [thread.req.exception])</ins>.</p> 13746</blockquote> 13747<p><i>Change Class condition_variable 30.5.1 [thread.condition.condvar], 13748paragraph 19, as indicated:</i></p> 13749<blockquote> 13750 13751<p><i>Throws:</i> <code>std::system_error</code> when <del>the effects or 13752postcondition cannot be achieved</del> <ins>an exception is required (30.2.2 [thread.req.exception])</ins>.</p> 13753</blockquote> 13754<p><i>Change Class condition_variable_any 30.5.2 [thread.condition.condvarany], 13755paragraph 10, as indicated:</i></p> 13756<blockquote> 13757 13758<p><i>Throws:</i> <code>std::system_error</code> when <del>the effects or 13759postcondition cannot be achieved</del> <ins>an exception is required (30.2.2 [thread.req.exception])</ins>.</p> 13760</blockquote> 13761<p><i>Change Class condition_variable_any 30.5.2 [thread.condition.condvarany], 13762paragraph 16, as indicated:</i></p> 13763<blockquote> 13764 13765<p><i>Throws:</i> <code>std::system_error</code> when <del>the returned value, effects, or 13766postcondition cannot be achieved</del> <ins>an exception is required (30.2.2 [thread.req.exception])</ins>.</p> 13767</blockquote> 13768 13769<p><i>Assuming issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#859">859</a>, Monotonic Clock is Conditionally Supported?, has been 13770applied to the working paper, change Change 30.5.1 [thread.condition.condvar] as 13771indicated:</i></p> 13772<blockquote> 13773<pre>template <class Rep, class Period> 13774bool wait_for(unique_lock<mutex>& lock, 13775 const chrono::duration<Rep, Period>& rel_time);</pre> 13776<pre>...</pre> 13777 13778<p><i>Throws:</i> <code>std::system_error</code> when <del>the effects or 13779postcondition cannot be achieved</del> <ins>an exception is required ([thread.req.exception])</ins>.</p> 13780</blockquote> 13781 13782<p><i>Assuming issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#859">859</a>, Monotonic Clock is Conditionally Supported?, has been 13783applied to the working paper, change Change 30.5.1 [thread.condition.condvar] as 13784indicated:</i></p> 13785<blockquote> 13786<pre>template <class Rep, class Period, class Predicate> 13787 bool wait_for(unique_lock<mutex>& lock, 13788 const chrono::duration<Rep, Period>& rel_time, 13789 Predicate pred);</pre> 13790 <pre>...</pre> 13791 13792<p><i>Throws:</i> <code>std::system_error</code> when <del>the effects or 13793postcondition cannot be achieved</del> <ins>an exception is required (30.2.2 [thread.req.exception])</ins>.</p> 13794</blockquote> 13795 13796<p><i>Assuming issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#859">859</a>, Monotonic Clock is Conditionally Supported?, has been 13797applied to the working paper, change 30.5.2 [thread.condition.condvarany] as 13798indicated:</i></p> 13799<blockquote> 13800<pre>template <class Lock, class Rep, class Period> 13801 bool wait_for(Lock& lock, const chrono::duration<Rep, Period>& rel_time);</pre> 13802 <pre>...</pre> 13803 13804<p><i>Throws:</i> <code>std::system_error</code> when <del>the returned value, effects or 13805postcondition cannot be achieved</del> <ins>an exception is required (30.2.2 [thread.req.exception])</ins>.</p> 13806</blockquote> 13807 13808<p><i>Assuming issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#859">859</a>, Monotonic Clock is Conditionally Supported?, has been 13809applied to the working paper, change 30.5.2 [thread.condition.condvarany] as 13810indicated:</i></p> 13811<blockquote> 13812<pre>template <class Lock, class Rep, class Period, class Predicate> 13813 bool wait_for(Lock& lock, const chrono::duration<Rep, Period>& rel_time, Predicate pred);</pre> 13814 <pre>...</pre> 13815 13816<p><i>Throws:</i> <code>std::system_error</code> when <del>the returned value, effects or 13817postcondition cannot be achieved</del> <ins>an exception is required (30.2.2 [thread.req.exception])</ins>.</p> 13818</blockquote> 13819 13820 13821 13822 13823 13824 13825<hr> 13826<h3><a name="963"></a>963. Various threading bugs #13</h3> 13827<p><b>Section:</b> 30.3.1.5 [thread.thread.member] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 13828 <b>Submitter:</b> Pete Becker <b>Opened:</b> 2009-01-07 <b>Last modified:</b> 2009-10-26</p> 13829<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#thread.thread.member">active issues</a> in [thread.thread.member].</p> 13830<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#thread.thread.member">issues</a> in [thread.thread.member].</p> 13831<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 13832<p><b>Discussion:</b></p> 13833<p> 1383430.3.1.5 [thread.thread.member]: <tt>thread::detach</tt> is required to 13835throw an exception if the thread is "not a detachable thread". 13836"Detachable" is never defined. 13837</p> 13838 13839<p><i>[ 13840Howard adds: 13841]</i></p> 13842 13843 13844<blockquote> 13845Due to a mistake on my part, 3 proposed resolutions appeared at approximately 13846the same time. They are all three noted below in the discussion. 13847</blockquote> 13848 13849<p><i>[ 13850Summit, proposed resolution: 13851]</i></p> 13852 13853 13854<blockquote> 13855<p> 13856In 30.3.1.5 [thread.thread.member] change: 13857</p> 13858 13859<blockquote><pre>void detach(); 13860</pre> 13861<blockquote> 13862<p>...</p> 13863<p>-14- <i>Error conditions:</i></p> 13864<ul> 13865<li><tt>no_such_process</tt> -- <ins>if the thread is</ins> not <del>a</del> valid<del> thread</del>.</li> 13866<li><tt>invalid_argument</tt> -- <ins>if the thread is</ins> not <del>a detachable</del> <ins>joinable</ins><del> thread</del>.</li> 13867</ul> 13868</blockquote> 13869 13870</blockquote> 13871 13872</blockquote> 13873 13874<p><i>[ 13875Post Summit, Jonathan Wakely adds: 13876]</i></p> 13877 13878 13879<blockquote> 13880<p> 13881A <tt>thread</tt> is detachable if it is joinable. As we've defined joinable, 13882we can just use that. 13883</p> 13884<p> 13885This corresponds to the pthreads specification, where pthread_detach 13886fails if the thread is not joinable: 13887</p> 13888<blockquote> 13889EINVAL: The implementation has detected that the value specified by 13890thread does not refer to a joinable thread. 13891</blockquote> 13892<p> 13893Jonathan recommends this proposed wording: 13894</p> 13895<blockquote> 13896<p> 13897In 30.3.1.5 [thread.thread.member] change: 13898</p> 13899 13900<blockquote><pre>void detach(); 13901</pre> 13902<blockquote> 13903<p>...</p> 13904<p>-14- <i>Error conditions:</i></p> 13905<ul> 13906<li>...</li> 13907<li><tt>invalid_argument</tt> -- not a <del>detachable</del> <ins>joinable</ins> thread.</li> 13908</ul> 13909</blockquote> 13910 13911</blockquote> 13912</blockquote> 13913</blockquote> 13914 13915<p><i>[ 13916Post Summit, Anthony Williams adds: 13917]</i></p> 13918 13919 13920<blockquote> 13921<p> 13922This is covered by the precondition that <tt>joinable()</tt> be <tt>true</tt>. 13923</p> 13924<p> 13925Anthony recommends this proposed wording: 13926</p> 13927 13928<blockquote> 13929<p> 13930In 30.3.1.5 [thread.thread.member] change: 13931</p> 13932 13933<blockquote><pre>void detach(); 13934</pre> 13935<blockquote> 13936<p>...</p> 13937<p>-14- <i>Error conditions:</i></p> 13938<ul> 13939<li>...</li> 13940<li><del><tt>invalid_argument</tt> -- not a detachable thread.</del></li> 13941</ul> 13942</blockquote> 13943 13944</blockquote> 13945 13946</blockquote> 13947 13948</blockquote> 13949 13950<p><i>[ 139512009-10 Santa Cruz: 13952]</i></p> 13953 13954 13955<blockquote> 13956Mark as Ready with proposed resolution from Summit. 13957</blockquote> 13958 13959 13960 13961<p><b>Proposed resolution:</b></p> 13962 13963<p> 13964In 30.3.1.5 [thread.thread.member] change: 13965</p> 13966 13967<blockquote><pre>void detach(); 13968</pre> 13969<blockquote> 13970<p>...</p> 13971<p>-14- <i>Error conditions:</i></p> 13972<ul> 13973<li><tt>no_such_process</tt> -- <ins>if the thread is</ins> not <del>a</del> valid<del> thread</del>.</li> 13974<li><tt>invalid_argument</tt> -- <ins>if the thread is</ins> not <del>a detachable</del> <ins>joinable</ins><del> thread</del>.</li> 13975</ul> 13976</blockquote> 13977 13978</blockquote> 13979 13980 13981 13982 13983 13984 13985<hr> 13986<h3><a name="964"></a>964. Various threading bugs #14</h3> 13987<p><b>Section:</b> 30.5.2 [thread.condition.condvarany] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 13988 <b>Submitter:</b> Pete Becker <b>Opened:</b> 2009-01-07 <b>Last modified:</b> 2009-10-26</p> 13989<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#thread.condition.condvarany">active issues</a> in [thread.condition.condvarany].</p> 13990<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#thread.condition.condvarany">issues</a> in [thread.condition.condvarany].</p> 13991<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 13992<p><b>Discussion:</b></p> 13993<p> 13994The requirements for the constructor for <tt>condition_variable</tt> has several 13995error conditions, but the requirements for the constructor for 13996<tt>condition_variable_any</tt> has none. Is this difference intentional? 13997</p> 13998 13999<p><i>[ 14000Summit: 14001]</i></p> 14002 14003 14004<blockquote> 14005Move to open, pass to Howard. If this is intentional, a note may be 14006helpful. If the error conditions are to be copied from 14007<tt>condition_variable</tt>, this depends on LWG <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#965">965</a>. 14008</blockquote> 14009 14010<p><i>[ 14011Post Summit Howard adds: 14012]</i></p> 14013 14014 14015<blockquote> 14016The original intention 14017(<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2447.htm#ConditionVariablesWording">N2447</a>) 14018was to let the OS return whatever errors it was going to return, and for 14019those to be translated into exceptions, for both 14020<tt>condition_variable</tt> and <tt>condition_variable_any</tt>. I have not 14021received any complaints about specific error conditions from vendors on 14022non-POSIX platforms, but such complaints would not surprise me if they surfaced. 14023</blockquote> 14024 14025<p><i>[ 140262009-10 Santa Cruz: 14027]</i></p> 14028 14029 14030<blockquote> 14031Leave open. Benjamin to provide wording. 14032</blockquote> 14033 14034 14035 14036<p><b>Proposed resolution:</b></p> 14037 14038 14039 14040 14041 14042<hr> 14043<h3><a name="966"></a>966. Various threading bugs #16</h3> 14044<p><b>Section:</b> 30.5.1 [thread.condition.condvar] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 14045 <b>Submitter:</b> Pete Becker <b>Opened:</b> 2009-01-07 <b>Last modified:</b> 2009-10-26</p> 14046<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#thread.condition.condvar">active issues</a> in [thread.condition.condvar].</p> 14047<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#thread.condition.condvar">issues</a> in [thread.condition.condvar].</p> 14048<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 14049<p><b>Discussion:</b></p> 14050<p> 1405130.5.1 [thread.condition.condvar]: 14052<tt>condition_variable::wait</tt> and 14053<tt>condition_variable::wait_until</tt> both have a postcondition that 14054<tt>lock</tt> is locked by the calling thread, and a throws clause that 14055requires throwing an exception if this postcondition cannot be achieved. 14056How can the implementation detect that this <tt>lock</tt> can never be 14057obtained? 14058</p> 14059 14060<p><i>[ 14061Summit: 14062]</i></p> 14063 14064 14065<blockquote> 14066Move to open. Requires wording. Agreed this is an issue, and the 14067specification should not require detecting deadlocks. 14068</blockquote> 14069 14070<p><i>[ 140712009-08-01 Howard provides wording. 14072]</i></p> 14073 14074 14075<blockquote> 14076<p> 14077The proposed wording is inspired by the POSIX spec which says: 14078</p> 14079 14080<blockquote> 14081<dl> 14082<dt>[EINVAL]</dt> 14083<dd>The value specified by cond or mutex is invalid.</dd> 14084<dt>[EPERM]</dt> 14085<dd>The mutex was not owned by the current thread at the time of the call.</dd> 14086</dl> 14087</blockquote> 14088 14089<p> 14090I do not believe [EINVAL] is possible without memory corruption (which we don't 14091specify). [EPERM] is possible if this thread doesn't own the mutex, which is 14092listed as a precondition. "May" is used instead of "Shall" because not all 14093OS's are POSIX. 14094</p> 14095</blockquote> 14096 14097<p><i>[ 140982009-10 Santa Cruz: 14099]</i></p> 14100 14101 14102<blockquote> 14103Leave open, Detlef to provide improved wording. 14104</blockquote> 14105 14106<p><i>[ 141072009-10-23 Detlef Provided wording. 14108]</i></p> 14109 14110 14111<blockquote> 14112<p> 14113Detlef's wording put in Proposed resolution. Original wording here: 14114</p> 14115<blockquote> 14116<p> 14117Change 30.5.1 [thread.condition.condvar] p12, p19 and 1411830.5.2 [thread.condition.condvarany] p10, p16: 14119</p> 14120 14121<blockquote> 14122<i>Throws:</i> <ins>May throw</ins> <tt>std::system_error</tt> 14123<ins> 14124if a precondition is not met. 14125</ins> 14126<del>when the effects or postcondition 14127cannot be achieved.</del> 14128</blockquote> 14129</blockquote> 14130</blockquote> 14131 14132<p><i>[ 141332009-10 Santa Cruz: 14134]</i></p> 14135 14136 14137<blockquote> 14138Leave open, Detlef to provide improved wording. 14139</blockquote> 14140 14141 14142 14143<p><b>Proposed resolution:</b></p> 14144<p> 14145Replace 30.5.1 [thread.condition.condvar] p12, p19 and 1414630.5.2 [thread.condition.condvarany] p10, p16: 14147</p> 14148 14149<blockquote> 14150<p><del> 14151<i>Throws:</i> <tt>std::system_error</tt> when the effects or 14152postcondition cannot be achieved. 14153</del></p> 14154<p><del> 14155Error conditions: 14156</del></p> 14157<ul> 14158<li><del> 14159equivalent error condition from <tt>lock.lock()</tt> or <tt>lock.unlock()</tt>. 14160</del></li> 14161</ul> 14162 14163<p><ins> 14164<i>Throws:</i> It's implementation-defined whether a <tt>std::system_error</tt> 14165with implementation-defined error condition is thrown if the 14166precondition is not met. 14167</ins></p> 14168</blockquote> 14169 14170 14171 14172 14173 14174 14175<hr> 14176<h3><a name="967"></a>967. Various threading bugs #17</h3> 14177<p><b>Section:</b> 30.3.1.2 [thread.thread.constr] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 14178 <b>Submitter:</b> Pete Becker <b>Opened:</b> 2009-01-07 <b>Last modified:</b> 2009-10-22</p> 14179<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#thread.thread.constr">active issues</a> in [thread.thread.constr].</p> 14180<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#thread.thread.constr">issues</a> in [thread.thread.constr].</p> 14181<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 14182<p><b>Discussion:</b></p> 14183<p> 14184the error handling for the constructor for <tt>condition_variable</tt> 14185distinguishes lack of memory from lack of other resources, but the error 14186handling for the thread constructor does not. Is this difference 14187intentional? 14188</p> 14189 14190<p><i>[ 14191Beman has volunteered to provide proposed wording. 14192]</i></p> 14193 14194 14195<p><i>[ 141962009-09-25 Beman provided proposed wording. 14197]</i></p> 14198 14199 14200<blockquote> 14201The proposed resolution assumes <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#962">962</a> has been accepted and 14202its proposed resolution applied to the working paper. 14203</blockquote> 14204 14205<p><i>[ 142062009-10 Santa Cruz: 14207]</i></p> 14208 14209 14210<blockquote> 14211Move to Ready. 14212</blockquote> 14213 14214 14215 14216<p><b>Proposed resolution:</b></p> 14217 14218 14219<p><span style="font-style: italic;">Change Mutex requirements 30.4.1 [thread.mutex.requirements], 14220paragraph 4, as indicated:</span></p> 14221<blockquote> 14222 14223<p><i>Error conditions:</i></p> 14224 <blockquote> 14225 14226<ul> 14227<li><del> <code>not_enough_memory</code> — if there is not enough memory to construct 14228the mutex object.</del></li> 14229 14230<li><code>resource_unavailable_try_again</code> — if any native handle type 14231manipulated is not available.</li> 14232 14233<li><code>operation_not_permitted</code> — if the thread does not have the 14234necessary permission to change the state of the mutex object.</li> 14235 14236<li><code>device_or_resource_busy</code> — if any native handle type 14237manipulated is already locked.</li> 14238 14239<li><code>invalid_argument</code> — if any native handle type manipulated as 14240part of mutex construction is incorrect.</li> 14241</ul> 14242 </blockquote> 14243</blockquote> 14244 14245<p><span style="font-style: italic;">Change Class condition_variable 30.5.1 [thread.condition.condvar], 14246default constructor, as indicated:</span></p> 14247<blockquote> 14248 <p><code>condition_variable();</code></p> 14249 <blockquote> 14250 <p><i>Effects:</i> Constructs an object of type <code>condition_variable</code>.</p> 14251 <p><ins><i>Throws:</i> <code>std::system_error</code> when an exception is required (30.2.2 [thread.req.exception])</ins>.</p> 14252 <p><i>Error conditions:</i></p> 14253 <blockquote> 14254 <ul> 14255 <li><del><code>not_enough_memory</code> — if a memory limitation prevents 14256 initialization.</del></li> 14257 <li> <code>resource_unavailable_try_again</code> — if some non-memory 14258 resource limitation prevents initialization.</li> 14259 <li> <code>device_or_resource_busy</code> — if attempting to initialize a 14260 previously-initialized but as of yet undestroyed <code>condition_variable</code>.</li> 14261 </ul> 14262 </blockquote> 14263 </blockquote> 14264</blockquote> 14265 14266 14267 14268 14269 14270<hr> 14271<h3><a name="968"></a>968. Various threading bugs #18</h3> 14272<p><b>Section:</b> 30.4.1 [thread.mutex.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 14273 <b>Submitter:</b> Pete Becker <b>Opened:</b> 2009-01-07 <b>Last modified:</b> 2009-10-22</p> 14274<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#thread.mutex.requirements">active issues</a> in [thread.mutex.requirements].</p> 14275<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#thread.mutex.requirements">issues</a> in [thread.mutex.requirements].</p> 14276<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 14277<p><b>Discussion:</b></p> 14278<p> 1427930.4.1 [thread.mutex.requirements]: several functions are 14280required to throw exceptions "if the thread does not have the necessary 14281permission ...". "The necessary permission" is not defined. 14282</p> 14283 14284<p><i>[ 14285Summit: 14286]</i></p> 14287 14288<blockquote> 14289Move to open. 14290</blockquote> 14291 14292 14293<p><i>[ 14294Beman has volunteered to provide proposed wording. 14295]</i></p> 14296 14297 14298<p><i>[ 142992009-10 Santa Cruz: 14300]</i></p> 14301 14302 14303<blockquote> 14304Moved to Ready with minor word-smithing in the example. 14305</blockquote> 14306 14307 14308 14309<p><b>Proposed resolution:</b></p> 14310 14311 14312<p><i>Change Exceptions 30.2.2 [thread.req.exception] as indicated:</i></p> 14313<blockquote> 14314<p>Some functions described in this Clause are 14315specified to throw exceptions of type <code>system_error</code> (19.5.5). Such exceptions 14316shall be thrown if any of the <i>Error conditions</i> are detected or a call to an operating system or other underlying API 14317results in an error that prevents the library function from meeting its specifications. 14318<i>[Note:</i> See 17.6.4.11 [res.on.exception.handling] for exceptions thrown to report 14319storage allocation failures. <i>—end 14320note]</i></p> 14321 14322<p><ins><i>[Example:</i></ins></p> 14323 14324<blockquote> 14325 14326<p><ins>Consider a function in this clause that is specified to throw exceptions of type <code> 14327system_error</code> and specifies <i>Error conditions</i> that include <code> 14328operation_not_permitted</code> for a thread that does not have the privilege to 14329perform the operation. Assume that, during the execution of this function, an <code>errno</code> 14330of <code>EPERM</code> is reported by a POSIX API call used by the 14331implementation. Since POSIX specifies an <code>errno</code> of <code>EPERM</code> 14332when "the caller does not have the privilege to perform the operation", 14333the implementation maps <code>EPERM</code> to an <code>error_condition</code> 14334of <code>operation_not_permitted</code> (19.5 [syserr]) and an exception of type <code> 14335system_error</code> is thrown. </ins></p> 14336 14337</blockquote> 14338 14339<p><ins><i>—end example]</i></ins></p> 14340 14341<p><span style="font-style: italic;">Editorial note: For the sake of exposition, 14342the existing text above is shown with the changes proposed in issues 962 and 967. The 14343proposed additional example is independent of whether or not the 962 and 967 14344proposed resolutions are accepted.</span></p> 14345 14346</blockquote> 14347 14348<p><span style="font-style: italic;">Change Mutex requirements 30.4.1 [thread.mutex.requirements], 14349paragraph 4, as indicated:</span></p> 14350 14351<blockquote> 14352 14353<p>— <code>operation_not_permitted</code> — if the thread does not have the 14354<del>necessary permission to change the state of the mutex object</del> <ins>privilege to perform the operation</ins>.</p> 14355 14356</blockquote> 14357 14358<p><span style="font-style: italic;">Change Mutex requirements 30.4.1 [thread.mutex.requirements], 14359paragraph 12, as indicated:</span></p> 14360 14361<blockquote> 14362 14363<p>— <code>operation_not_permitted</code> — if the thread does not have the 14364<del>necessary permission to change the state of the mutex</del> <ins>privilege to perform the operation</ins>.</p> 14365 14366</blockquote> 14367 14368 14369 14370 14371 14372 14373<hr> 14374<h3><a name="974"></a>974. <tt>duration<double></tt> should not implicitly convert to <tt>duration<int></tt></h3> 14375<p><b>Section:</b> 20.9.3.1 [time.duration.cons] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 14376 <b>Submitter:</b> Howard Hinnant <b>Opened:</b> 2009-01-21 <b>Last modified:</b> 2009-10-26</p> 14377<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 14378<p><b>Discussion:</b></p> 14379<p> 14380The following code should not compile because it involves implicit truncation 14381errors (against the design philosophy of the <tt>duration</tt> library). 14382</p> 14383 14384<blockquote><pre>duration<double> d(3.5); 14385duration<int> i = d; <font color="#c80000">// implicit truncation, should not compile</font> 14386</pre></blockquote> 14387 14388<p> 14389This intent was codified in the example implementation which drove this proposal 14390but I failed to accurately translate the code into the specification in this 14391regard. 14392</p> 14393 14394<p><i>[ 14395Batavia (2009-05): 14396]</i></p> 14397 14398<blockquote> 14399<p> 14400We agree with the proposed resolution. 14401</p> 14402<p> 14403Move to Tentatively Ready. 14404</p> 14405</blockquote> 14406 14407<p><i>[ 144082009-07 Frankfurt 14409]</i></p> 14410 14411 14412<blockquote> 14413Moved from Tentatively Ready to Open only because the wording needs to be 14414improved for enable_if type constraining, possibly following Robert's 14415formula. 14416</blockquote> 14417 14418<p><i>[ 144192009-08-01 Howard adds: 14420]</i></p> 14421 14422 14423<blockquote> 14424Addressed by <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1177">1177</a>. 14425</blockquote> 14426 14427<p><i>[ 144282009-10 Santa Cruz: 14429]</i></p> 14430 14431 14432<blockquote> 14433Not completely addressed by <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1177">1177</a>. Move to Ready. 14434</blockquote> 14435 14436 14437 14438<p><b>Proposed resolution:</b></p> 14439<p> 14440Change 20.9.3.1 [time.duration.cons], p4: 14441</p> 14442 14443<blockquote> 14444<pre>template <class Rep2, class Period2> 14445 duration(const duration<Rep2, Period2>& d); 14446</pre> 14447<blockquote> 14448-4- <i>Requires:</i> <tt>treat_as_floating_point<rep>::value</tt> 14449shall be <tt>true</tt> or <ins>both</ins> <tt>ratio_divide<Period2, 14450period>::type::den</tt> shall be 1 14451<ins>and <tt>treat_as_floating_point<Rep2>::value</tt> 14452shall be <tt>false</tt></ins>. 14453Diagnostic required. 14454[<i>Note:</i> This requirement prevents implicit truncation error when 14455converting between integral-based <tt>duration</tt> types. Such a 14456construction could easily lead to confusion about the value of the 14457<tt>duration</tt>. -- <i>end note</i>] 14458</blockquote> 14459</blockquote> 14460 14461 14462 14463 14464 14465<hr> 14466<h3><a name="978"></a>978. Hashing smart pointers</h3> 14467<p><b>Section:</b> 20.7.16 [unord.hash] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 14468 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-02-02 <b>Last modified:</b> 2009-10-27</p> 14469<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#unord.hash">active issues</a> in [unord.hash].</p> 14470<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#unord.hash">issues</a> in [unord.hash].</p> 14471<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 14472<p><b>Discussion:</b></p> 14473<p><b>Addresses UK 208</b></p> 14474<p> 14475I don't see an open issue on supporting <tt>std::hash</tt> for smart pointers 14476(<tt>unique_ptr</tt> and <tt>shared_ptr</tt> at least). 14477</p> 14478<p> 14479It seems reasonable to at least expect support for the smart 14480pointers, especially as they support comparison for use in ordered 14481associative containers. 14482</p> 14483 14484<p><i>[ 14485Batavia (2009-05): 14486]</i></p> 14487 14488<blockquote> 14489<p> 14490Howard points out that the client can always supply a custom hash function. 14491</p> 14492<p> 14493Alisdair replies that the smart pointer classes are highly likely 14494to be frequently used as hash keys. 14495</p> 14496<p> 14497Bill would prefer to be conservative. 14498</p> 14499<p> 14500Alisdair mentions that this issue may also be viewed as a subissue or 14501duplicate of issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1025">1025</a>. 14502</p> 14503<p> 14504Move to Open, and recommend the issue be deferred until after the next 14505Committee Draft is issued. 14506</p> 14507</blockquote> 14508 14509<p><i>[ 145102009-05-31 Peter adds: 14511]</i></p> 14512 14513 14514<blockquote> 14515<blockquote> 14516Howard points out that the client can always supply a custom hash function. 14517</blockquote> 14518<p> 14519Not entirely true. The client cannot supply the function that hashes the 14520address of the control block (the equivalent of the old <tt>operator<</tt>, now 14521proudly carrying the awkward name of '<tt>owner_before</tt>'). Only the 14522implementation can do that, not necessarily via specializing <tt>hash<></tt>, of 14523course. 14524</p> 14525<p> 14526This hash function makes sense in certain situations for <tt>shared_ptr</tt> 14527(when one needs to switch from <tt>set/map</tt> using ownership ordering to 14528<tt>unordered_set/map</tt>) and is the only hash function that makes sense for 14529<tt>weak_ptr</tt>. 14530</p> 14531</blockquote> 14532 14533<p><i>[ 145342009-07-28 Alisdair provides wording. 14535]</i></p> 14536 14537 14538<p><i>[ 145392009-10 Santa Cruz: 14540]</i></p> 14541 14542 14543<blockquote> 14544Move to Ready. 14545</blockquote> 14546 14547 14548 14549<p><b>Proposed resolution:</b></p> 14550<p> 14551Add the following declarations to the synopsis of <tt><memory></tt> 14552in 20.8 [memory] 14553</p> 14554 14555<blockquote><pre>// 20.8.10.X hash support 14556template <class T> struct hash; 14557template <class T, class D> struct hash<unique_ptr<T,D>>; 14558template <class T> struct hash<shared_ptr<T>>; 14559</pre></blockquote> 14560 14561<p> 14562Add a new subclause 20.8.10.X hash support 14563</p> 14564 14565<blockquote> 14566<p> 1456720.8.10.X hash support [util.smartptr.hash] 14568</p> 14569 14570<pre>template <class T, class D> struct hash<unique_ptr<T,D>>; 14571</pre> 14572 14573<blockquote> 14574A partial specialization of the class template <tt>hash</tt> (20.7.16 [unord.hash]) shall be provided for instances of the 14575<tt>unique_ptr</tt> template suitable for use as a key in unordered 14576associative containers (23.5 [unord]) if and only if there is a 14577<tt>hash</tt> specialization available for the type <tt>D::pointer</tt>. 14578For an object <tt>p</tt> of type <tt>unqiue_ptr<T,D></tt> the 14579<tt>hash</tt> shall evaluate to the same value as <tt>hash<typename 14580D::pointer>{}(p.get())</tt>. 14581</blockquote> 14582 14583<pre>template <class T> struct hash<shared_ptr<T>>; 14584</pre> 14585 14586<blockquote> 14587A partial specialization of the class template <tt>hash</tt> (20.7.16 [unord.hash]) 14588shall be provided for instances of the <tt>shared_ptr</tt> template 14589suitable for use as a key in unordered associative containers 14590(23.5 [unord]). For an object <tt>p</tt> of type <tt>shared_ptr<T></tt> 14591the <tt>hash</tt> shall evaluate 14592to the same value as <tt>hash<T*>{}(p.get())</tt>. 14593</blockquote> 14594</blockquote> 14595 14596 14597 14598 14599 14600<hr> 14601<h3><a name="983"></a>983. <tt>unique_ptr</tt> reference deleters should not be moved from</h3> 14602<p><b>Section:</b> 20.8.14.2 [unique.ptr.single] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 14603 <b>Submitter:</b> Howard Hinnant <b>Opened:</b> 2009-02-10 <b>Last modified:</b> 2009-10-21</p> 14604<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#unique.ptr.single">active issues</a> in [unique.ptr.single].</p> 14605<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#unique.ptr.single">issues</a> in [unique.ptr.single].</p> 14606<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 14607<p><b>Discussion:</b></p> 14608<p> 14609Dave brought to my attention that when a <tt>unique_ptr</tt> has a non-const reference 14610type deleter, move constructing from it, even when the <tt>unique_ptr</tt> containing 14611the reference is an rvalue, could have surprising results: 14612</p> 14613 14614<blockquote><pre>D d(some-state); 14615unique_ptr<A, D&> p(new A, d); 14616unique_ptr<A, D> p2 = std::move(p); 14617<font color="#c80000">// has d's state changed here?</font> 14618</pre></blockquote> 14619 14620<p> 14621I agree with him. It is the <tt>unique_ptr</tt> that is the rvalue, not the 14622deleter. When the deleter is a reference type, the <tt>unique_ptr</tt> should 14623respect the "lvalueness" of the deleter. 14624</p> 14625 14626<p> 14627Thanks Dave. 14628</p> 14629 14630<p><i>[ 14631Batavia (2009-05): 14632]</i></p> 14633 14634<blockquote> 14635Seems correct, but complicated enough that we recommend moving to Review. 14636</blockquote> 14637 14638<p><i>[ 146392009-10 Santa Cruz: 14640]</i></p> 14641 14642 14643<blockquote> 14644Move to Ready. 14645</blockquote> 14646 14647 14648 14649<p><b>Proposed resolution:</b></p> 14650<p> 14651Change 20.8.14.2.1 [unique.ptr.single.ctor], p20-21 14652</p> 14653 14654<blockquote> 14655<pre>template <class U, class E> unique_ptr(unique_ptr<U, E>&& u); 14656</pre> 14657 14658<blockquote> 14659 14660<p> 14661-20- <i>Requires:</i> If <tt><del>D</del> <ins>E</ins></tt> is not a reference type, 14662construction of the deleter <tt>D</tt> from an rvalue of type <tt>E</tt> 14663shall be well formed and shall not throw an exception. 14664<ins> 14665Otherwise <tt>E</tt> is a reference type and construction of the deleter 14666<tt>D</tt> from an lvalue of type <tt>E</tt> shall be well formed and 14667shall not throw an exception. 14668</ins> 14669If <tt>D</tt> is 14670a reference type, then <tt>E</tt> shall be the same type as <tt>D</tt> 14671(diagnostic required). <tt>unique_ptr<U, E>::pointer</tt> shall be 14672implicitly convertible to <tt>pointer</tt>. [<tt>Note:</tt> These 14673requirements imply that <tt>T</tt> and <tt>U</tt> are complete types. 14674<i>-- end note</i>] 14675</p> 14676 14677<p> 14678-21- <i>Effects:</i> Constructs a <tt>unique_ptr</tt> which owns the 14679pointer which <tt>u</tt> owns (if any). If the deleter 14680<ins><tt>E</tt></ins> is not a reference type, <del>it</del> <ins>this 14681deleter</ins> is move constructed from <tt>u</tt>'s deleter, otherwise 14682<del>the reference</del> <ins>this deleter</ins> is copy constructed 14683from <tt>u</tt>.'s deleter. After the construction, <tt>u</tt> no longer 14684owns a pointer. [<i>Note:</i> The deleter constructor can be implemented 14685with <tt>std::forward<<del>D</del><ins>E</ins>></tt>. <i>-- end 14686note</i>] 14687</p> 14688 14689</blockquote> 14690</blockquote> 14691 14692<p> 14693Change 20.8.14.2.3 [unique.ptr.single.asgn], p1-3 14694</p> 14695 14696<blockquote> 14697<pre>unique_ptr& operator=(unique_ptr&& u); 14698</pre> 14699<blockquote> 14700 14701<p> 14702-1- <i>Requires:</i> <ins>If the deleter <tt>D</tt> is not a reference type,</ins> 14703<del>A</del><ins>a</ins>ssignment of the deleter <tt>D</tt> from an rvalue <tt>D</tt> shall not throw an exception. 14704<ins> 14705Otherwise the deleter <tt>D</tt> is a reference type, 14706and assignment of the deleter <tt>D</tt> from an lvalue <tt>D</tt> shall not throw an exception.</ins> 14707</p> 14708 14709<p> 14710-2- <i>Effects:</i> reset(u.release()) followed by 14711a<ins>n</ins> <del>move</del> assignment from <del><tt>u</tt>'s deleter to this deleter</del> 14712<ins><tt>std::forward<D>(u.get_deleter())</tt></ins>. 14713</p> 14714 14715<p> 14716-3- <i>Postconditions:</i> This <tt>unique_ptr</tt> now owns the pointer 14717which <tt>u</tt> owned, and <tt>u</tt> no longer owns it. <del>[<i>Note:</i> If 14718<tt>D</tt> is a reference type, then the referenced lvalue deleters are 14719move assigned. <i>-- end note</i>]</del> 14720</p> 14721</blockquote> 14722</blockquote> 14723 14724<p> 14725Change 20.8.14.2.3 [unique.ptr.single.asgn], p6-7 14726</p> 14727 14728<blockquote> 14729<pre>template <class U, class E> unique_ptr& operator=(unique_ptr<U, E>&& u); 14730</pre> 14731<blockquote> 14732 14733<p> 14734<i>Requires:</i> <ins>If the deleter <tt>E</tt> is not a reference type,</ins> 14735<del>A</del><ins>a</ins>ssignment of the deleter <tt>D</tt> from an rvalue 14736<tt><del>D</del><ins>E</ins></tt> shall not throw an exception. 14737<ins> 14738Otherwise the deleter <tt>E</tt> is a reference type, 14739and assignment of the deleter <tt>D</tt> from an lvalue <tt>E</tt> shall not throw an exception.</ins> 14740<tt>unique_ptr<U, E>::pointer</tt> shall be implicitly convertible to <tt>pointer</tt>. 14741[<i>Note:</i> These requirements imply that <tt>T</tt> and <tt>U></tt> 14742are complete types. <i>-- end note</i>] 14743</p> 14744 14745<p> 14746<i>Effects:</i> <tt>reset(u.release())</tt> followed by 14747a<ins>n</ins> <del>move</del> assignment from <del><tt>u</tt>'s deleter to this deleter</del> 14748<ins><tt>std::forward<E>(u.get_deleter())</tt></ins>. 14749<del>If either 14750<tt>D</tt> or <tt>E</tt> is a reference type, then the referenced lvalue 14751deleter participates in the move assignment.</del> 14752</p> 14753 14754</blockquote> 14755</blockquote> 14756 14757 14758 14759 14760 14761 14762<hr> 14763<h3><a name="985"></a>985. Allowing throwing move</h3> 14764<p><b>Section:</b> 23.2.1 [container.requirements.general] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 14765 <b>Submitter:</b> Rani Sharoni <b>Opened:</b> 2009-02-12 <b>Last modified:</b> 2009-10-20</p> 14766<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#container.requirements.general">active issues</a> in [container.requirements.general].</p> 14767<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#container.requirements.general">issues</a> in [container.requirements.general].</p> 14768<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 14769<p><b>Discussion:</b></p> 14770<p> 14771<b>Introduction</b> 14772</p> 14773 14774<p>This proposal is meant to resolve potential regression of the 14775<a href="" ref="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2800.pdf">N2800</a> 14776draft, see 14777next section, and to relax the requirements for containers of types with 14778throwing move constructors.</p> 14779 14780<p>The basic problem is that some containers operations, like <tt>push_back</tt>, 14781have a strong exception safety 14782guarantee (i.e. no side effects upon exception) that are not achievable when 14783throwing move constructors are used since there is no way to guarantee revert 14784after partial move. For such operations the implementation can at most provide 14785the basic guarantee (i.e. valid but unpredictable) as it does with multi 14786copying operations (e.g. range insert).</p> 14787 14788<p>For example, <tt>vector<T>::push_back()</tt> (where <tt>T</tt> has a move 14789constructor) might resize the <tt>vector</tt> and move the objects to the new underlying 14790buffer. If move constructor throws it might 14791not be possible to recover the throwing object or to move the old objects back to 14792the original buffer.</p> 14793 14794<p>The current draft is explicit by disallowing throwing move 14795for some operations (e.g. <tt>vector<>::reserve</tt>) and not clear about other 14796operations mentioned in 23.2.1 [container.requirements.general]/10 14797(e.g. single element <tt>insert</tt>): it guarantees strong exception 14798safety without explicitly disallowing a throwing move constructor. 14799</p> 14800 14801<p> 14802<b>Regression</b> 14803</p> 14804 14805<p>This section only refers to cases in which the contained object 14806is by itself a standard container.</p> 14807 14808<p>Move constructors of standard containers are allowed to throw and therefore 14809existing operations are broken, compared with C++03, due to move optimization. 14810(In fact existing implementations like Dinkumware are actually throwing).</p> 14811 14812<p>For example, <tt>vector< list<int> >::reserve</tt> yields 14813undefined behavior since <tt>list<int></tt>'s move constructor is allowed to throw. 14814On the other hand, the same operation has strong exception safety guarantee in 14815C++03.</p> 14816 14817<p>There are few options to solve this regression:</p> 14818 14819<ol> 14820<li> 14821Disallow throwing move and throwing default constructor 14822</li> 14823 14824<li> 14825Disallow throwing move but disallowing usage after move 14826</li> 14827 14828<li> 14829Special casing 14830</li> 14831 14832<li> 14833Disallow throwing move and making it optional 14834</li> 14835 14836</ol> 14837 14838<p>Option 1 is suggested by proposal 14839<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2815.html">N2815</a> 14840but it might not be applicable for existing implementations for which 14841containers default constructors are throwing.</p> 14842 14843<p>Option 2 limits the usage significantly and it's error prone 14844by allowing zombie objects that are nothing but destructible (e.g. no <tt>clear()</tt> 14845is allowed after move). It also potentially complicates the implementation by 14846introducing special state.</p> 14847 14848<p>Option 3 is possible, for example, using default 14849construction and <tt>swap</tt> instead of move for standard containers case. The 14850implementation is also free to provide special hidden operation for non 14851throwing move without forcing the user the cope with the limitation of option-2 14852when using the public move.</p> 14853 14854<p>Option 4 impact the efficiency in all use cases due to rare throwing move.</p> 14855 14856<p>The proposed wording will imply option 1 or 3 though option 2 is also 14857achievable using more wording. I personally oppose to option 2 that has impact 14858on usability.</p> 14859 14860<p> 14861<b>Relaxation for user types</b> 14862</p> 14863 14864<p>Disallowing throwing move constructors in general seems very restrictive 14865since, for example, common implementation of move will be default construction 14866+ <tt>swap</tt> so move will throw if the 14867default constructor will throw. This is currently the case with the Dinkumware 14868implementation of node based containers (e.g. <tt>std::list</tt>) 14869though this section doesn't refer to standard types.</p> 14870 14871<p>For throwing move constructors it seem that the implementation should have 14872no problems to provide the basic guarantee instead of the strong one. It's 14873better to allow throwing move constructors with basic guarantee than to 14874disallow it silently (compile and run), via undefined behavior.</p> 14875 14876<p>There might still be cases in which the relaxation will break existing generic 14877code that assumes the strong guarantee but it's broken either way given a 14878throwing move constructor since this is not a preserving optimization. </p> 14879 14880<p><i>[ 14881Batavia (2009-05): 14882]</i></p> 14883 14884<blockquote> 14885<p> 14886Bjarne comments (referring to his draft paper): 14887"I believe that my suggestion simply solves that. 14888Thus, we don't need a throwing move." 14889</p> 14890<p> 14891Move to Open and recommend it be deferred until after the next 14892Committee Draft is issued. 14893</p> 14894</blockquote> 14895 14896<p><i>[ 148972009-10 Santa Cruz: 14898]</i></p> 14899 14900 14901<blockquote> 14902Should wait to get direction from Dave/Rani 14903(<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2983.html">N2983</a>). 14904</blockquote> 14905 14906 14907 14908<p><b>Proposed resolution:</b></p> 14909 14910<p> 1491123.2.1 [container.requirements.general] paragraph 10 add footnote: 14912</p> 14913 14914<blockquote> 14915<p> 14916-10- Unless otherwise specified (see 23.1.4.1, 23.1.5.1, 23.2.2.3, and 1491723.2.6.4) all container types defined in this Clause meet the following 14918additional requirements: 14919</p> 14920<ul> 14921<li>...</li> 14922</ul> 14923 14924<p> 14925<ins>[<i>Note</i>: for compatibility with C++ 149262003, when "no effect" is required, standard containers should not use the 14927value_type's throwing move constructor when the contained object is by itself a 14928standard container. -- <i>end note</i>]</ins> 14929</p> 14930 14931</blockquote> 14932 14933<p>23.2.5.1 [unord.req.except] change paragraph 2 to say: </p> 14934 14935<blockquote> 14936<p> 14937-2- For unordered associative containers, if an exception is 14938thrown by any operation other than the container's hash function from within an 14939<tt>insert()</tt> function inserting a single element, the <tt>insert()</tt> 14940function has no effect<ins> unless the exception is thrown by the contained 14941object move constructor</ins>. 14942</p> 14943 14944<p> 14945-4- For unordered associative containers, if an exception is 14946thrown from within a <tt>rehash()</tt> function other than by the container's hash 14947function or comparison function, the <tt>rehash()</tt> function has no effect 14948<ins>unless the exception is thrown by the contained 14949object move constructor</ins>.</p> 14950 14951</blockquote> 14952 14953<p> 1495423.3.2.3 [deque.modifiers] change paragraph 2 to say: 14955</p> 14956 14957<blockquote> 14958-2- <i>Remarks:</i> If an exception is thrown other than by 14959the copy constructor<ins>, move constructor</ins> 14960or assignment operator of <tt>T</tt> 14961there are no effects. 14962<ins>If an exception is thrown by <tt>push_back()</tt> or <tt>emplace_back()</tt> 14963function, that function has no effects unless the exception is thrown by 14964the move constructor of <tt>T</tt>.</ins> 14965</blockquote> 14966 14967<p> 1496823.3.2.3 [deque.modifiers] change paragraph 6 to say: 14969</p> 14970 14971<blockquote> 14972-6- <i>Throws:</i> Nothing unless an exception is thrown by the copy 14973constructor<ins>, move constructor</ins> or assignment operator of <tt>T</tt>. 14974</blockquote> 14975 14976<p> 1497723.3.6.2 [vector.capacity] remove paragraph 2 14978</p> 14979 14980<blockquote> 14981<del>-2- <i>Requires:</i> If <tt>value_type</tt> has a move constructor, 14982that constructor shall not throw any exceptions.</del> 14983</blockquote> 14984 14985<p> 1498623.3.6.2 [vector.capacity] paragraph 3 change to say: 14987</p> 14988 14989<blockquote> 14990-3- <i>Effects:</i> A directive that informs a <tt>vector</tt> 14991of a planned change in size, so 14992that it can manage the storage allocation accordingly. After <tt>reserve()</tt>, 14993<tt>capacity()</tt> is greater or equal to the argument of <tt>reserve</tt> 14994if reallocation happens; and equal 14995to the previous value of <tt>capacity()</tt> 14996otherwise. Reallocation happens at this point if and only if the current 14997capacity is less than the argument of <tt>reserve()</tt>. 14998If an exception is thrown, there are no effects<ins> 14999unless the exception is thrown by the contained object move constructor</ins>. 15000</blockquote> 15001 15002<p> 1500323.3.6.2 [vector.capacity] paragraph 12 change to say: 15004</p> 15005 15006<blockquote> 15007-12- <i>Requires:</i> <del>If <tt>value_type</tt> has a move constructor, 15008that constructor shall not throw any exceptions.</del> 15009<ins>If an exception is thrown, there are no effects unless the exception is thrown by 15010the contained object move constructor.</ins> 15011</blockquote> 15012 15013<p> 1501423.3.6.4 [vector.modifiers] change paragraph 1 to say: 15015</p> 15016 15017<blockquote> 15018-1- <del><i>Requires:</i> If <tt>value_type</tt> has a move constructor, 15019that constructor shall not throw any exceptions.</del> 15020<ins><i>Remarks:</i> If an exception is thrown by <tt>push_back()</tt> 15021or <tt>emplace_back()</tt> function, that function has no effect unless the 15022exception is thrown by the move constructor of <tt>T</tt>.</ins> 15023</blockquote> 15024 15025<p> 1502623.3.6.4 [vector.modifiers] change paragraph 2 to say: 15027</p> 15028 15029<blockquote> 15030-2- <i>Remarks:</i> Causes reallocation if the new size is greater than 15031the old capacity. If no reallocation happens, all the iterators and 15032references before the insertion point remain valid. If an exception is 15033thrown other than by the copy constructor<ins>, move constructor</ins> 15034or assignment operator of <tt>T</tt> or by any <tt>InputIterator</tt> 15035operation there are no effects. 15036</blockquote> 15037 15038<p> 1503923.3.6.4 [vector.modifiers] change paragraph 6 to say: 15040</p> 15041 15042<blockquote> 15043-6- <i>Throws:</i> Nothing unless an exception is thrown by the copy 15044constructor<ins>, move constructor</ins> or assignment operator of <tt>T</tt>. 15045</blockquote> 15046 15047 15048 15049 15050 15051 15052<hr> 15053<h3><a name="987"></a>987. <tt>reference_wrapper</tt> and function types</h3> 15054<p><b>Section:</b> 20.7.5 [refwrap] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Tentatively Ready</a> 15055 <b>Submitter:</b> Howard Hinnant <b>Opened:</b> 2009-02-18 <b>Last modified:</b> 2009-10-26</p> 15056<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#refwrap">issues</a> in [refwrap].</p> 15057<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20Ready">Tentatively Ready</a> status.</p> 15058<p><b>Discussion:</b></p> 15059<p> 15060The synopsis in 20.7.5 [refwrap] says: 15061</p> 15062 15063<blockquote><pre>template <<b>ObjectType</b> T> class reference_wrapper 15064... 15065</pre></blockquote> 15066 15067<p> 15068And then paragraph 3 says: 15069</p> 15070 15071<blockquote> 15072<p> 15073The template instantiation <tt>reference_wrapper<T></tt> shall be 15074derived from <tt>std::unary_function<T1, R></tt> only if the type 15075<tt>T</tt> is any of the following: 15076</p> 15077 15078<ul> 15079<li> 15080a <b>function type</b> or a pointer to function type taking one argument of 15081type <tt>T1</tt> and returning <tt>R</tt> 15082</li> 15083</ul> 15084</blockquote> 15085 15086<p> 15087But function types are not <tt>ObjectType</tt>s. 15088</p> 15089 15090<p> 15091Paragraph 4 contains the same contradiction. 15092</p> 15093 15094<p><i>[ 15095Post Summit: 15096]</i></p> 15097 15098 15099<blockquote> 15100<p> 15101Jens: restricted reference to ObjectType 15102</p> 15103<p> 15104Recommend Review. 15105</p> 15106</blockquote> 15107 15108<p><i>[ 15109Post Summit, Peter adds: 15110]</i></p> 15111 15112 15113<blockquote> 15114<p> 15115In <a href="https://svn.boost.org/trac/boost/ticket/1846">https://svn.boost.org/trac/boost/ticket/1846</a> 15116however Eric Niebler makes the very reasonable point that <tt>reference_wrapper<F></tt>, 15117where <tt>F</tt> is a function type, represents a reference to a function, 15118a legitimate entity. So <tt>boost::ref</tt> was changed to allow it. 15119</p> 15120<p> 15121<a href="https://svn.boost.org/trac/boost/browser/trunk/libs/bind/test/ref_fn_test.cpp">https://svn.boost.org/trac/boost/browser/trunk/libs/bind/test/ref_fn_test.cpp</a> 15122</p> 15123<p> 15124Therefore, I believe an alternative proposed resolution for issue 987 could simply 15125allow <tt>reference_wrapper</tt> to be used with function types. 15126</p> 15127</blockquote> 15128 15129<p><i>[ 15130Post Summit, Howard adds: 15131]</i></p> 15132 15133 15134<blockquote> 15135<p> 15136I agree with Peter (and Eric). I got this one wrong on my first try. Here 15137is code that demonstrates how easy (and useful) it is to instantiate 15138<tt>reference_wrapper</tt> with a function type: 15139</p> 15140 15141<blockquote><pre>#include <functional> 15142 15143template <class F> 15144void test(F f); 15145 15146void f() {} 15147 15148int main() 15149{ 15150 test(std::ref(f)); 15151} 15152</pre></blockquote> 15153 15154<p> 15155Output (link time error shows type of <tt>reference_wrapper</tt> instantiated 15156with function type): 15157</p> 15158 15159<blockquote><pre>Undefined symbols: 15160 "void test<std::reference_wrapper<void ()()> >(std::reference_wrapper<void ()()>)",... 15161</pre></blockquote> 15162 15163<p> 15164I've taken the liberty of changing the proposed wording to allow function types 15165and set to Open. I'll also freely admit that I'm not positive <tt>ReferentType</tt> 15166is the correct concept. 15167</p> 15168 15169</blockquote> 15170 15171 15172 15173<p><i>[ 15174Batavia (2009-05): 15175]</i></p> 15176 15177<blockquote> 15178<p> 15179Howard observed that <tt>FunctionType</tt>, 15180a concept not (yet?) in the Working Paper, 15181is likely the correct constraint to be applied. 15182However, the proposed resolution provides an adequate approximation. 15183</p> 15184<p> 15185Move to Review. 15186</p> 15187</blockquote> 15188 15189<p><i>[ 151902009-05-23 Alisdair adds: 15191]</i></p> 15192 15193 15194<blockquote> 15195<p> 15196By constraining to <tt>PointeeType</tt> we rule out the ability for <tt>T</tt> to be a 15197reference, and call in reference-collapsing. I'm not sure if this is 15198correct and intended, but would like to be sure the case was considered. 15199</p> 15200<p> 15201Is dis-allowing reference types and the 15202implied reference collapsing the intended result? 15203</p> 15204</blockquote> 15205 15206<p><i>[ 152072009-07 Frankfurt 15208]</i></p> 15209 15210 15211<blockquote> 15212Moved from Review to Open only because the wording needs to be 15213tweaked for concepts removal. 15214</blockquote> 15215 15216<p><i>[ 152172009-10-14 Daniel provided de-conceptified wording. 15218]</i></p> 15219 15220 15221<p><i>[ 152222009-10 post-Santa Cruz: 15223]</i></p> 15224 15225 15226<blockquote> 15227Move to Tentatively Ready. 15228</blockquote> 15229 15230 15231 15232<p><b>Proposed resolution:</b></p> 15233<p> 15234Change 20.7.5 [refwrap]/1 as indicated: 15235</p> 15236 15237<blockquote> 15238<tt>reference_wrapper<T></tt> is a <tt>CopyConstructible</tt> and 15239<tt><ins>Copy</ins>Assignable</tt> wrapper around a 15240reference to an object <ins>or function</ins> of type <tt>T</tt>. 15241</blockquote> 15242 15243 15244 15245 15246 15247<p><b>Rationale:</b></p> 15248<p> 15249a) The occurrence of <tt>T&</tt> in the function signature auto-implies 15250<tt>std::ReferentType</tt>, 15251this is due to [temp.req.impl]/4 bullet 4 15252</p> 15253<p> 15254b) The occurrence of the constrained template <tt>reference_wrapper<T></tt> in 15255the remaining 15256signatures lets kick in [temp.req.impl]/4 bullet 1 and adds *all* requirements of 15257this template. But we need to add at least *one* requirement (and it 15258was an arbitrary, 15259but natural decision to require <tt>std::PointeeType</tt> here) to *activate* 15260this. If we hadn't done 15261this, we were in unconstrained mode! 15262</p> 15263 15264 15265 15266 15267 15268<hr> 15269<h3><a name="996"></a>996. Move operation not well specified</h3> 15270<p><b>Section:</b> 17 [library] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 15271 <b>Submitter:</b> David Abrahams <b>Opened:</b> 2009-03-06 <b>Last modified:</b> 2009-05-23</p> 15272<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#library">active issues</a> in [library].</p> 15273<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#library">issues</a> in [library].</p> 15274<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 15275<p><b>Discussion:</b></p> 15276<p> 15277There are lots of places in the standard where we talk about "the move 15278constructor" but where we mean "the move operation," i.e. <tt>T( move( x ) )</tt>. 15279</p> 15280<p> 15281We also don't account for whether that operation modifies <tt>x</tt> or not, and 15282we need to. 15283</p> 15284 15285<p><i>[ 15286Batavia (2009-05): 15287]</i></p> 15288 15289<blockquote> 15290Move to Open, pending proposed wording from Dave for further 15291review. 15292</blockquote> 15293 15294 15295<p><b>Proposed resolution:</b></p> 15296<p> 15297</p> 15298 15299 15300 15301 15302 15303<hr> 15304<h3><a name="999"></a>999. Taking the address of a function</h3> 15305<p><b>Section:</b> 20.8.13 [specialized.algorithms] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Tentatively Ready</a> 15306 <b>Submitter:</b> Peter Dimov <b>Opened:</b> 2009-03-09 <b>Last modified:</b> 2009-10-26</p> 15307<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#specialized.algorithms">issues</a> in [specialized.algorithms].</p> 15308<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20Ready">Tentatively Ready</a> status.</p> 15309<p><b>Discussion:</b></p> 15310<p> 15311The same fix (reference <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#987">987</a>) may be applied to <tt>addressof</tt>, which is also constrained to 15312<tt>ObjectType</tt>. (That was why <tt>boost::ref</tt> didn't work with functions - it 15313tried to apply <tt>boost::addressof</tt> and the <tt>reinterpret_cast<char&></tt> 15314implementation of <tt>addressof</tt> failed.) 15315</p> 15316 15317 15318 15319<p><i>[ 15320Batavia (2009-05): 15321]</i></p> 15322 15323<blockquote> 15324<p> 15325We agree. 15326</p> 15327<p> 15328Move to Tentatively Ready. 15329</p> 15330</blockquote> 15331 15332<p><i>[ 153332009-07 Frankfurt 15334]</i></p> 15335 15336 15337<blockquote> 15338Moved from Tentatively Ready to Open only because the wording needs to be 15339tweaked for concepts removal. 15340</blockquote> 15341 15342<p><i>[ 153432009-10-10 Daniel updates wording to concept-free. 15344]</i></p> 15345 15346 15347<p><i>[ 153482009-10 post-Santa Cruz: 15349]</i></p> 15350 15351 15352<blockquote> 15353Move to Tentatively Ready. 15354</blockquote> 15355 15356 15357 15358<p><b>Proposed resolution:</b></p> 15359<p><i>[ 15360The resolution assumes that <tt>addressof</tt> is reintroduced as described in 15361<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2946.pdf">n2946</a> 15362]</i></p> 15363 15364 15365<p> 15366In 20.8.13 [specialized.algorithms] change as described: 15367</p> 15368 15369<blockquote><pre>template <class T> T* addressof(T& r); 15370</pre> 15371<blockquote> 15372<i>Returns:</i> The actual address of the object <ins>or function</ins> 15373referenced by <tt>r</tt>, even in the 15374presence of an overloaded <tt>operator&</tt>. 15375</blockquote> 15376</blockquote> 15377 15378 15379 15380 15381<p><b>Rationale:</b></p> 15382<p> 15383a) The occurrence of <tt>T&</tt> in the function signature auto-implies 15384<tt>std::ReferentType</tt>, 15385this is due to [temp.req.impl]/4 bullet 4 15386</p> 15387 15388 15389 15390 15391 15392<hr> 15393<h3><a name="1008"></a>1008. <tt>nested_exception</tt> wording unclear</h3> 15394<p><b>Section:</b> 18.8.6 [except.nested] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 15395 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-03-11 <b>Last modified:</b> 2009-10-22</p> 15396<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#except.nested">active issues</a> in [except.nested].</p> 15397<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#except.nested">issues</a> in [except.nested].</p> 15398<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 15399<p><b>Discussion:</b></p> 15400 15401<p><b>Addresses JP 31</b></p> 15402 15403<p> 15404It is difficult to understand in which case <tt>nested_exception</tt> is applied. 15405</p> 15406 15407<p><i>[ 15408Summit: 15409]</i></p> 15410 15411 15412<blockquote> 15413Alisdair will add an example in an update to 15414<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2619.pdf">N2619</a>. 15415</blockquote> 15416 15417<p><i>[ 154182009-10 Santa Cruz: 15419]</i></p> 15420 15421 15422<blockquote> 15423It doesn't appear that N2619 really addresses this. Alisdair to propose wording. 15424</blockquote> 15425 15426 15427 15428<p><b>Proposed resolution:</b></p> 15429 15430 15431 15432 15433 15434<hr> 15435<h3><a name="1011"></a>1011. <tt>next/prev</tt> wrong iterator type</h3> 15436<p><b>Section:</b> 24.4.4 [iterator.operations] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 15437 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-03-11 <b>Last modified:</b> 2009-10-22</p> 15438<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#iterator.operations">active issues</a> in [iterator.operations].</p> 15439<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#iterator.operations">issues</a> in [iterator.operations].</p> 15440<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 15441<p><b>Discussion:</b></p> 15442 15443<p><b>Addresses UK 271</b></p> 15444 15445<p> 15446<tt>next/prev</tt> return an incremented iterator without changing the value of 15447the original iterator. However, even this may invalidate an 15448<tt>InputIterator</tt>. A <tt>ForwardIterator</tt> is required to guarantee the 15449'multipass' property. 15450</p> 15451 15452<p><i>[ 15453Batavia (2009-05): 15454]</i></p> 15455 15456<blockquote> 15457We agree with the proposed resolution. 15458Move to Tentatively Ready. 15459</blockquote> 15460 15461<p><i>[ 154622009-07 Frankfurt 15463]</i></p> 15464 15465 15466<blockquote> 15467Moved from Tentatively Ready to Open only because the wording needs to be 15468tweaked for concepts removal. 15469</blockquote> 15470 15471<p><i>[ 154722009-10-14 Daniel provided de-conceptified wording. 15473]</i></p> 15474 15475 15476<p><i>[ 154772009-10 Santa Cruz: 15478]</i></p> 15479 15480 15481<blockquote> 15482Moved to Ready. 15483</blockquote> 15484 15485 15486 15487<p><b>Proposed resolution:</b></p> 15488 15489 15490<ol> 15491<li> 15492<p> 15493Change header <tt><iterator></tt> synopsis 24.3 [iterator.synopsis] as indicated: 15494</p> 15495 15496<blockquote><pre>// 24.4.4, iterator operations: 15497... 15498template <class <del>Input</del><ins>Forward</ins>Iterator> 15499 <del>Input</del><ins>Forward</ins>Iterator 15500 next(<del>Input</del><ins>Forward</ins>Iterator x, typename std::iterator_traits<<del>Input</del><ins>Forward</ins>Iterator>::difference_type n = 1); 15501</pre></blockquote> 15502</li> 15503 15504<li> 15505<p> 15506Change 24.4.4 [iterator.operations] before p.6 as indicated: 15507</p> 15508 15509<blockquote><pre>template <class <del>Input</del><ins>Forward</ins>Iterator> 15510 <del>Input</del><ins>Forward</ins>Iterator 15511 next(<del>Input</del><ins>Forward</ins>Iterator x, typename std::iterator_traits<<del>Input</del><ins>Forward</ins>Iterator>::difference_type n = 1); 15512</pre></blockquote> 15513</li> 15514</ol> 15515 15516 15517 15518 15519 15520 15521<hr> 15522<h3><a name="1030"></a>1030. Response to JP 44</h3> 15523<p><b>Section:</b> 20.8.15.5 [util.smartptr.shared.atomic] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 15524 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-03-11 <b>Last modified:</b> 2009-10-23</p> 15525<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 15526<p><b>Discussion:</b></p> 15527 15528<p><b>Addresses JP 44</b></p> 15529 15530<p> 15531The 1st parameter <tt>p</tt> and 2nd parameter <tt>v</tt> is now 15532<tt>shared_ptr<T>*</tt>. 15533</p> 15534<p> 15535It should be <tt>shared_ptr<T>&</tt>, or if these are 15536<tt>shared_ptr<T>*</tt> then add the "<tt>p</tt> shall not be a 15537null pointer" at the requires. 15538</p> 15539 15540<p><i>[ 15541Summit: 15542]</i></p> 15543 15544 15545<blockquote> 15546Agree. All of the functions need a requirement that <tt>p</tt> (or 15547<tt>v</tt>) is a pointer to a valid object. 15548</blockquote> 15549 15550<p><i>[ 155512009-07 post-Frankfurt: 15552]</i></p> 15553 15554 15555<blockquote> 15556<p> 15557Lawrence explained that these signatures match the regular atomics. The 15558regular atomics must not use references because these signatures are 15559shared with C. The decision to pass shared_ptrs by pointer rather than 15560by reference was deliberate and was motivated by the principle of least 15561surprise. 15562</p> 15563<p> 15564Lawrence to write wording that requires that the pointers not be null. 15565</p> 15566</blockquote> 15567 15568<p><i>[ 155692009-09-20 Lawrence provided wording: 15570]</i></p> 15571 15572 15573<blockquote> 15574<p> 15575The parameter types for atomic shared pointer access 15576were deliberately chosen to be pointers 15577to match the corresponding parameters of the atomics chapter. 15578Those in turn were deliberately chosen 15579to match C functions, 15580which do not have reference parameters. 15581</p> 15582<p> 15583We adopt the second suggestion, 15584to require that such pointers not be null. 15585</p> 15586</blockquote> 15587 15588<p><i>[ 155892009-10 Santa Cruz: 15590]</i></p> 15591 15592 15593<blockquote> 15594Moved to Ready. 15595</blockquote> 15596 15597 15598 15599<p><b>Proposed resolution:</b></p> 15600<p> 15601In section "<code>shared_ptr</code> atomic access" 1560220.8.15.5 [util.smartptr.shared.atomic], add to each function the 15603following clause. 15604</p> 15605<blockquote><p> 15606<i>Requires:</i> <code>p</code> shall not be null. 15607</p></blockquote> 15608 15609 15610 15611 15612 15613<hr> 15614<h3><a name="1033"></a>1033. <tt>thread::join()</tt> effects?</h3> 15615<p><b>Section:</b> 30.3.1.5 [thread.thread.member] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 15616 <b>Submitter:</b> Alberto Ganesh Barbati <b>Opened:</b> 2009-03-12 <b>Last modified:</b> 2009-05-23</p> 15617<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#thread.thread.member">active issues</a> in [thread.thread.member].</p> 15618<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#thread.thread.member">issues</a> in [thread.thread.member].</p> 15619<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 15620<p><b>Discussion:</b></p> 15621 15622<p> 15623While looking at <tt>thread::join()</tt> I think I spotted a couple of 15624possible defects in the specifications. I could not find a previous 15625issue or NB comment about that, but I might have missed it. 15626</p> 15627 15628<p> 15629The postconditions clause for <tt>thread::join()</tt> is: 15630</p> 15631 15632<blockquote> 15633<i>Postconditions:</i> If <tt>join()</tt> throws an exception, the value 15634returned by <tt>get_id()</tt> is unchanged. Otherwise, <tt>get_id() == id()</tt>. 15635</blockquote> 15636 15637<p> 15638and the throws clause is: 15639</p> 15640 15641<blockquote> 15642<i>Throws:</i> <tt>std::system_error</tt> when the postconditions cannot be achieved. 15643</blockquote> 15644 15645<p> 15646Now... how could the postconditions <em>not</em> be achieved? 15647It's just a matter of resetting the value of <tt>get_id()</tt> or leave it 15648unchanged! I bet we can always do that. Moreover, it's a chicken-and-egg 15649problem: in order to decide whether to throw or not I depend on the 15650postconditions, but the postconditions are different in the two cases. 15651</p> 15652 15653<p> 15654I believe the throws clause should be: 15655</p> 15656 15657<blockquote> 15658<i>Throws:</i> <tt>std::system_error</tt> when the effects or postconditions 15659cannot be achieved. 15660</blockquote> 15661 15662<p> 15663as it is in <tt>detach()</tt>, or, even better, as the postcondition is 15664trivially satisfiable and to remove the circular dependency: 15665</p> 15666 15667 15668<blockquote> 15669<i>Throws:</i> <tt>std::system_error</tt> if the effects cannot be achieved. 15670</blockquote> 15671 15672<p> 15673Problem is that... ehm... <tt>join()</tt> has no "Effects" clause. Is that intentional? 15674</p> 15675 15676<p><i>[ 15677See the thread starting at c++std-lib-23204 for more discussion. 15678]</i></p> 15679 15680 15681<p><i>[ 15682Batavia (2009-05): 15683]</i></p> 15684 15685<blockquote> 15686<p> 15687Pete believes there may be some more general language (in frontmatter) 15688that can address this and related issues such as <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#962">962</a>. 15689</p> 15690<p> 15691Move to Open. 15692</p> 15693</blockquote> 15694 15695 15696<p><b>Proposed resolution:</b></p> 15697 15698 15699 15700 15701 15702<hr> 15703<h3><a name="1034"></a>1034. Response to UK 222</h3> 15704<p><b>Section:</b> 23.2.1 [container.requirements.general] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 15705 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-03-12 <b>Last modified:</b> 2009-10-20</p> 15706<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#container.requirements.general">active issues</a> in [container.requirements.general].</p> 15707<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#container.requirements.general">issues</a> in [container.requirements.general].</p> 15708<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 15709<p><b>Discussion:</b></p> 15710 15711<p><b>Addresses UK 222</b></p> 15712 15713<p> 15714It is not clear what purpose the Requirement tables serve in the 15715Containers clause. Are they the definition of a library Container? Or 15716simply a conventient shorthand to factor common semantics into a single 15717place, simplifying the description of each subsequent container? This 15718becomes an issue for 'containers' like <tt>array</tt>, which does not meet the 15719default-construct-to-empty requirement, or <tt>forward_list</tt> which does not 15720support the size operation. Are these components no longer containers? 15721Does that mean the remaining requirements don't apply? Or are these 15722contradictions that need fixing, despite being a clear design decision? 15723</p> 15724 15725<p> 15726Recommend: 15727</p> 15728 15729<p> 15730Clarify all the tables in 23.2 [container.requirements] are 15731there as a convenience for documentation, rather than a strict set of 15732requirements. Containers should be allowed to relax specific 15733requirements if they call attention to them in their documentation. The 15734introductory text for <tt>array</tt> should be expanded to mention a 15735default constructed <tt>array</tt> is not empty, and 15736<tt>forward_list</tt> introduction should mention it does not provide 15737the required <tt>size</tt> operation as it cannot be implemented 15738efficiently. 15739</p> 15740 15741<p><i>[ 15742Summit: 15743]</i></p> 15744 15745 15746<blockquote> 15747Agree in principle. 15748</blockquote> 15749 15750<p><i>[ 157512009-07 post-Frankfurt: 15752]</i></p> 15753 15754 15755<blockquote> 15756We agree in principle, but we have a timetable. This group feels that 15757the issue should be closed as NAD unless a proposed resolution is 15758submitted prior to the March 2010 meeting. 15759</blockquote> 15760 15761<p><i>[ 157622009-10 Santa Cruz: 15763]</i></p> 15764 15765 15766<blockquote> 15767Looked at this and still intend to close as NAD in March 157682010 unless there is proposed wording that we like. 15769</blockquote> 15770 15771 15772 15773<p><b>Proposed resolution:</b></p> 15774 15775 15776 15777 15778 15779<hr> 15780<h3><a name="1052"></a>1052. Response to UK 281</h3> 15781<p><b>Section:</b> 24.5.1.3.5 [reverse.iter.opref] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 15782 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-03-12 <b>Last modified:</b> 2009-10-22</p> 15783<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 15784<p><b>Discussion:</b></p> 15785 15786<p><b>Addresses UK 281</b></p> 15787 15788<p> 15789The current specification for return value for <tt>reverse_iterator::operator-></tt> 15790will always be a true pointer type, but <tt>reverse_iterator</tt> supports proxy 15791iterators where the pointer type may be some kind of 'smart pointer'. 15792</p> 15793 15794<p><i>[ 15795Summit: 15796]</i></p> 15797 15798 15799<blockquote> 15800<p> 15801<tt>move_iterator</tt> avoids this problem by returning a value of the wrapped 15802Iterator type. 15803study group formed to come up with a suggested resolution. 15804</p> 15805<p> 15806<tt>move_iterator</tt> solution shown in proposed wording. 15807</p> 15808</blockquote> 15809 15810<p><i>[ 158112009-07 post-Frankfurt: 15812]</i></p> 15813 15814 15815<blockquote> 15816Howard to deconceptize. Move to Review after that happens. 15817</blockquote> 15818 15819<p><i>[ 158202009-08-01 Howard deconceptized: 15821]</i></p> 15822 15823 15824<blockquote> 15825</blockquote> 15826 15827<p><i>[ 158282009-10 Santa Cruz: 15829]</i></p> 15830 15831 15832<blockquote> 15833<p> 15834We can't think of any reason we can't just define reverse 15835iterator's pointer types to be the same as the underlying iterator's 15836pointer type, and get it by calling the right arrow directly. 15837</p> 15838<p> 15839Here is the proposed wording that was replaced: 15840</p> 15841<blockquote><pre>template <class Iterator> 15842class reverse_iterator { 15843 ... 15844 typedef <del>typename iterator_traits<</del>Iterator<del>>::pointer</del> pointer; 15845</pre></blockquote> 15846 15847<p> 15848Change 24.5.1.3.5 [reverse.iter.opref]: 15849</p> 15850 15851<blockquote><pre>pointer operator->() const; 15852</pre> 15853<blockquote> 15854<i>Returns:</i> 15855<blockquote><pre><del>&(operator*());</del> 15856<ins>this->tmp = current;</ins> 15857<ins>--this->tmp;</ins> 15858<ins>return this->tmp;</ins> 15859</pre></blockquote> 15860</blockquote> 15861</blockquote> 15862</blockquote> 15863 15864 15865 15866<p><b>Proposed resolution:</b></p> 15867<p> 15868Change 24.5.1.3.5 [reverse.iter.opref]: 15869</p> 15870 15871<blockquote><pre>pointer operator->() const; 15872</pre> 15873<blockquote> 15874<i>Returns:</i> 15875<blockquote><pre><del>&(operator*());</del> 15876<ins>deref_tmp = current; 15877--deref_tmp; 15878return deref_tmp::operator->();</ins> 15879</pre></blockquote> 15880</blockquote> 15881</blockquote> 15882 15883 15884 15885 15886 15887 15888 15889 15890 15891<hr> 15892<h3><a name="1056"></a>1056. Must all Engines and Distributions be Streamable?</h3> 15893<p><b>Section:</b> 26.5 [rand] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">Tentatively NAD</a> 15894 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-03-12 <b>Last modified:</b> 2009-11-03</p> 15895<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#rand">issues</a> in [rand].</p> 15896<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20NAD">Tentatively NAD</a> status.</p> 15897<p><b>Discussion:</b></p> 15898 15899<p> 15900Both the concepts <tt>RandomNumberEngine</tt> and <tt>RandomNumberDistribution</tt> have 15901requirements to be <tt>InputStreamable</tt> and <tt>OutputStreamable</tt>. 15902</p> 15903<p> 15904I have no problems leaving the WP in an inconsistent state on the best-faith 15905assumption these concepts will be provided later, however disagree with the 15906proposers that these constraints are not separable, orthogonal to the basic 15907concepts of generating random number distributions. 15908</p> 15909<p> 15910These constraints should be dropped, and applied to specific algorithms as 15911needed. 15912</p> 15913<p> 15914If a more refined concept (certainly deemed useful by the proposers) is 15915proposed there is no objection, but the basic concept should not require 15916persistence via streaming. 15917</p> 15918 15919<p><i>[ 15920Batavia (2009-05): 15921]</i></p> 15922 15923<blockquote> 15924Move to Open. 15925</blockquote> 15926 15927<p><i>[ 159282009-05-31 Alisdair adds: 15929]</i></p> 15930 15931 15932<blockquote> 15933<p> 15934Working on constraining the stream iterators, I have a few more observations 15935to make on the concepts proposed while constraining the random number 15936facility. 15937</p> 15938<p> 15939While I still believe the concerns are orthogonal, I don't believe the 15940existing constraints go far enough either! The goal we want to achieve is 15941not that a <tt>RandomNumberEngine</tt> / <tt>RandomNumberDistribution</tt> supports the stream 15942operators, but that it is <tt>Serializable</tt>. I.e. there is a relationship 15943between the insert and extract operations that guarantees to restore the 15944state of the original object. This implies a coupling of the concepts 15945together in a broader concept (<tt>Serializable</tt>) with at least one axiom to 15946assert the semantics. 15947</p> 15948<p> 15949One problem is that <tt>istream</tt> and <tt>ostream</tt> may be fundamentally different 15950types, although we can hook a relation if we are prepared to drop down to 15951the <tt>char</tt> type and <tt>char_traits</tt> template parameters. Doing so ties us to a 15952form of serialization that demands implementation via the std iostreams 15953framework, which seems overly prescriptive. I believe the goal is generally 15954to support serialization without regard to how it is expressed - although 15955this is getting even more inventive in terms of concepts we do not have 15956today. 15957</p> 15958</blockquote> 15959 15960<p><i>[ 159612009-11-03 Alisdair adds: 15962]</i></p> 15963 15964 15965<blockquote> 15966<p> 15967I can't find the record in the wiki minutes, but it was agreed at both 15968Frankfurt and Santa Cruz that this issue is NAD. 15969</p> 15970<p> 15971The agreement in SC was that I would provide you with the rationale (see 15972below) to include when moving to NAD. 15973</p> 15974</blockquote> 15975 15976<p><i>[ 159772009-11-03 Howard adds: 15978]</i></p> 15979 15980 15981<blockquote> 15982Moved to Tentatively NAD after 5 positive votes on c++std-lib. 15983</blockquote> 15984 15985 15986<p><b>Proposed resolution:</b></p> 15987 15988 15989<p><b>Rationale:</b></p> 15990<p> 15991The issue suggests a more refined concept should be used if we want to 15992require streaming, to separate concerns from the basic 15993<tt>RandomNumberEngine</tt> behaviour. In Frankfurt it was observed 15994that <tt>RandomNumberEngine</tt> <em>is</em> that more refined concept, 15995and the basic concept used in the framework is 15996<tt>UniformRandomNumberGenerator</tt>, which it refines. 15997</p> 15998 15999<p> 16000We concur, and expect this to have no repurcussions re-writing this 16001clause now concepts are removed. 16002</p> 16003 16004 16005 16006 16007 16008<hr> 16009<h3><a name="1068"></a>1068. class random_device should be movable</h3> 16010<p><b>Section:</b> 26.5.6 [rand.device] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 16011 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-03-18 <b>Last modified:</b> 2009-10-26</p> 16012<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#rand.device">issues</a> in [rand.device].</p> 16013<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 16014<p><b>Discussion:</b></p> 16015 16016<p> 16017class <tt>random_device</tt> should be movable. 16018</p> 16019 16020<p><i>[ 16021Batavia (2009-05): 16022]</i></p> 16023 16024<blockquote> 16025Move to Open, and recommend this issue be deferred until after the next 16026Committee Draft is issued. 16027</blockquote> 16028 16029<p><i>[ 160302009-10 post-Santa Cruz: 16031]</i></p> 16032 16033 16034<blockquote> 16035Leave open. Walter to provide drafting as part of his planned paper. 16036</blockquote> 16037 16038 16039 16040<p><b>Proposed resolution:</b></p> 16041 16042 16043 16044 16045 16046<hr> 16047<h3><a name="1069"></a>1069. class seed_seq should support efficient move operations</h3> 16048<p><b>Section:</b> 26.5.7.1 [rand.util.seedseq] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 16049 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-03-18 <b>Last modified:</b> 2009-10-26</p> 16050<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#rand.util.seedseq">issues</a> in [rand.util.seedseq].</p> 16051<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 16052<p><b>Discussion:</b></p> 16053 16054<p> 16055class <tt>seed_seq</tt> should support efficient move operations. 16056</p> 16057 16058<p><i>[ 16059Batavia (2009-05): 16060]</i></p> 16061 16062<blockquote> 16063Move to Open, and recommend this issue be deferred until after the next 16064Committee Draft is issued. 16065</blockquote> 16066 16067<p><i>[ 160682009-10 post-Santa Cruz: 16069]</i></p> 16070 16071 16072<blockquote> 16073Leave open. Walter to provide drafting as part of his planned paper. 16074</blockquote> 16075 16076 16077 16078<p><b>Proposed resolution:</b></p> 16079 16080 16081 16082 16083 16084<hr> 16085<h3><a name="1071"></a>1071. is_bind_expression should derive from integral_constant<bool></h3> 16086<p><b>Section:</b> 20.7.11.1.1 [func.bind.isbind] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Tentatively Ready</a> 16087 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-03-19 <b>Last modified:</b> 2009-10-26</p> 16088<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20Ready">Tentatively Ready</a> status.</p> 16089<p><b>Discussion:</b></p> 16090 16091<p> 16092Class template is_bind_expression 20.7.11.1.1 [func.bind.isbind]: 16093</p> 16094 16095<blockquote><pre>namespace std { 16096 template<class T> struct is_bind_expression { 16097 static const bool value = see below; 16098 }; 16099} 16100</pre></blockquote> 16101<p> 16102<tt>is_bind_expression</tt> should derive from <tt>std::integral_constant<bool></tt> like 16103other similar trait types. 16104</p> 16105 16106<p><i>[ 16107Daniel adds: 16108]</i></p> 16109 16110<blockquote> 16111We need the same thing for the trait <tt>is_placeholder</tt> as well. 16112</blockquote> 16113<p><i>[ 161142009-03-22 Daniel provided wording. 16115]</i></p> 16116 16117 16118<p><i>[ 16119Batavia (2009-05): 16120]</i></p> 16121 16122<blockquote> 16123<p> 16124We recommend this be deferred until after the next Committee Draft is issued. 16125</p> 16126<p> 16127Move to Open. 16128</p> 16129</blockquote> 16130 16131<p><i>[ 161322009-05-31 Peter adds: 16133]</i></p> 16134 16135 16136<blockquote> 16137<p> 16138I am opposed to the proposed resolution and to the premise of the issue 16139in general. The traits's default definitions should NOT derive from 16140<tt>integral_constant</tt>, because this is harmful, as it misleads people into 16141thinking that <tt>is_bind_expression<E></tt> always derives from 16142<tt>integral_constant</tt>, whereas it may not. 16143</p> 16144<p> 16145<tt>is_bind_expression</tt> and <tt>is_placeholder</tt> allow user 16146specializations, and in fact, this is their primary purpose. Such user 16147specializations may not derive from <tt>integral_constant</tt>, and the 16148places where <tt>is_bind_expression</tt> and <tt>is_placeholder</tt> are 16149used intentionally do not require such derivation. 16150</p> 16151<p> 16152The long-term approach here is to switch to 16153<tt>BindExpression<E></tt> and <tt>Placeholder<P></tt> 16154explicit concepts, of course, but until that happens, I say leave them 16155alone. 16156</p> 16157</blockquote> 16158 16159<p><i>[ 161602009-10 post-Santa Cruz: 16161]</i></p> 16162 16163 16164<blockquote> 16165Move to Tentatively Ready. We are comfortable with requiring user specializations 16166to derive from <tt>integral_constant</tt>. 16167</blockquote> 16168 16169 16170 16171<p><b>Proposed resolution:</b></p> 16172<ol> 16173<li> 16174<p> 16175In 20.7.11.1.1 [func.bind.isbind] change as indicated: 16176</p> 16177<blockquote><pre>namespace std { 16178 template<class T> struct is_bind_expression <ins>: integral_constant<bool, <i>see below</i>> { };</ins><del>{ 16179 static const bool value = <i>see below</i>; 16180 };</del> 16181} 16182</pre></blockquote> 16183</li> 16184<li> 16185<p> 16186In 20.7.11.1.1 [func.bind.isbind]/2 change as indicated: 16187</p> 16188<blockquote><pre><del>static const bool value;</del> 16189</pre> 16190<blockquote> 16191-2- <del><tt>true</tt> if <tt>T</tt> is a type returned from <tt>bind</tt>, <tt>false</tt> otherwise.</del> 16192 <ins>If <tt>T</tt> is a type returned from <tt>bind</tt>, <tt>is_bind_expression<T></tt> shall 16193be publicly derived from 16194 <tt>integral_constant<bool, true></tt>, otherwise it shall be 16195publicly derived from 16196 <tt>integral_constant<bool, false></tt>.</ins> 16197</blockquote> 16198</blockquote> 16199</li> 16200<li> 16201<p> 16202In 20.7.11.1.2 [func.bind.isplace] change as indicated: 16203</p> 16204<blockquote><pre>namespace std { 16205 template<class T> struct is_placeholder <ins>: integral_constant<int, <i>see below</i>> { };</ins><del>{ 16206 static const int value = <i>see below</i>; 16207 };</del> 16208} 16209</pre></blockquote> 16210</li> 16211<li> 16212<p> 16213In 20.7.11.1.2 [func.bind.isplace]/2 change as indicated: 16214</p> 16215<blockquote><pre><del>static const int value;</del> 16216</pre> 16217<blockquote> 16218-2- <del>value is <tt>J</tt> if <tt>T</tt> is the type of <tt>std::placeholders::_J</tt>, 0 otherwise.</del> 16219 <ins>If <tt>T</tt> is the type of <tt>std::placeholders::_J</tt>, <tt>is_placeholder<T></tt> 16220shall be publicly 16221 derived from <tt>integral_constant<int, J></tt> otherwise it shall 16222be publicly derived 16223 from <tt>integral_constant<int, 0></tt>.</ins> 16224</blockquote> 16225</blockquote> 16226</li> 16227</ol> 16228 16229 16230 16231 16232 16233<hr> 16234<h3><a name="1076"></a>1076. unary/binary_negate need constraining and move support</h3> 16235<p><b>Section:</b> 20.7.10 [negators] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 16236 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-03-20 <b>Last modified:</b> 2009-10-26</p> 16237<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 16238<p><b>Discussion:</b></p> 16239<p> 16240The class templates <tt>unary/binary_negate</tt> need constraining and move support. 16241</p> 16242<p> 16243Ideally these classes would be deprecated, allowing <tt>unary/binary_function</tt> to 16244also be deprecated. However, until a generic negate adaptor is introduced 16245that can negate any <tt>Callable</tt> type, they must be supported so should be 16246constrained. Likewise, they should be movable, and support adopting a 16247move-only predicate type. 16248</p> 16249<p> 16250In order to preserve ABI compatibility, new rvalue overloads are supplied in 16251preference to changing the existing pass-by-const-ref to pass-by-value. 16252</p> 16253<p> 16254Do not consider the issue of forwarding mutable lvalues at this point, 16255although remain open to another issue on the topic. 16256</p> 16257 16258<p><i>[ 162592009-05-01 Daniel adds: 16260]</i></p> 16261 16262<blockquote> 16263<p> 16264IMO the currently proposed resolution needs some updates 16265because it is ill-formed at several places: 16266</p> 16267 16268<ol> 16269<li> 16270<p> 16271In concept AdaptableUnaryFunction change 16272</p> 16273<blockquote><pre>typename X::result_type; 16274typename X::argument_type; 16275</pre></blockquote> 16276<p> 16277to 16278</p> 16279<blockquote><pre>Returnable result_type = typename X::result_type; 16280typename argument_type = typename X::argument_type; 16281</pre></blockquote> 16282<p> 16283[The replacement "Returnable result_type" instead of "typename 16284result_type" is non-editorial, but maybe you prefer that as well] 16285</p> 16286</li> 16287<li> 16288<p> 16289In concept AdaptableBinaryFunction change 16290</p> 16291<blockquote><pre>typename X::result_type; 16292typename X::first_argument_type; 16293typename X::second_argument_type; 16294</pre></blockquote> 16295<p> 16296to 16297</p> 16298<blockquote><pre>Returnable result_type = typename X::result_type; 16299typename first_argument_type = typename X::first_argument_type; 16300typename second_argument_type = typename X::second_argument_type; 16301</pre></blockquote> 16302<p> 16303[The replacement "Returnable result_type" instead of "typename 16304result_type" is non-editorial, but maybe you prefer that as well.] 16305</p> 16306</li> 16307 16308<li> 16309<p> 16310In class unary/binary_function 16311</p> 16312<ol type="a"> 16313<li> 16314I suggest to change "ReturnType" to "Returnable" in both cases. 16315</li> 16316<li> 16317I think you want to replace the remaining occurrences of "Predicate" by "P" 16318(in both classes in copy/move from a predicate) 16319</li> 16320</ol> 16321</li> 16322<li> 16323<p> 16324I think you need to change the proposed signatures of not1 and not2, because 16325they would still remain unconstrained: To make them constrained at least a 16326single requirement needs to be added to enable requirement implication. This 16327could be done via a dummy ("requires True<true>") or just explicit as follows: 16328</p> 16329<ol type="a"> 16330<li> 16331<blockquote><pre>template <AdaptableUnaryFunction P> 16332requires Predicate< P, P::argument_type> 16333unary_negate<P> not1(const P&& pred); 16334template <AdaptableUnaryFunction P> 16335requires Predicate< P, P::argument_type > 16336unary_negate<P> not1(P&& pred); 16337</pre> 16338<blockquote> 16339-3- Returns: unary_negate<P>(pred). 16340</blockquote> 16341</blockquote> 16342<p> 16343[Don't we want a move call for the second overload as in 16344</p> 16345<blockquote><pre>unary_negate<P>(std::move(pred)) 16346</pre></blockquote> 16347<p> 16348in the Returns clause ?] 16349</p> 16350</li> 16351<li> 16352<pre>template <AdaptableBinaryFunction P> 16353requires Predicate< P, P::first_argument_type, P::second_argument_type > 16354binary_negate<P> not2(const P& pred); 16355template <AdaptableBinaryFunction P> 16356requires Predicate< P, P::first_argument_type, P::second_argument_type > 16357binary_negate<P> not2(P&& pred); 16358</pre> 16359<p> 16360-5- Returns: binary_negate<P>(pred). 16361</p> 16362<p> 16363[Don't we want a move call for the second overload as in 16364</p> 16365<blockquote><pre>binary_negate<P>(std::move(pred)) 16366</pre></blockquote> 16367<p> 16368in the Returns clause ?] 16369</p> 16370</li> 16371</ol> 16372</li> 16373</ol> 16374</blockquote> 16375 16376<p><i>[ 16377Batavia (2009-05): 16378]</i></p> 16379 16380<blockquote> 16381<p> 16382There is concern that complicating the solution 16383to preserve the ABI seems unnecessary, 16384since we're not in general preserving the ABI. 16385</p> 16386<p> 16387We would prefer a separate paper consolidating all Clause 20 16388issues that are for the purpose of providing constrained versions 16389of the existing facilities. 16390</p> 16391<p> 16392Move to Open. 16393</p> 16394</blockquote> 16395 16396<p><i>[ 163972009-10 post-Santa Cruz: 16398]</i></p> 16399 16400 16401<blockquote> 16402Leave open pending the potential move constructor paper. Note that 16403we consider the "constraining" part NAD Concepts. 16404</blockquote> 16405 16406 16407 16408<p><b>Proposed resolution:</b></p> 16409<p> 16410Add new concepts where appropriate:: 16411</p> 16412 16413<blockquote><pre>auto concept AdaptableUnaryFunction< typename X > { 16414 typename X::result_type; 16415 typename X::argument_type; 16416} 16417 16418auto concept AdaptableBinaryFunction< typename X > { 16419 typename X::result_type; 16420 typename X::first_argument_type; 16421 typename X::second_argument_type; 16422} 16423</pre></blockquote> 16424 16425<p> 16426Revise as follows: 16427</p> 16428 16429<p> 16430Base 20.7.3 [base] (Only change is constrained Result) 16431</p> 16432 16433<blockquote> 16434<p> 16435-1- The following classes are provided to simplify the typedefs of the 16436argument and result types: 16437</p> 16438<pre>namespace std { 16439 template <class Arg, <del>class</del> <ins>ReturnType</ins> Result> 16440 struct unary_function { 16441 typedef Arg argument_type; 16442 typedef Result result_type; 16443 }; 16444 16445 template <class Arg1, class Arg2, <del>class</del> <ins>ReturnType</ins> Result> 16446 struct binary_function { 16447 typedef Arg1 first_argument_type; 16448 typedef Arg2 second_argument_type; 16449 typedef Result result_type; 16450 }; 16451} 16452</pre></blockquote> 16453 16454<p> 16455Negators 20.7.10 [negators]: 16456</p> 16457 16458<blockquote> 16459<p> 16460-1- Negators <tt>not1</tt> and <tt>not2</tt> take a unary and a binary predicate, 16461respectively, and return their complements (5.3.1). 16462</p> 16463 16464<pre>template <<del>class</del> <ins>AdaptableUnaryFunction</ins> P<del>redicate</del>> 16465 <ins>requires Predicate< P, P::argument_type ></ins> 16466 class unary_negate 16467 : public unary_function<<del>typename</del> P<del>redicate</del>::argument_type,bool> { 16468 public: 16469 <ins>unary_negate(const unary_negate & ) = default;</ins> 16470 <ins>unary_negate(unary_negate && );</ins> 16471 16472 <ins>requires CopyConstructible< P ></ins> 16473 explicit unary_negate(const Predicate& pred); 16474 <ins>requires MoveConstructible< P > 16475 explicit unary_negate(Predicate && pred);</ins> 16476 16477 bool operator()(const <del>typename</del> P<del>redicate</del>::argument_type& x) const; 16478 }; 16479</pre> 16480<blockquote> 16481-2 <tt>operator()</tt> returns <tt>!pred(x)</tt>. 16482</blockquote> 16483 16484<pre>template <class Predicate> 16485 unary_negate<Predicate> not1(const Predicate&amp; pred); 16486<ins>template <class Predicate> 16487 unary_negate<Predicate> not1(Predicate&& pred);</ins> 16488</pre> 16489<blockquote> 16490-3- <i>Returns:</i> <tt>unary_negate<Predicate>(pred)</tt>. 16491</blockquote> 16492 16493<pre>template <<del>class</del> <ins>AdaptableBinaryFunction</ins> P<del>redicate</del> > 16494 <ins>requires Predicate< P, P::first_argument_type, P::second_argument_type ></ins> 16495 class binary_negate 16496 : public binary_function<<del>typename</del> P<del>redicate</del>::first_argument_type, 16497 <del>typename</del> P<del>redicate</del>::second_argument_type, bool> { 16498 public: 16499 <ins>biary_negate(const binary_negate & ) = default;</ins> 16500 <ins>binary_negate(binary_negate && );</ins> 16501 16502 <ins>requires CopyConstructible< P ></ins> 16503 explicit binary_negate(const Predicate& pred); 16504 <ins>requires MoveConstructible< P > 16505 explicit binary_negate(const Predicate& pred);</ins> 16506 16507 bool operator()(const <del>typename</del> P<del>redicate</del>::first_argument_type& x, 16508 const <del>typename</del> P<del>redicate</del>::second_argument_type& y) const; 16509 }; 16510</pre> 16511<blockquote> 16512-4- <tt>operator()</tt> returns <tt>!pred(x,y)</tt>. 16513</blockquote> 16514 16515<pre>template <class Predicate> 16516 binary_negate<Predicate> not2(const Predicate& pred); 16517<ins>template <class Predicate> 16518 binary_negate<Predicate> not2(Predicate&& pred);</ins> 16519</pre> 16520 16521<blockquote> 16522-5- <i>Returns:</i> <tt>binary_negate<Predicate>(pred)</tt>. 16523</blockquote> 16524</blockquote> 16525 16526 16527 16528 16529 16530 16531<hr> 16532<h3><a name="1079"></a>1079. UK-265: <code>RandomAccessIterator</code>'s <code>operator-</code> has nonsensical effects clause</h3> 16533<p><b>Section:</b> 24.2.5 [random.access.iterators] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 16534 <b>Submitter:</b> Doug Gregor <b>Opened:</b> 2009-03-20 <b>Last modified:</b> 2009-10-23</p> 16535<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#random.access.iterators">issues</a> in [random.access.iterators].</p> 16536<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 16537<p><b>Discussion:</b></p> 16538<p><b>Addresses UK 265</b></p> 16539 16540<p>UK-265:</p> 16541<p> 16542This effects clause is nonesense. It looks more like an axiom stating 16543equivalence, and certainly an effects clause cannot change the state of 16544two arguments passed by const reference 16545</p> 16546 16547<p><i>[ 165482009-09-18 Alisdair adds: 16549]</i></p> 16550 16551 16552<blockquote> 16553<p> 16554For random access iterators, the definitions of <tt>(b-a)</tt> and 16555<tt>(a<b)</tt> are circular: 16556</p> 16557 16558<p> 16559From table Table 104 -- Random access iterator requirements: 16560</p> 16561 16562<blockquote><pre>b - a :==> (a < b) ? distance(a,b) : -distance(b,a) 16563 16564a < b :==> b - a > 0 16565</pre></blockquote> 16566</blockquote> 16567 16568<p><i>[ 165692009-10 Santa Cruz: 16570]</i></p> 16571 16572 16573<blockquote> 16574Moved to Ready. 16575</blockquote> 16576 16577 16578 16579<p><b>Proposed resolution:</b></p> 16580 16581<p>Modify 24.2.5 [random.access.iterators]p7-9 as follows:</p> 16582 16583<blockquote><pre>difference_type operator-(const X& a, const X& b); 16584</pre> 16585<ol start="7"> 16586 <li><i>Precondition</i>: there exists a value <code>n</code> of 16587 <code>difference_type</code> such that <code>a == b + n</code>.</li> 16588 <li><del><i>Effects</i>: <code>b == a + (b - a)</code></del></li> 16589 <li><i>Returns</i>: <del><code>(a < b) ? distance(a,b) : 16590 -distance(b,a)</code></del><ins><code>n</code></ins></li> 16591</ol> 16592</blockquote> 16593 16594 16595 16596 16597 16598<hr> 16599<h3><a name="1089"></a>1089. Response to JP 76</h3> 16600<p><b>Section:</b> 30 [thread] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 16601 <b>Submitter:</b> Howard Hinnant <b>Opened:</b> 2009-03-22 <b>Last modified:</b> 2009-10-23</p> 16602<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#thread">issues</a> in [thread].</p> 16603<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 16604<p><b>Discussion:</b></p> 16605<p><b>Addresses JP 76</b></p> 16606 16607<p> 16608A description for "Throws: Nothing." are not unified. 16609</p> 16610 16611<p> 16612At the part without throw, "Throws: Nothing." should be described. 16613</p> 16614 16615<p> 16616Add "Throws: Nothing." to the following. 16617</p> 16618 16619<ul> 16620<li> 1662130.3.1.6 [thread.thread.static] p1 16622</li> 16623<li> 1662430.4.3.1 [thread.lock.guard] p4 16625</li> 16626<li> 1662730.4.3.2.1 [thread.lock.unique.cons] p6 16628</li> 16629<li> 1663030.5.1 [thread.condition.condvar] p7 and p8 16631</li> 16632<li> 1663330.5.2 [thread.condition.condvarany] p6, p7, p19, p21 and p25 16634</li> 16635</ul> 16636 16637<p><i>[ 16638Summit: 16639]</i></p> 16640 16641<blockquote> 16642Pass on to editor. 16643</blockquote> 16644 16645<p><i>[ 16646Post Summit: Editor declares this non-editorial. 16647]</i></p> 16648 16649 16650<p><i>[ 166512009-08-01 Howard provided wording: 16652]</i></p> 16653 16654 16655<blockquote> 16656 16657<p> 16658The definition of "<i>Throws:</i> Nothing." that I added is probably going to 16659be controversial, but I beg you to consider it seriously. 16660</p> 16661 16662<blockquote> 16663<p> 16664In C++ there are three "flow control" options for a function: 16665</p> 16666 16667<ol> 16668<li> 16669It can return, either with a value, or with <tt>void</tt>. 16670</li> 16671<li> 16672It can call a function which never returns, such as <tt>std::exit</tt> or 16673<tt>std::terminate</tt>. 16674</li> 16675<li> 16676It can throw an exception. 16677</li> 16678</ol> 16679 16680The above list can be abbreviated with: 16681 16682<ol> 16683<li><b>R</b>eturns.</li> 16684<li><b>E</b>nds program.</li> 16685<li><b>T</b>hrows exception.</li> 16686</ol> 16687 16688<p> 16689In general a function can have the behavior of any of these 3, or any combination 16690of any of these three, depending upon run time data. 16691</p> 16692 16693<ol> 16694<li><b>R</b></li> 16695<li><b>E</b></li> 16696<li><b>T</b></li> 16697<li><b>RE</b></li> 16698<li><b>RT</b></li> 16699<li><b>ET</b></li> 16700<li><b>RET</b></li> 16701</ol> 16702 16703<p> 16704A function with no throw spec, and no documentation, is in general a <b>RET</b> 16705function. It may return, it may end the program, or it may throw. When we 16706specify a function with an empty throw spec: 16707</p> 16708 16709<blockquote><pre>void f() throw(); 16710</pre></blockquote> 16711 16712<p> 16713We are saying that <tt>f()</tt> is an <b>RE</b> function: It may return or end 16714the program, but it will not throw. 16715</p> 16716 16717<p> 16718I posit that there are very few places in the library half of the standard 16719where we intend for functions to be able to end the program (call <tt>terminate</tt>). 16720And none of those places where we do say <tt>terminate</tt> could be called, 16721do we currently say "<i>Throws:</i> Nothing.". 16722</p> 16723 16724<p> 16725I believe that if we define "<i>Throws:</i> Nothing." to mean <b>R</b>, 16726we will both clarify many, many places in the standard, <em>and</em> give us a 16727good rationale for choosing between "<i>Throws:</i> Nothing." (<b>R</b>) 16728and <tt>throw()</tt> (<b>RE</b>) in the future. Indeed, this may give us motivation 16729to change several <tt>throw()</tt>s to "<i>Throws:</i> Nothing.". 16730</p> 16731</blockquote> 16732 16733<p> 16734I did not add the following changes as JP 76 requested as I believe we want to 16735allow these functions to throw: 16736</p> 16737 16738<blockquote> 16739<p> 16740Add a paragraph under 30.4.3.1 [thread.lock.guard] p4: 16741</p> 16742 16743<blockquote><pre>explicit lock_guard(mutex_type& m); 16744</pre> 16745 16746<p><ins> 16747<i>Throws:</i> Nothing. 16748</ins></p> 16749</blockquote> 16750 16751<p> 16752Add a paragraph under 30.4.3.2.1 [thread.lock.unique.cons] p6: 16753</p> 16754 16755<blockquote><pre>explicit unique_lock(mutex_type& m); 16756</pre> 16757 16758<p><ins> 16759<i>Throws:</i> Nothing. 16760</ins></p> 16761</blockquote> 16762 16763<p> 16764Add a paragraph under 30.5.2 [thread.condition.condvarany] p19, p21 and p25: 16765</p> 16766 16767<blockquote><pre>template <class Lock, class Rep, class Period> 16768 bool wait_for(Lock& lock, const chrono::duration<Rep, Period>& rel_time); 16769</pre> 16770 16771<p><ins> 16772<i>Throws:</i> Nothing. 16773</ins></p> 16774</blockquote> 16775 16776<blockquote><pre>template <class Lock, class Duration, class Predicate> 16777 bool wait_until(Lock& lock, const chrono::time_point<Clock, Duration>& rel_time, Predicate pred); 16778</pre> 16779 16780<p><ins> 16781<i>Throws:</i> Nothing. 16782</ins></p> 16783</blockquote> 16784 16785<blockquote><pre>template <class Lock, class Rep, class Period, class Predicate> 16786 bool wait_for(Lock& lock, const chrono::duration<Rep, Period>& rel_time, Predicate pred); 16787</pre> 16788 16789<p><ins> 16790<i>Throws:</i> Nothing. 16791</ins></p> 16792</blockquote> 16793 16794</blockquote> 16795 16796</blockquote> 16797 16798<p><i>[ 167992009-10 Santa Cruz: 16800]</i></p> 16801 16802 16803<blockquote> 16804Defer pending further developments with exception restriction annotations. 16805</blockquote> 16806 16807 16808 16809<p><b>Proposed resolution:</b></p> 16810<p> 16811Add a paragraph after 17.5.1.4 [structure.specifications] p4: 16812</p> 16813 16814<blockquote> 16815<p> 16816-3- Descriptions of function semantics contain the following elements 16817(as appropriate):<sup>158</sup> 16818</p> 16819<ul> 16820<li>...</li> 16821<li> 16822<i>Throws:</i> any exceptions thrown by the function, and the conditions 16823that would cause the exception 16824</li> 16825<li>...</li> 16826</ul> 16827 16828<p> 16829-4- For non-reserved replacement and handler functions, ... 16830</p> 16831 16832<p><ins> 16833A "<i>Throws:</i> Nothing." element indicates that the function shall 16834return ordinarily, and not exit via an exception. This element also 16835indicates that the function <em>shall</em> return. [<i>Note:</i> This 16836differs from an empty throw specification which may cause a function to 16837call <tt>unexpected</tt> and subsequently <tt>terminate</tt>. — 16838<i>end note</i>] 16839</ins></p> 16840</blockquote> 16841 16842<p> 16843Add a paragraph under 30.3.1.6 [thread.thread.static] p1: 16844</p> 16845 16846<blockquote><pre>unsigned hardware_concurrency(); 16847</pre> 16848 16849<p> 16850-1- <i>Returns:</i> ... 16851</p> 16852 16853<p><ins> 16854<i>Throws:</i> Nothing. 16855</ins></p> 16856</blockquote> 16857 16858<p> 16859Add a paragraph under 30.5.1 [thread.condition.condvar] p7 and p8: 16860</p> 16861 16862<blockquote> 16863<p> 16864<i>[Informational, not to be incluced in the WP: The POSIX spec allows only:</i> 16865</p> 16866<dl> 16867<dt><i>[EINVAL]</i></dt> 16868<dd><i>The value <tt>cond</tt> does not refer to an initialized condition variable. — end informational]</i></dd> 16869</dl> 16870 16871<pre>void notify_one(); 16872</pre> 16873 16874<p> 16875-7- <i>Effects:</i> ... 16876</p> 16877 16878<p><ins> 16879<i>Throws:</i> Nothing. 16880</ins></p> 16881</blockquote> 16882 16883<blockquote><pre>void notify_all(); 16884</pre> 16885 16886<p> 16887-8- <i>Effects:</i> ... 16888</p> 16889 16890<p><ins> 16891<i>Throws:</i> Nothing. 16892</ins></p> 16893</blockquote> 16894 16895 16896<p> 16897Add a paragraph under 30.5.2 [thread.condition.condvarany] p6 and p7: 16898</p> 16899 16900<blockquote> 16901<pre>void notify_one(); 16902</pre> 16903 16904<p> 16905-6- <i>Effects:</i> ... 16906</p> 16907 16908<p><ins> 16909<i>Throws:</i> Nothing. 16910</ins></p> 16911</blockquote> 16912 16913<blockquote><pre>void notify_all(); 16914</pre> 16915 16916<p> 16917-7- <i>Effects:</i> ... 16918</p> 16919 16920<p><ins> 16921<i>Throws:</i> Nothing. 16922</ins></p> 16923</blockquote> 16924 16925 16926 16927 16928 16929 16930 16931<hr> 16932<h3><a name="1090"></a>1090. Missing description of <tt>packaged_task</tt> member <tt>swap</tt>, missing non-member <tt>swap</tt></h3> 16933<p><b>Section:</b> 30.6.10 [futures.task] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Tentatively Ready</a> 16934 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2009-03-22 <b>Last modified:</b> 2009-10-26</p> 16935<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20Ready">Tentatively Ready</a> status.</p> 16936<p><b>Discussion:</b></p> 16937<p> 16938Class template <tt>packaged_task</tt> in 30.6.10 [futures.task] shows a member <tt>swap</tt> 16939declaration, but misses to 16940document it's effects (No prototype provided). Further on this class 16941misses to provide a non-member 16942swap. 16943</p> 16944 16945<p><i>[ 16946Batavia (2009-05): 16947]</i></p> 16948 16949<blockquote> 16950<p> 16951Alisdair notes that paragraph 2 of the proposed resolution has already been 16952applied in the current Working Draft. 16953</p> 16954<p> 16955We note a pending <tt>future</tt>-related paper by Detlef; 16956we would like to wait for this paper before proceeding. 16957</p> 16958<p> 16959Move to Open. 16960</p> 16961</blockquote> 16962 16963<p><i>[ 169642009-05-24 Daniel removed part 2 of the proposed resolution. 16965]</i></p> 16966 16967 16968<p><i>[ 169692009-10 post-Santa Cruz: 16970]</i></p> 16971 16972 16973<blockquote> 16974Move to Tentatively Ready, removing bullet 3 from the proposed 16975resolution but keeping the other two bullets. 16976</blockquote> 16977 16978 16979 16980<p><b>Proposed resolution:</b></p> 16981<ol> 16982<li> 16983<p> 16984In 30.6.10 [futures.task], immediately after the definition of class 16985template packaged_task add: 16986</p> 16987<blockquote><pre><ins> 16988template<class R, class... Argtypes> 16989void swap(packaged_task<R(ArgTypes...)>&, packaged_task<R(ArgTypes...)>&); 16990</ins> 16991</pre></blockquote> 16992</li> 16993</ol> 16994 16995<ol start="4"> 16996 16997<li> 16998<p> 16999At the end of 30.6.10 [futures.task] (after p. 20), add add the following 17000prototype description: 17001</p> 17002 17003<blockquote><pre><ins> 17004template<class R, class... Argtypes> 17005void swap(packaged_task<R(ArgTypes...)>& x, packaged_task<R(ArgTypes...)>& y); 17006</ins></pre> 17007<blockquote> 17008<p><ins> 17009<i>Effects:</i> <tt>x.swap(y)</tt> 17010</ins></p> 17011<p><ins> 17012<i>Throws:</i> Nothing. 17013</ins></p> 17014</blockquote> 17015</blockquote> 17016</li> 17017</ol> 17018 17019 17020 17021 17022 17023<hr> 17024<h3><a name="1093"></a>1093. Multiple definitions for random_shuffle algorithm</h3> 17025<p><b>Section:</b> 25.3.12 [alg.random.shuffle] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 17026 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-03-22 <b>Last modified:</b> 2009-10-26</p> 17027<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#alg.random.shuffle">issues</a> in [alg.random.shuffle].</p> 17028<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 17029<p><b>Discussion:</b></p> 17030 17031<p> 17032There are a couple of issues with the declaration of the <tt>random_shuffle</tt> 17033algorithm accepting a random number engine. 17034</p> 17035 17036<ol type="i"> 17037<li> 17038The Iterators must be shuffle iterators, yet this requirement is missing. 17039</li> 17040<li> 17041The <tt>RandomNumberEngine</tt> concept is now provided by the random number 17042library 17043(<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2836.pdf">n2836</a>) 17044and the placeholder should be removed. 17045</li> 17046</ol> 17047 17048<p><i>[ 170492009-05-02 Daniel adds: 17050]</i></p> 17051 17052 17053<blockquote> 17054<p> 17055this issue completes adding necessary requirement to the 17056third new <tt>random_shuffle</tt> overload. The current suggestion is: 17057</p> 17058 17059<blockquote><pre>template<RandomAccessIterator Iter, UniformRandomNumberGenerator Rand> 17060requires ShuffleIterator<Iter> 17061void random_shuffle(Iter first, Iter last, Rand&& g); 17062</pre></blockquote> 17063 17064<p> 17065IMO this is still insufficient and I suggest to add the requirement 17066</p> 17067<blockquote><pre>Convertible<Rand::result_type, Iter::difference_type> 17068</pre></blockquote> 17069<p> 17070to the list (as the two other overloads already have). 17071</p> 17072 17073<p> 17074Rationale: 17075</p> 17076 17077<blockquote> 17078<p> 17079Its true that this third overload is somewhat different from the remaining 17080two. Nevertheless we know from <tt>UniformRandomNumberGenerator</tt>, that 17081it's <tt>result_type</tt> is an integral type and that it satisfies 17082<tt>UnsignedIntegralLike<result_type></tt>. 17083</p> 17084<p> 17085To realize it's designated task, the algorithm has to invoke the 17086<tt>Callable</tt> aspect of <tt>g</tt> and needs to perform some algebra involving 17087it's <tt>min()/max()</tt> limits to compute another index value that 17088at this point is converted into <tt>Iter::difference_type</tt>. This is so, 17089because 24.2.5 [random.access.iterators] uses this type as argument 17090of it's algebraic operators. Alternatively consider the equivalent 17091iterator algorithms in 24.4.4 [iterator.operations] with the same result. 17092</p> 17093<p> 17094This argument leads us to the conclusion that we also need 17095<tt>Convertible<Rand::result_type, Iter::difference_type></tt> here. 17096</p> 17097</blockquote> 17098 17099</blockquote> 17100 17101<p><i>[ 17102Batavia (2009-05): 17103]</i></p> 17104 17105<blockquote> 17106<p> 17107Alisdair notes that point (ii) has already been addressed. 17108</p> 17109<p> 17110We agree with the proposed resolution to point (i) 17111with Daniel's added requirement. 17112</p> 17113<p> 17114Move to Review. 17115</p> 17116</blockquote> 17117 17118<p><i>[ 171192009-06-05 Daniel updated proposed wording as recommended in Batavia. 17120]</i></p> 17121 17122 17123<p><i>[ 171242009-07-28 Alisdair adds: 17125]</i></p> 17126 17127 17128<blockquote> 17129Revert to Open, with a note there is consensus on direction but the 17130wording needs updating to reflect removal of concepts. 17131</blockquote> 17132 17133<p><i>[ 171342009-10 post-Santa Cruz: 17135]</i></p> 17136 17137 17138<blockquote> 17139Leave Open, Walter to work on it. 17140</blockquote> 17141 17142 17143 17144<p><b>Proposed resolution:</b></p> 17145<p> 17146Change in [algorithms.syn] and 25.3.12 [alg.random.shuffle]: 17147</p> 17148 17149<blockquote><pre><del>concept UniformRandomNumberGenerator<typename Rand> { }</del> 17150template<RandomAccessIterator Iter, UniformRandomNumberGenerator Rand> 17151 <ins>requires ShuffleIterator<Iter> && 17152 Convertible<Rand::result_type, Iter::difference_type></ins> 17153 void random_shuffle(Iter first, Iter last, Rand&& g); 17154</pre></blockquote> 17155 17156 17157 17158 17159 17160 17161<hr> 17162<h3><a name="1094"></a>1094. Response to JP 65 and JP 66</h3> 17163<p><b>Section:</b> 27.5.4.3 [iostate.flags] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 17164 <b>Submitter:</b> P.J. Plauger <b>Opened:</b> 2009-03-24 <b>Last modified:</b> 2009-10-20</p> 17165<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#iostate.flags">issues</a> in [iostate.flags].</p> 17166<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 17167<p><b>Discussion:</b></p> 17168<p><b>Addresses JP 65 and JP 66</b></p> 17169 17170<p> 17171Switch from "unspecified-bool-type" to "explicit operator bool() const". 17172</p> 17173 17174<p> 17175Replace <tt>operator unspecified-bool-type() const;</tt>" with <tt>explicit operator bool() const;</tt> 17176</p> 17177 17178<p><i>[ 17179Batavia (2009-05): 17180]</i></p> 17181 17182<blockquote> 17183We agree with the proposed resolution. 17184Move to Review. 17185</blockquote> 17186 17187<p><i>[ 171882009 Santa Cruz: 17189]</i></p> 17190 17191 17192<blockquote> 17193Moved to Ready. 17194</blockquote> 17195 17196 17197 17198<p><b>Proposed resolution:</b></p> 17199<p> 17200Change the synopis in 27.5.4 [ios]: 17201</p> 17202 17203<blockquote><pre><ins>explicit</ins> operator <del><i>unspecified-bool-type</i></del> <ins>bool</ins>() const; 17204</pre></blockquote> 17205 17206<p> 17207Change 27.5.4.3 [iostate.flags]: 17208</p> 17209 17210<blockquote><pre><ins>explicit</ins> operator <del><i>unspecified-bool-type</i></del> <ins>bool</ins>() const; 17211</pre> 17212 17213<blockquote> 17214<p> 17215-1- <i>Returns:</i> <ins><tt>!fail()</tt></ins> <del>If <tt>fail()</tt> then a value that will evaluate 17216false in a boolean context; otherwise a value that will evaluate true in 17217a boolean context. The value type returned shall not be convertible to 17218int.</del> 17219</p> 17220<p> 17221<del>[<i>Note:</i> This conversion can be used in contexts where a bool is expected 17222(e.g., an <tt>if</tt> condition); however, implicit conversions (e.g., 17223to <tt>int</tt>) that can occur with <tt>bool</tt> are not allowed, 17224eliminating some sources of user error. One possible implementation 17225choice for this type is pointer-to-member. <i>-- end note</i>]</del> 17226</p> 17227</blockquote> 17228</blockquote> 17229 17230 17231 17232 17233 17234 17235 17236<hr> 17237<h3><a name="1095"></a>1095. <i>Shared objects and the library</i> wording unclear</h3> 17238<p><b>Section:</b> 17.6.3.10 [res.on.objects] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 17239 <b>Submitter:</b> Beman Dawes <b>Opened:</b> 2009-03-27 <b>Last modified:</b> 2009-10-21</p> 17240<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 17241<p><b>Discussion:</b></p> 17242<p> 17243<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2775.htm">N2775</a>, 17244<i>Small library thread-safety revisions</i>, among other changes, removed a note from 1724517.6.3.10 [res.on.objects] that read: 17246</p> 17247 17248<blockquote> 17249[<i>Note:</i> This prohibition against concurrent non-const access means that 17250modifying an object of a standard library type shared between threads 17251without using a locking mechanism may result in a data race. <i>--end note</i>.] 17252</blockquote> 17253 17254<p> 17255That resulted in wording which is technically correct but can only be 17256understood by reading the lengthy and complex 17.6.4.8 [res.on.data.races] 17257Data race avoidance. This has the effect of making 1725817.6.3.10 [res.on.objects] unclear, and has already resulted in a query 17259to the LWG reflector. See c++std-lib-23194. 17260</p> 17261 17262<p><i>[ 17263Batavia (2009-05): 17264]</i></p> 17265 17266<blockquote> 17267<p> 17268The proposed wording seems to need a bit of tweaking 17269("really bad idea" isn't quite up to standardese). 17270We would like feedback 17271as to whether the original Note's removal was intentional. 17272</p> 17273<p> 17274Change the phrase "is a really bad idea" 17275to "risks undefined behavior" and 17276move to Review status. 17277</p> 17278</blockquote> 17279 17280<p><i>[ 172812009-10 Santa Cruz: 17282]</i></p> 17283 17284 17285<blockquote> 17286Note: Change to read: "Modifying...", Delete 'thus', move to Ready 17287</blockquote> 17288 17289 17290 17291<p><b>Proposed resolution:</b></p> 17292<p> 17293Change 17.6.3.10 [res.on.objects] as indicated: 17294</p> 17295 17296<blockquote> 17297<p> 17298The behavior of a program is undefined if calls to standard library 17299functions from different threads may introduce a data race. The 17300conditions under which this may occur are specified in 17.6.4.7. 17301</p> 17302<p><ins> 17303[<i>Note:</i> Modifying an object of a standard library type shared between 17304threads risks undefined behavior unless objects of the type are explicitly 17305specified as being sharable without data races or the user supplies a 17306locking mechanism. <i>--end note</i>] 17307</ins></p> 17308</blockquote> 17309 17310 17311 17312 17313 17314<hr> 17315<h3><a name="1097"></a>1097. #define __STDCPP_THREADS</h3> 17316<p><b>Section:</b> 18.2 [support.types] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 17317 <b>Submitter:</b> Jens Maurer <b>Opened:</b> 2009-04-03 <b>Last modified:</b> 2009-10-21</p> 17318<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#support.types">issues</a> in [support.types].</p> 17319<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 17320<p><b>Discussion:</b></p> 17321<p><b>Addresses DE 18</b></p> 17322 17323<p> 17324Freestanding implementations do not (necessarily) have 17325 support for multiple threads (see 1.10 [intro.multithread]). 17326 Applications and libraries may want to optimize for the 17327 absence of threads. I therefore propose a preprocessor 17328 macro to indicate whether multiple threads can occur. 17329</p> 17330 17331<p> 17332There is ample prior implementation experience for this 17333 feature with various spellings of the macro name. For 17334 example, gcc implicitly defines <tt>_REENTRANT</tt> 17335 if multi-threading support is selected on the compiler 17336 command-line. 17337</p> 17338 17339<p> 17340While this is submitted as a library issue, it may be more 17341 appropriate to add the macro in 16.8 cpp.predefined in the 17342 core language. 17343</p> 17344 17345<p> 17346See also 17347<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2693.html">N2693</a>. 17348</p> 17349 17350<p><i>[ 17351Batavia (2009-05): 17352]</i></p> 17353 17354<blockquote> 17355<p> 17356We agree with the issue, and believe it is properly a library issue. 17357</p> 17358<p> 17359We prefer that the macro be conditionally defined 17360as part of the <tt><thread></tt> header. 17361</p> 17362<p> 17363Move to Review. 17364</p> 17365</blockquote> 17366 17367<p><i>[ 173682009-10 Santa Cruz: 17369]</i></p> 17370 17371 17372<blockquote> 17373Move to Ready. 17374</blockquote> 17375 17376 17377 17378<p><b>Proposed resolution:</b></p> 17379<p> 17380Insert a new subsection before 18.2 [support.types], entitled 17381"Feature Macros" (support.macros): 17382</p> 17383<blockquote> 17384<p> 17385The standard library defines the following macros; no explicit 17386prior inclusion of any header file is necessary. 17387</p> 17388<blockquote> 17389<dl> 17390<dt><tt>__STDCPP_THREADS</tt></dt> 17391<dd> 17392The macro <tt>__STDCPP_THREADS</tt> shall be defined if and only if a 17393 program can have more than one thread of execution (1.10 [intro.multithread]). 17394If the macro is defined, it shall have the same 17395 value as the predefined macro <tt>__cplusplus</tt> (16.8 [cpp.predefined]). 17396</dd> 17397</dl> 17398</blockquote> 17399</blockquote> 17400 17401 17402 17403 17404 17405 17406<hr> 17407<h3><a name="1098"></a>1098. definition of get_pointer_safety()</h3> 17408<p><b>Section:</b> 20.8.15.6 [util.dynamic.safety] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 17409 <b>Submitter:</b> Jens Maurer <b>Opened:</b> 2009-04-03 <b>Last modified:</b> 2009-10-23</p> 17410<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#util.dynamic.safety">issues</a> in [util.dynamic.safety].</p> 17411<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 17412<p><b>Discussion:</b></p> 17413<p><b>Addresses DE 18</b></p> 17414 17415<p> 17416 In 20.8.15.6 [util.dynamic.safety], <tt>get_pointer_safety()</tt> purports 17417to define behavior for 17418 non-safely derived pointers (3.7.4.3 [basic.stc.dynamic.safety]). However, 17419 the cited core-language section in paragraph 4 specifies undefined behavior 17420 for the use of such pointer values. This seems an unfortunate near-contradiction. 17421 I suggest to specify the term <i>relaxed pointer safety</i> in 17422 the core language section and refer to it from the library description. 17423 This issue deals with the library part, the corresponding core issue (c++std-core-13940) 17424 deals with the core modifications. 17425</p> 17426 17427<p> 17428See also 17429<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2693.html">N2693</a>. 17430</p> 17431 17432<p><i>[ 17433Batavia (2009-05): 17434]</i></p> 17435 17436<blockquote> 17437<p> 17438We recommend if this issue is to be moved, 17439the issue be moved concurrently with the cited Core issue. 17440</p> 17441<p> 17442We agree with the intent of the proposed resolution. 17443We would like input from garbage collection specialists. 17444</p> 17445<p> 17446Move to Open. 17447</p> 17448</blockquote> 17449 17450<p><i>[ 174512009-10 Santa Cruz: 17452]</i></p> 17453 17454 17455<blockquote> 17456The core issue is 853 and is in Ready status. 17457</blockquote> 17458 17459 17460 17461<p><b>Proposed resolution:</b></p> 17462<p> 17463In 20.8.15.6 [util.dynamic.safety] p16, replace the description of 17464<tt>get_pointer_safety()</tt> with: 17465</p> 17466 17467<blockquote> 17468<p> 17469<tt>pointer_safety get_pointer_safety();</tt> 17470</p> 17471<blockquote> 17472<p> 17473<del><i>Returns:</i> an enumeration value indicating the implementation's treatment 17474of pointers that are not safely derived (3.7.4.3). Returns 17475<tt>pointer_safety::relaxed</tt> if pointers that are not safely derived will be 17476treated the same as pointers that are safely derived for the duration of 17477the program. Returns <tt>pointer_safety::preferred</tt> if pointers that are not 17478safely derived will be treated the same as pointers that are safely 17479derived for the duration of the program but allows the implementation to 17480hint that it could be desirable to avoid dereferencing pointers that are 17481not safely derived as described. [<i>Example:</i> <tt>pointer_safety::preferred</tt> 17482might be returned to detect if a leak detector is running to avoid 17483spurious leak reports. -- <i>end note</i>] Returns <tt>pointer_safety::strict</tt> if 17484pointers that are not safely derived might be treated differently than 17485pointers that are safely derived.</del> 17486</p> 17487<p><ins> 17488<i>Returns:</i> Returns <tt>pointer_safety::strict</tt> if the implementation has 17489 strict pointer safety (3.7.4.3 [basic.stc.dynamic.safety]). It is 17490 implementation-defined whether <tt>get_pointer_safety</tt> returns 17491 <tt>pointer_safety::relaxed</tt> or <tt>pointer_safety::preferred</tt> if the 17492 implementation has relaxed pointer safety 17493 (3.7.4.3 [basic.stc.dynamic.safety]).<sup>Footnote</sup> 17494</ins></p> 17495 17496<p><ins> 17497<i>Throws:</i> nothing 17498</ins></p> 17499 17500<p><ins> 17501Footnote) <tt>pointer_safety::preferred</tt> might be returned to indicate to the 17502 program that a leak detector is running so that the program can avoid 17503 spurious leak reports. 17504</ins> 17505</p> 17506 17507</blockquote> 17508</blockquote> 17509 17510 17511 17512 17513 17514<hr> 17515<h3><a name="1099"></a>1099. Various issues</h3> 17516<p><b>Section:</b> 17 [library] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD">Tentatively NAD</a> 17517 <b>Submitter:</b> David Abrahams <b>Opened:</b> 2009-03-21 <b>Last modified:</b> 2009-10-26</p> 17518<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#library">active issues</a> in [library].</p> 17519<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#library">issues</a> in [library].</p> 17520<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20NAD">Tentatively NAD</a> status.</p> 17521<p><b>Discussion:</b></p> 17522<p> 17523Notes 17524</p> 17525<blockquote> 17526<p> 17527[2009-03-21 Sat] p. 535 at the top we need MoveConstructible V1, 17528MoveConstructible V2 (where V1,V2 are defined on 539). Also make_tuple 17529on 550 17530</p> 17531 17532<blockquote> 17533<p> 17534CD-1 reads: 17535</p> 17536 17537<blockquote><pre>template <MoveConstructible T1, MoveConstructible T2> 17538pair<V1, V2> make_pair(T1&&, T2&&); 17539</pre></blockquote> 17540 17541<p> 17542Actually I'm guessing we need something like <tt>MoveConstructible<V1,T1></tt>, 17543i.e. "<tt>V1</tt> can be constructed from an rvalue of type <tt>T1</tt>." 17544</p> 17545 17546<p> 17547Ditto for <tt>make_tuple</tt> 17548</p> 17549</blockquote> 17550 17551<p> 17552[2009-03-21 Sat] p1183 thread ctor, and in general, we need a way to 17553talk about "copiable from generalized rvalue ref argument" for cases 17554where we're going to forward and copy. 17555</p> 17556<blockquote> 17557<p> 17558 This issue may well be quite large. Language in para 4 about "if 17559 an lvalue" is wrong because types aren't expressions. 17560</p> 17561 17562<blockquote> 17563<p> 17564Maybe we should define the term "move" so we can just say in the 17565effects, "<tt>f</tt> is moved into the newly-created thread" or something, and 17566agree (and ideally document) that saying "<tt>f</tt> is moved" implies 17567</p> 17568 17569<blockquote><pre>F x(move(f)) 17570</pre></blockquote> 17571 17572<p> 17573is required to work. That would cover both ctors at once. 17574</p> 17575</blockquote> 17576 17577<p> 17578 p1199, call_once has all the same issues. 17579</p> 17580</blockquote> 17581<p> 17582[2009-03-21 Sat] p869 InputIterator pointer type should not be required 17583to be convertible to const value_type*, rather it needs to have a 17584operator-> of its own that can be used for the value type. 17585</p> 17586 17587<blockquote> 17588This one is serious and unrelated to the move issue. 17589</blockquote> 17590 17591<p> 17592[2009-03-21 Sat] p818 stack has the same problem with default ctor. 17593</p> 17594<p> 17595[2009-03-21 Sat] p816 priority_queue has the same sorts of problems as queue, only more so 17596</p> 17597<blockquote><pre> requires MoveConstructible<Cont> 17598 explicit priority_queue(const Compare& x = Compare(), Cont&& = Cont()); 17599</pre> 17600<p> 17601 Don't require MoveConstructible when default constructing Cont. 17602 Also missing semantics for move ctor. 17603</p> 17604</blockquote> 17605<p> 17606 [2009-03-21 Sat] Why are Allocators required to be CopyConstructible as 17607 opposed to MoveConstructible? 17608</p> 17609<p> 17610 [2009-03-21 Sat] p813 queue needs a separate default ctor (Cont needn't 17611 be MoveConstructible). No documented semantics for move c'tor. Or 17612 *any* of its 7 ctors! 17613</p> 17614<p> 17615 [2009-03-21 Sat] std::array should have constructors for C++0x, 17616 consequently must consider move construction. 17617</p> 17618 17619<p><i>[ 176202009-05-01 Daniel adds: 17621]</i></p> 17622 17623 17624<blockquote> 17625This could be done as part of <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1035">1035</a>, which already handles 17626deviation of <tt>std::array</tt> from container tables. 17627</blockquote> 17628 17629<p> 17630 [2009-03-21 Sat] p622 all messed up. 17631</p> 17632<blockquote> 17633<p> 17634 para 8 "implementation-defined" is the wrong term; should be "see 17635 below" or something. 17636</p> 17637<p> 17638 para 12 "will be selected" doesn't make any sense because we're not 17639 talking about actual arg types. 17640</p> 17641<p> 17642 paras 9-13 need to be totally rewritten for concepts. 17643</p> 17644</blockquote> 17645 17646<p> 17647 [2009-03-21 Sat] Null pointer comparisons (p587) have all become 17648 unconstrained. Need to fix that 17649</p> 17650<p> 17651 [2009-03-21 Sat] mem_fun_t etc. definition doesn't match declaration. 17652 We think CopyConstructible is the right reqt. 17653</p> 17654<p> 17655 make_pair needs Constructible<V1, T1&&> requirements! 17656</p> 17657<p> 17658 make_tuple needs something similar 17659</p> 17660<p> 17661 tuple bug in synopsis: 17662</p> 17663<blockquote><pre> template <class... UTypes> 17664 requires Constructible<Types, const UTypes&>... 17665 template <class... UTypes> 17666 requires Constructible<Types, RvalueOf<UTypes>::type>... 17667</pre> 17668<p> 17669 Note: removal of MoveConstructible requirements in std::function makes 17670 these routines unconstrained! 17671</p> 17672</blockquote> 17673 17674<p><i>[ 176752009-05-02 Daniel adds: 17676]</i></p> 17677 17678 17679<blockquote> 17680This part of the issue is already covered by <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1077">1077</a>. 17681</blockquote> 17682 17683<p> 17684 these unique_ptr constructors are broken [ I think this is covered in "p622 all messed up" ] 17685</p> 17686<blockquote><pre> unique_ptr(pointer p, implementation-defined d); 17687 unique_ptr(pointer p, implementation-defined d); 17688</pre></blockquote> 17689<p> 17690 multimap range constructor should not have MoveConstructible<value_type> requirement. 17691</p> 17692<blockquote> 17693 same with insert(..., P&&); multiset has the same issue, as do 17694 unordered_multiset and unordered_multimap. Review these! 17695</blockquote> 17696 17697</blockquote> 17698 17699<p><i>[ 17700Batavia (2009-05): 17701]</i></p> 17702 17703<blockquote> 17704Move to Open, pending proposed wording from Dave for further review. 17705</blockquote> 17706 17707<p><i>[ 177082009-10 post-Santa Cruz: 17709]</i></p> 17710 17711 17712<blockquote> 17713Tentatively NAD. We are not sure what has been addressed and what hasn't. 17714Recommend closing unless someone sorts this out into something more readable. 17715</blockquote> 17716 17717 17718 17719<p><b>Proposed resolution:</b></p> 17720<p> 17721</p> 17722 17723 17724 17725 17726 17727<hr> 17728<h3><a name="1100"></a>1100. <tt>auto_ptr</tt> to <tt>unique_ptr</tt> conversion</h3> 17729<p><b>Section:</b> 20.8.14.2.1 [unique.ptr.single.ctor] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 17730 <b>Submitter:</b> Howard Hinnant <b>Opened:</b> 2009-04-25 <b>Last modified:</b> 2009-10-21</p> 17731<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#unique.ptr.single.ctor">active issues</a> in [unique.ptr.single.ctor].</p> 17732<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#unique.ptr.single.ctor">issues</a> in [unique.ptr.single.ctor].</p> 17733<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 17734<p><b>Discussion:</b></p> 17735<p> 17736Message c++std-lib-23182 led to a discussion in which several people 17737expressed interest in being able to convert an <tt>auto_ptr</tt> to a 17738<tt>unique_ptr</tt> without the need to call <tt>release</tt>. Below is 17739wording to accomplish this. 17740</p> 17741 17742<p><i>[ 17743Batavia (2009-05): 17744]</i></p> 17745 17746<blockquote> 17747<p> 17748Pete believes it not a good idea to separate parts of a class's definition. 17749Therefore, if we do this, 17750it should be part of <tt>unique-ptr</tt>'s specification. 17751</p> 17752<p> 17753Alisdair believes the lvalue overload may be not necessary. 17754</p> 17755<p> 17756Marc believes it is more than just sugar, 17757as it does ease the transition to <tt>unique-ptr</tt>. 17758</p> 17759<p> 17760We agree with the resolution as presented. 17761Move to Tentatively Ready. 17762</p> 17763</blockquote> 17764 17765<p><i>[ 177662009-07 Frankfurt 17767]</i></p> 17768 17769 17770<blockquote> 17771Moved from Tentatively Ready to Open only because the wording needs to be 17772tweaked for concepts removal. 17773</blockquote> 17774 17775<p><i>[ 177762009-08-01 Howard deconceptifies wording: 17777]</i></p> 17778 17779 17780<blockquote> 17781I also moved the change from D.10 [depr.auto.ptr] 17782to 20.8.14.2 [unique.ptr.single] per the Editor's request 17783in Batavia (as long as I was making changes anyway). Set back 17784to Review. 17785</blockquote> 17786 17787<p><i>[ 177882009-10 Santa Cruz: 17789]</i></p> 17790 17791 17792<blockquote> 17793Move to Ready. 17794</blockquote> 17795 17796 17797 17798<p><b>Proposed resolution:</b></p> 17799<p> 17800Add to 20.8.14.2 [unique.ptr.single]: 17801</p> 17802 17803<blockquote><pre>template <class T, class D> 17804class unique_ptr 17805{ 17806public: 17807<ins> template <class U> 17808 unique_ptr(auto_ptr<U>& u); 17809 template <class U> 17810 unique_ptr(auto_ptr<U>&& u);</ins> 17811}; 17812</pre></blockquote> 17813 17814<p> 17815Add to 20.8.14.2.1 [unique.ptr.single.ctor]: 17816</p> 17817 17818<blockquote><pre>template <class U> 17819 unique_ptr(auto_ptr<U>& u); 17820template <class U> 17821 unique_ptr(auto_ptr<U>&& u); 17822</pre> 17823<blockquote> 17824<p> 17825<i>Effects:</i> Constructs a <tt>unique_ptr</tt> with <tt>u.release()</tt>. 17826</p> 17827 17828<p> 17829<i>Postconditions:</i> <tt>get() == </tt> the value <tt>u.get()</tt> had before 17830the construciton, modulo any required offset adjustments resulting from the cast from 17831<tt>U*</tt> to <tt>T*</tt>. <tt>u.get() == nullptr</tt>. 17832</p> 17833 17834<p> 17835<i>Throws:</i> nothing. 17836</p> 17837 17838<p> 17839<i>Remarks:</i> <tt>U*</tt> shall be implicitly convertible to <tt>T*</tt> and 17840<tt>D</tt> shall be the same type as <tt>default_delete<T></tt>, else these 17841constructors shall not participate in overload resolution. 17842</p> 17843</blockquote> 17844</blockquote> 17845 17846 17847 17848 17849 17850 17851<hr> 17852<h3><a name="1104"></a>1104. <tt>basic_ios::move</tt> should accept lvalues</h3> 17853<p><b>Section:</b> 27.5.4.2 [basic.ios.members] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 17854 <b>Submitter:</b> Howard Hinnant <b>Opened:</b> 2009-04-25 <b>Last modified:</b> 2009-10-20</p> 17855<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#basic.ios.members">active issues</a> in [basic.ios.members].</p> 17856<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#basic.ios.members">issues</a> in [basic.ios.members].</p> 17857<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 17858<p><b>Discussion:</b></p> 17859<p> 17860With the rvalue reference changes in 17861<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2844.html">N2844</a> 17862<tt>basic_ios::move</tt> no longer has the most convenient signature: 17863</p> 17864 17865<blockquote><pre>void move(basic_ios&& rhs); 17866</pre></blockquote> 17867 17868<p> 17869This signature should be changed to accept lvalues. It does not need to be 17870overloaded to accept rvalues. This is a special case that only derived clients 17871will see. The generic <tt>move</tt> still needs to accept rvalues. 17872</p> 17873 17874<p><i>[ 17875Batavia (2009-05): 17876]</i></p> 17877 17878<blockquote> 17879<p> 17880Tom prefers, on general principles, to provide both overloads. 17881Alisdair agrees. 17882</p> 17883<p> 17884Howard points out that there is no backward compatibility issue 17885as this is new to C++0X. 17886</p> 17887<p> 17888We agree that both overloads should be provided, 17889and Howard will provide the additional wording. 17890Move to Open. 17891</p> 17892</blockquote> 17893 17894<p><i>[ 178952009-05-23 Howard adds: 17896]</i></p> 17897 17898 17899<blockquote> 17900Added overload, moved to Review. 17901</blockquote> 17902 17903<p><i>[ 179042009 Santa Cruz: 17905]</i></p> 17906 17907 17908<blockquote> 17909Move to Ready. 17910</blockquote> 17911 17912 17913 17914<p><b>Proposed resolution:</b></p> 17915<p> 17916Add a signature to the existing prototype in the synopsis of 27.5.4 [ios] 17917and in 27.5.4.2 [basic.ios.members]: 17918</p> 17919 17920<blockquote><pre><ins>void move(basic_ios& rhs);</ins> 17921void move(basic_ios&& rhs); 17922</pre></blockquote> 17923 17924 17925 17926 17927 17928<hr> 17929<h3><a name="1106"></a>1106. Multiple exceptions from connected <tt>shared_future::get()</tt>?</h3> 17930<p><b>Section:</b> 30.6.7 [future.shared_future] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 17931 <b>Submitter:</b> Thomas J. Gritzan <b>Opened:</b> 2009-04-03 <b>Last modified:</b> 2009-05-23</p> 17932<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#future.shared_future">issues</a> in [future.shared_future].</p> 17933<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 17934<p><b>Discussion:</b></p> 17935<p> 17936It is not clear, if multiple threads are waiting in a 17937<tt>shared_future::get()</tt> call, if each will rethrow the stored exception. 17938</p> 17939<p> 17940Paragraph 9 reads: 17941</p> 17942<blockquote> 17943<i>Throws:</i> the stored exception, if an exception was stored and not 17944retrieved before. 17945</blockquote> 17946<p> 17947The "not retrieved before" suggests that only one exception is thrown, 17948but one exception for each call to <tt>get()</tt> is needed, and multiple calls 17949to <tt>get()</tt> even on the same <tt>shared_future</tt> object seem to be allowed. 17950</p> 17951<p> 17952I suggest removing "and not retrieved before" from the Throws paragraph. 17953I recommend adding a note that explains that multiple calls on <tt>get()</tt> are 17954allowed, and each call would result in an exception if an exception was 17955stored. 17956</p> 17957 17958<p><i>[ 17959Batavia (2009-05): 17960]</i></p> 17961 17962<blockquote> 17963<p> 17964We note there is a pending paper by Detlef 17965on such <tt>future</tt>-related issues; 17966we would like to wait for his paper before proceeding. 17967</p> 17968<p> 17969Alisdair suggests we may want language to clarify that this 17970<tt>get()</tt> function can be called from several threads 17971with no need for explicit locking. 17972</p> 17973<p> 17974Move to Open. 17975</p> 17976</blockquote> 17977 17978 17979<p><b>Proposed resolution:</b></p> 17980<p> 17981Change 30.6.7 [future.shared_future]: 17982</p> 17983 17984<blockquote><pre>const R& shared_future::get() const; 17985R& shared_future<R&>::get() const; 17986void shared_future<void>::get() const; 17987</pre> 17988<blockquote> 17989<p>...</p> 17990<p> 17991-9- <i>Throws:</i> the stored exception, if an exception was stored<del> and not retrieved before</del>. 17992<ins> 17993[<i>Note:</i> Multiple calls on <tt>get()</tt> are 17994allowed, and each call would result in an exception if an exception was 17995stored. — <i>end note</i>] 17996</ins> 17997</p> 17998</blockquote> 17999</blockquote> 18000 18001 18002 18003 18004 18005 18006<hr> 18007<h3><a name="1108"></a>1108. thread.req.exception overly constrains implementations</h3> 18008<p><b>Section:</b> 30.2.2 [thread.req.exception] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Tentatively Ready</a> 18009 <b>Submitter:</b> Christopher Kohlhoff <b>Opened:</b> 2009-04-25 <b>Last modified:</b> 2009-10-26</p> 18010<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20Ready">Tentatively Ready</a> status.</p> 18011<p><b>Discussion:</b></p> 18012<p> 18013The current formulation of 30.2.2 [thread.req.exception]/2 reads: 18014</p> 18015<blockquote> 18016The error_category of the <tt>error_code</tt> reported by such an 18017exception's <tt>code()</tt> member function is as specified in the error 18018condition Clause. 18019</blockquote> 18020<p> 18021This constraint on the code's associated <tt>error_categor</tt> means an 18022implementation must perform a mapping from the system-generated 18023error to a <tt>generic_category()</tt> error code. The problems with this 18024include: 18025</p> 18026 18027<ul> 18028<li> 18029The mapping is always performed, even if the resultant value is 18030 never used. 18031</li> 18032<li> 18033<p> 18034The original error produced by the operating system is lost. 18035</p> 18036</li> 18037</ul> 18038<p> 18039The latter was one of Peter Dimov's main objections (in a private 18040email discussion) to the original <tt>error_code</tt>-only design, and led to 18041the creation of <tt>error_condition</tt> in the first place. Specifically, 18042<tt>error_code</tt> and <tt>error_condition</tt> are intended to perform the following 18043roles: 18044</p> 18045<ul> 18046<li> 18047<tt>error_code</tt> holds the original error produced by the operating 18048 system. 18049</li> 18050<li> 18051<tt>error_condition</tt> and the generic category provide a set of well 18052 known error constants that error codes may be tested against. 18053</li> 18054</ul> 18055<p> 18056Any mapping determining correspondence of the returned error code to 18057the conditions listed in the error condition clause falls under the 18058"latitude" granted to implementors in 19.5.1.5 [syserr.errcat.objects]. 18059(Although obviously their latitude is restricted a little by the 18060need to match the right error condition when returning an error code 18061from a library function.) 18062</p> 18063<p> 18064It is important that this <tt>error_code/error_condition</tt> usage is done 18065correctly for the thread library since it is likely to set the 18066pattern for future TR libraries that interact with the operating 18067system. 18068</p> 18069 18070<p><i>[ 18071Batavia (2009-05): 18072]</i></p> 18073 18074<blockquote> 18075Move to Open, and recommend the issue be deferred until after the next 18076Committee Draft is issued. 18077</blockquote> 18078 18079<p><i>[ 180802009-10 post-Santa Cruz: 18081]</i></p> 18082 18083 18084<blockquote> 18085Move to Tentatively Ready. 18086</blockquote> 18087 18088 18089 18090<p><b>Proposed resolution:</b></p> 18091<p> 18092Change 30.2.2 [thread.req.exception]/2: 18093</p> 18094 18095<blockquote> 18096<p> 18097-2- <del>The <tt>error_category</tt> (19.5.1.1) of the <tt>error_code</tt> reported by 18098such an exception's <tt>code()</tt> member function 18099is as specified in the error condition Clause.</del> 18100<ins> 18101The <tt>error_code</tt> reported by such an exception's <tt>code()</tt> member 18102function shall compare equal to one of the conditions specified in 18103the function's error condition Clause. [<i>Example:</i> When the thread 18104constructor fails: 18105</ins> 18106</p> 18107<blockquote><pre><ins> 18108ec.category() == implementation-defined // probably system_category 18109ec == errc::resource_unavailable_try_again // holds true 18110</ins></pre></blockquote> 18111 18112<p><ins> 18113— <i>end example</i>] 18114</ins></p> 18115 18116</blockquote> 18117 18118 18119 18120 18121 18122 18123<hr> 18124<h3><a name="1110"></a>1110. Is <tt>for_each</tt> overconstrained?</h3> 18125<p><b>Section:</b> 25.2.4 [alg.foreach] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 18126 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-04-29 <b>Last modified:</b> 2009-10-27</p> 18127<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#alg.foreach">issues</a> in [alg.foreach].</p> 18128<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 18129<p><b>Discussion:</b></p> 18130<p> 18131Quoting working paper for reference (25.2.4 [alg.foreach]): 18132</p> 18133 18134<blockquote> 18135<pre>template<InputIterator Iter, Callable<auto, Iter::reference> Function> 18136 requires CopyConstructible<Function> 18137 Function for_each(Iter first, Iter last, Function f); 18138</pre> 18139<blockquote> 18140<p> 181411 Effects: Applies f to the result of dereferencing every iterator in the 18142 range [first,last), starting from first and proceeding to last - 1. 18143</p> 18144<p> 181452 Returns: f. 18146</p> 18147<p> 181483 Complexity: Applies f exactly last - first times. 18149</p> 18150</blockquote> 18151</blockquote> 18152 18153<p> 18154P2 implies the passed object <tt>f</tt> should be invoked at each stage, rather than 18155some copy of <tt>f</tt>. This is important if the return value is to usefully 18156accumulate changes. So the requirements are an object of type <tt>Function</tt> can 18157be passed-by-value, invoked multiple times, and then return by value. In 18158this case, <tt>MoveConstructible</tt> is sufficient. This would open support for 18159move-only functors, which might become important in concurrent code as you 18160can assume there are no other references (copies) of a move-only type and so 18161freely use them concurrently without additional locks. 18162</p> 18163 18164<p><i>[ 18165See further discussion starting with c++std-lib-23686. 18166]</i></p> 18167 18168 18169<p><i>[ 18170Batavia (2009-05): 18171]</i></p> 18172 18173<blockquote> 18174<p> 18175Pete suggests we may want to look at this in a broader context 18176involving other algorithms. 18177We should also consider the implications of parallelism. 18178</p> 18179<p> 18180Move to Open, and recommend the issue be deferred until after the next 18181Committee Draft is issued. 18182</p> 18183</blockquote> 18184 18185<p><i>[ 181862009-10-14 Daniel de-conceptified the proposed resolution. 18187]</i></p> 18188 18189 18190<blockquote> 18191<p> 18192The note in 25.1 [algorithms.general]/9 already says the right thing: 18193</p> 18194<blockquote> 18195Unless otherwise specified, algorithms that take function objects 18196as arguments are permitted to copy those function objects freely. 18197</blockquote> 18198<p> 18199So we only need to ensure that the wording for <tt>for_each</tt> is sufficiently 18200clear, which is the intend of the following rewording. 18201</p> 18202</blockquote> 18203 18204<p><i>[ 182052009-10-15 Daniel proposes: 18206]</i></p> 18207 18208 18209<blockquote> 18210<ul> 18211<li> 18212<p> 18213Add a new Requires clause just after the prototype declaration (25.2.4 [alg.foreach]): 18214</p> 18215<blockquote> 18216<p> 18217<ins><i>Requires:</i> <tt>Function</tt> shall be <tt>MoveConstructible</tt> 18218( [moveconstructible]), <tt>CopyConstructible</tt> is not required.</ins> 18219</p> 18220</blockquote> 18221</li> 18222<li> 18223<p> 18224Change 25.2.4 [alg.foreach]/2 as indicated: 18225</p> 18226 18227<blockquote> 18228<i>Returns:</i> <ins>std::move(</ins>f<ins>)</ins>. 18229</blockquote> 18230</li> 18231</ul> 18232</blockquote> 18233 18234<p><i>[ 182352009-10 post-Santa Cruz: 18236]</i></p> 18237 18238 18239<blockquote> 18240Move to Tentatively Ready, using Daniel's wording without the portion 18241saying "CopyConstructible is not required". 18242</blockquote> 18243 18244<p><i>[ 182452009-10-27 Daniel adds: 18246]</i></p> 18247 18248 18249<blockquote> 18250<p> 18251I see that during the Santa Cruz meeting the originally proposed addition 18252</p> 18253 18254<blockquote> 18255, <tt>CopyConstructible</tt> is not required. 18256</blockquote> 18257 18258<p> 18259was removed. I don't think that this removal was a good idea. The combination 18260of 25.1 [algorithms.general]/9 18261</p> 18262 18263<blockquote> 18264[<i>Note:</i> Unless otherwise specified, algorithms that take function objects 18265as arguments are permitted to copy those function objects freely.[..] 18266</blockquote> 18267 18268<p> 18269with the fact that <tt>CopyConstructible</tt> is a refinement <tt>MoveConstructible</tt> 18270makes it necessary that such an explicit statement is given. Even the 18271existence of the usage of <tt>std::move</tt> in the <i>Returns</i> clause doesn't 18272help much, because this would still be well-formed for a <tt>CopyConstructible</tt> 18273without move constructor. Let me add that the originally proposed 18274addition reflects current practice in the standard, e.g. 25.3.9 [alg.unique]/5 18275usages a similar terminology. 18276</p> 18277 18278<p> 18279For similar wording need in case for auto_ptr see <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#973">973</a>. 18280</p> 18281 18282<p><i>[ 18283Howard: Moved from Tentatively Ready to Open. 18284]</i></p> 18285 18286</blockquote> 18287 18288 18289 18290<p><b>Proposed resolution:</b></p> 18291<ul> 18292<li> 18293<p> 18294Add a new Requires clause just after the prototype declaration (25.2.4 [alg.foreach]): 18295</p> 18296<blockquote> 18297<p> 18298<ins><i>Requires:</i> <tt>Function</tt> shall be <tt>MoveConstructible</tt> 18299( [moveconstructible]).</ins> 18300</p> 18301</blockquote> 18302</li> 18303<li> 18304<p> 18305Change 25.2.4 [alg.foreach]/2 as indicated: 18306</p> 18307 18308<blockquote> 18309<i>Returns:</i> <ins>std::move(</ins>f<ins>)</ins>. 18310</blockquote> 18311</li> 18312</ul> 18313 18314 18315 18316 18317 18318 18319 18320 18321<hr> 18322<h3><a name="1112"></a>1112. bitsets and new style for loop</h3> 18323<p><b>Section:</b> 20.3.7 [template.bitset] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Future">Tentatively NAD Future</a> 18324 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-05-06 <b>Last modified:</b> 2009-10-26</p> 18325<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#template.bitset">active issues</a> in [template.bitset].</p> 18326<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#template.bitset">issues</a> in [template.bitset].</p> 18327<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20NAD%20Future">Tentatively NAD Future</a> status.</p> 18328<p><b>Discussion:</b></p> 18329<p> 18330<tt>Std::bitset</tt> is a homogeneous container-like sequence of bits, yet it does 18331not model the Range concept so cannot be used with the new for-loop syntax. 18332It is the only such type in the library that does NOT support the new for 18333loop. 18334</p> 18335<p> 18336The obvious reason is that bitset does not support iterators. 18337</p> 18338<p> 18339At least two reasonable solutions are available: 18340</p> 18341<ol type="i"> 18342<li> 18343Add an iterator interface to <tt>bitset</tt>, bringing its interface close to that 18344of <tt>std::array</tt> 18345</li> 18346<li> 18347Provide an unspecified concept_map for <tt>Range<bitset></tt>. 18348</li> 18349</ol> 18350<p> 18351The latter will still need some kind of iterator-like adapter for <tt>bitset</tt>, 18352but gives implementers greater freedom on the details. E.g. begin/end return 18353some type that simply invokes <tt>operator[]</tt> on the object it wraps, and 18354increments its index on <tt>operator++</tt>. A vendor can settle for <tt>InputIterator</tt> 18355support, rather than wrapping up a full <tt>RandomAccessIterator</tt>. 18356</p> 18357<p> 18358I have a mild preference for option (ii) as I think it is less work to 18359specify at this stage of the process, although (i) is probably more useful 18360in the long run. 18361</p> 18362<p> 18363Hmm, my wording looks a little woolly, as it does not say what the element 18364type of the range is. Do I get a range of <tt>bool</tt>, <tt>bitset<N>::reference</tt>, or 18365something else entirely? 18366</p> 18367<p> 18368I guess most users will assume the behaviour of reference, but expect to 18369work with <tt>bool</tt>. <tt>Bool</tt> is OK for read-only traversal, but you really need to 18370take a reference to a <tt>bitset::reference</tt> if you want to write back. 18371</p> 18372 18373<p><i>[ 18374Batavia (2009-05): 18375]</i></p> 18376 18377<blockquote> 18378Move to Open. 18379We further recommend this be deferred until after the next Committee Draft. 18380</blockquote> 18381 18382<p><i>[ 183832009-05-25 Alisdair adds: 18384]</i></p> 18385 18386 18387<blockquote> 18388<p> 18389I just stumbled over the <tt>Range concept_map</tt> for <tt>valarray</tt> and this should 18390probably set the precedent on how to write the wording. 18391</p> 18392 18393<p><i>[ 18394Howard: I've replaced the proposed wording with Alisdair's suggestion. 18395]</i></p> 18396 18397 18398</blockquote> 18399 18400<p><i>[ 184012009-07-24 Daniel modifies the proposed wording for non-concepts. 18402]</i></p> 18403 18404 18405<p><i>[ 184062009-10 post-Santa Cruz: 18407]</i></p> 18408 18409 18410<blockquote> 18411Mark as Tentatively NAD Future due to the loss of concepts. 18412</blockquote> 18413 18414 18415 18416<p><b>Proposed resolution:</b></p> 18417<ol> 18418<li> 18419<p> 18420Modify the section 20.3.7 [template.bitset] <tt><bitset></tt> synopsis by adding 18421the following at the end of the synopsis: 18422</p> 18423<blockquote><pre><ins> 18424// XX.X.X bitset range access [bitset.range] 18425template<size_t N> <i>unspecified-1</i> begin(bitset<N>&); 18426template<size_t N> <i>unspecified-2</i> begin(const bitset<N>&); 18427template<size_t N> <i>unspecified-1</i> end(bitset<N>&); 18428template<size_t N> <i>unspecified-2</i> end(const bitset<N>&); 18429</ins> 18430</pre></blockquote> 18431</li> 18432<li> 18433<p> 18434Add a new section <ins>"bitset range access" [bitset.range]</ins> 18435after the current section 20.3.7.3 [bitset.operators] with the following series of 18436paragraphs: 18437</p> 18438<blockquote> 18439<p> 18440<ins> 184411. In the <tt>begin</tt> and <tt>end</tt> function templates that follow, <i>unspecified-1</i> 18442is a type that meets the requirements of a mutable random access 18443iterator (24.2.5 [random.access.iterators]) whose <tt>value_type</tt> is <tt>bool</tt> and 18444whose reference type is <tt>bitset<N>::reference</tt>. 18445<i>unspecified-2</i> is a type that meets the requirements of a constant 18446random access iterator (24.2.5 [random.access.iterators]) whose <tt>value_type</tt> 18447is <tt>bool</tt> and whose reference type is <tt>bool</tt>. 18448</ins> 18449</p> 18450<pre><ins> 18451template<size_t N> <i>unspecified-1</i> begin(bitset<N>&); 18452template<size_t N> <i>unspecified-2</i> begin(const bitset<N>&); 18453</ins> 18454</pre> 18455<blockquote> 18456<ins>2. Returns: an iterator referencing the first bit in the bitset.</ins> 18457</blockquote> 18458 18459<pre><ins> 18460template<size_t N> <i>unspecified-1</i> end(bitset<N>&); 18461template<size_t N> <i>unspecified-2</i> end(const bitset<N>&); 18462</ins></pre> 18463 18464<blockquote> 18465<ins>3. Returns: an iterator referencing one past the last bit in the 18466bitset.</ins> 18467</blockquote> 18468</blockquote> 18469</li> 18470</ol> 18471 18472 18473 18474 18475 18476 18477 18478 18479 18480 18481 18482 18483<hr> 18484<h3><a name="1113"></a>1113. <tt>bitset::to_string</tt> could be simplified</h3> 18485<p><b>Section:</b> 20.3.7 [template.bitset] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Tentatively Ready</a> 18486 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-05-09 <b>Last modified:</b> 2009-10-26</p> 18487<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#template.bitset">active issues</a> in [template.bitset].</p> 18488<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#template.bitset">issues</a> in [template.bitset].</p> 18489<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20Ready">Tentatively Ready</a> status.</p> 18490<p><b>Discussion:</b></p> 18491<p> 18492In <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#853">853</a> our resolution is changing the signature by adding two 18493defaulting arguments to 3 calls. In principle, this means that ABI breakage 18494is not an issue, while API is preserved. 18495</p> 18496<p> 18497With that observation, it would be very nice to use the new ability to 18498supply default template parameters to function templates to collapse all 3 18499signatures into 1. In that spirit, this issue offers an alternative resolution 18500than that of <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#853">853</a>. 18501</p> 18502 18503<p><i>[ 18504Batavia (2009-05): 18505]</i></p> 18506 18507<blockquote> 18508Move to Open, 18509and look at the issue again after <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#853">853</a> has been accepted. 18510We further recommend this be deferred until after the next Committee Draft. 18511</blockquote> 18512 18513<p><i>[ 185142009-10 post-Santa Cruz: 18515]</i></p> 18516 18517 18518<blockquote> 18519Move to Tentatively Ready. 18520</blockquote> 18521 18522 18523 18524<p><b>Proposed resolution:</b></p> 18525 18526<ol type="A"> 18527<li> 18528<p> 18529In 20.3.7 [template.bitset]/1 (class bitset) ammend: 18530</p> 18531<blockquote><pre>template <class charT <ins>= char</ins>, 18532 class traits <ins>= char_traits<charT></ins>, 18533 class Allocator <ins>= allocator<charT></ins>> 18534 basic_string<charT, traits, Allocator> 18535 to_string(charT zero = charT('0'), charT one = charT('1')) const; 18536<del>template <class charT, class traits> 18537 basic_string<charT, traits, allocator<charT> > to_string() const; 18538template <class charT> 18539 basic_string<charT, char_traits<charT>, allocator<charT> > to_string() const; 18540basic_string<char, char_traits<char>, allocator<char> > to_string() const;</del> 18541</pre></blockquote> 18542</li> 18543<li> 18544<p> 18545In 20.3.7.2 [bitset.members] prior to p35 ammend: 18546</p> 18547<blockquote><pre>template <class charT <ins>= char</ins>, 18548 class traits <ins>= char_traits<charT></ins>, 18549 class Allocator <ins>= allocator<charT></ins>> 18550 basic_string<charT, traits, Allocator> 18551 to_string(charT zero = charT('0'), charT one = charT('1')) const; 18552</pre></blockquote> 18553</li> 18554<li> 18555Strike 20.3.7.2 [bitset.members] paragraphs 37 -> 39 (including signature 18556above 37) 18557</li> 18558</ol> 18559 18560 18561 18562 18563 18564 18565<hr> 18566<h3><a name="1114"></a>1114. Type traits underspecified</h3> 18567<p><b>Section:</b> 20.6 [meta] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Tentatively Ready</a> 18568 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2009-05-12 <b>Last modified:</b> 2009-10-26</p> 18569<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#meta">issues</a> in [meta].</p> 18570<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20Ready">Tentatively Ready</a> status.</p> 18571<p><b>Discussion:</b></p> 18572 18573<p> 18574Related to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#975">975</a> and <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1023">1023</a>. 18575</p> 18576 18577<p> 18578The current wording in 20.6.1 [meta.rqmts] is still unclear concerning 18579it's requirements on the type traits classes regarding ambiguities. 18580Specifically it's unclear 18581</p> 18582 18583<ul> 18584<li> 18585if a predicate trait (20.6.4 [meta.unary], 20.6.5 [meta.rel]) could derive from both 18586<tt>true_type</tt>/<tt>false_type</tt>. 18587</li> 18588<li> 18589if any of the type traits (20.6.1 [meta.rqmts], 20.6.4 [meta.unary], 20.6.5 [meta.rel]) could ambiguously derive 18590from the same specified result type. 18591</li> 18592<li> 18593if any of the type traits (20.6.1 [meta.rqmts], 20.6.4 [meta.unary], 20.6.5 [meta.rel]) could derive from other 18594<tt>integral_constant</tt> types making the contained names ambiguous 18595</li> 18596<li> 18597if any of the type traits (20.6.1 [meta.rqmts], 20.6.4 [meta.unary], 20.6.5 [meta.rel]) could have other base 18598classes that contain members hiding the name of the result type members 18599or make the contained member names ambiguous. 18600</li> 18601</ul> 18602 18603<p><i>[ 18604Batavia (2009-05): 18605]</i></p> 18606 18607<blockquote> 18608<p> 18609Alisdair would prefer to factor some of the repeated text, 18610but modulo a corner case or two, 18611he believes the proposed wording is otherwise substantially correct. 18612</p> 18613<p> 18614Move to Open. 18615</p> 18616</blockquote> 18617 18618<p><i>[ 186192009-10 post-Santa Cruz: 18620]</i></p> 18621 18622 18623<blockquote> 18624Move to Tentatively Ready. 18625</blockquote> 18626 18627 18628 18629<p><b>Proposed resolution:</b></p> 18630<p><i>[ 18631The usage of the notion of a <i>BaseCharacteristic</i> below 18632might be 18633useful in other places - e.g. to define the base class relation in 1863420.7.5 [refwrap], 20.7.14 [func.memfn], or 20.7.15.2 [func.wrap.func]. 18635In this case it's definition should probably 18636be moved to Clause 17 18637]</i></p> 18638 18639 18640<ol> 18641<li> 18642<p> 18643Change 20.6.1 [meta.rqmts]/1 as indicated: 18644</p> 18645<blockquote> 18646[..] It shall be <tt>DefaultConstructible</tt>, <tt>CopyConstructible</tt>, and publicly 18647<ins>and unambiguously</ins> derived, directly or indirectly, from 18648<ins>its <i>BaseCharacteristic</i>, which is</ins> a specialization of the 18649template <tt>integral_constant</tt> (20.6.3), with the arguments to the template 18650<tt>integral_constant</tt> determined by the requirements for the particular 18651property being described. <ins>The member names of the 18652<i>BaseCharacteristic</i> shall be unhidden and unambiguously 18653available in the <i>UnaryTypeTrait</i>.</ins> 18654</blockquote> 18655</li> 18656<li> 18657<p> 18658Change 20.6.1 [meta.rqmts]/2 as indicated: 18659</p> 18660<blockquote> 18661[..] It shall be <tt>DefaultConstructible</tt>, <tt>CopyConstructible</tt>, and publicly 18662<ins>and unambiguously</ins> derived, directly or indirectly, from 18663<del>an instance</del> <ins>its <i>BaseCharacteristic</i>, which is a 18664specialization</ins> of the template <tt>integral_constant</tt> (20.6.3), with 18665the arguments to the template <tt>integral_constant</tt> determined by the 18666requirements for the particular relationship being described. <ins>The 18667member names of the <i>BaseCharacteristic</i> shall be unhidden 18668and unambiguously available in the <i>BinaryTypeTrait</i>.</ins> 18669</blockquote> 18670</li> 18671<li> 18672<p> 18673Change 20.6.4 [meta.unary]/2 as indicated: 18674</p> 18675<blockquote> 18676Each of these templates shall be a <i>UnaryTypeTrait</i> (20.6.1), 18677<del>publicly derived directly or indirectly from <tt>true_type</tt> if the 18678corresponding condition is true, otherwise from <tt>false_type</tt></del> 18679<ins>where its <i>BaseCharacteristic</i> shall be <tt>true_type</tt> if the 18680corresponding condition is true, otherwise <tt>false_type</tt></ins>. 18681</blockquote> 18682</li> 18683<li> 18684<p> 18685Change 20.6.5 [meta.rel]/2 as indicated: 18686</p> 18687 18688<blockquote> 18689Each of these templates shall be a <i>BinaryTypeTrait</i> (20.6.1), 18690<del>publicly derived directly or indirectly from <tt>true_type</tt> if the 18691corresponding condition is true, otherwise from <tt>false_type</tt></del> 18692<ins>where its <i>BaseCharacteristic</i> shall be <tt>true_type</tt> if the 18693corresponding condition is true, otherwise <tt>false_type</tt></ins>. 18694</blockquote> 18695</li> 18696</ol> 18697 18698 18699 18700 18701 18702 18703<hr> 18704<h3><a name="1115"></a>1115. <tt>va_copy</tt> missing from Standard macros table</h3> 18705<p><b>Section:</b> C.2 [diff.library] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">Tentatively NAD Editorial</a> 18706 <b>Submitter:</b> Miles Zhao <b>Opened:</b> 2009-05-23 <b>Last modified:</b> 2009-10-26</p> 18707<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#diff.library">issues</a> in [diff.library].</p> 18708<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20NAD%20Editorial">Tentatively NAD Editorial</a> status.</p> 18709<p><b>Discussion:</b></p> 18710<p> 18711In "Table 122 -- Standard macros" of C.2 [diff.library], which lists the 56 macros 18712inherited from C library, <tt>va_copy</tt> seems to be missing. But in 18713"Table 21 -- Header <tt><cstdarg></tt> synopsis" (18.10 [support.runtime]), there is. 18714</p> 18715 18716<p><i>[ 187172009-10 post-Santa Cruz: 18718]</i></p> 18719 18720 18721<blockquote> 18722Mark as Tentatively NAD Editorial, if Pete disagrees, Howard 18723will move to Tentatively Ready 18724</blockquote> 18725 18726 18727 18728<p><b>Proposed resolution:</b></p> 18729<p> 18730Add <tt>va_copy</tt> to Table 122 -- Standard macros in C.2 [diff.library]. 18731</p> 18732 18733 18734 18735 18736 18737<hr> 18738<h3><a name="1118"></a>1118. tuple query APIs do not support cv-qualification</h3> 18739<p><b>Section:</b> 20.5.2.5 [tuple.helper] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 18740 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-05-23 <b>Last modified:</b> 2009-10-26</p> 18741<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#tuple.helper">active issues</a> in [tuple.helper].</p> 18742<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#tuple.helper">issues</a> in [tuple.helper].</p> 18743<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 18744<p><b>Discussion:</b></p> 18745<p> 18746The APIs <tt>tuple_size</tt> and <tt>tuple_element</tt> do not support 18747cv-qualified <tt>tuple</tt>s, <tt>pair</tt>s or <tt>array</tt>s. 18748</p> 18749<p> 18750The most generic solution would be to supply partial specializations once 18751for each cv-type in the <tt>tuple</tt> header. However, requiring this header for 18752cv-qualified <tt>pair</tt>s/<tt>array</tt>s seems unhelpful. The BSI editorial 18753suggestion (UK-198/US-69, 18754<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2533.html">N2533</a>) 18755to merge <tt>tuple</tt> into <tt><utility></tt> would help with <tt>pair</tt>, 18756but not <tt>array</tt>. That might be resolved by making a dependency between the 18757<tt><array></tt> header and <tt><utility></tt>, or simply recognising 18758the dependency be fulfilled in a Remark. 18759</p> 18760 18761<p><i>[ 187622009-05-24 Daniel adds: 18763]</i></p> 18764 18765 18766<blockquote> 18767<p> 18768All <tt>tuple_size</tt> templates with a base class need to derive publicly, e.g. 18769</p> 18770 18771<blockquote><pre>template <IdentityOf T> class tuple_size< const T > : 18772 <ins>public</ins> tuple_size<T> {}; 18773</pre></blockquote> 18774 18775<p> 18776The same applies to the tuple_element class hierarchies. 18777</p> 18778<p> 18779What is actually meant with the comment 18780</p> 18781<blockquote> 18782this solution relies on 'metafunction forwarding' to inherit the 18783nested typename type 18784</blockquote> 18785<p> 18786? 18787</p> 18788<p> 18789I ask, because all base classes are currently unconstrained and their 18790instantiation is invalid in the constrained context of the <tt>tuple_element</tt> partial 18791template specializations. 18792</p> 18793</blockquote> 18794 18795<p><i>[ 187962009-05-24 Alisdair adds: 18797]</i></p> 18798 18799 18800<blockquote> 18801<p> 18802I think a better solution might be to ask Pete editorially to change all 18803declarations of tupling APIs to use the struct specifier instead of class. 18804</p> 18805<p> 18806"metafunction forwarding" refers to the MPL metafunction protocol, where a 18807metafunction result is declared as a nested typedef with the name "type", 18808allowing metafunctions to be chained by means of inheritance. It is a 18809neater syntax than repeatedly declaring a typedef, and inheritance syntax is 18810slightly nicer when it comes to additional typename keywords. 18811</p> 18812<p> 18813The constrained template with an unconstrained base is a good observation 18814though. 18815</p> 18816</blockquote> 18817 18818<p><i>[ 188192009-10 post-Santa Cruz: 18820]</i></p> 18821 18822 18823<blockquote> 18824Move to Open, Alisdair to provide wording. Once wording is 18825provided, Howard will move to Review. 18826</blockquote> 18827 18828 18829 18830<p><b>Proposed resolution:</b></p> 18831<p> 18832Add to 20.5.1 [tuple.general] p2 (Header <tt><tuple></tt> synopsis) 18833</p> 18834 18835<blockquote><pre>// 20.5.2.3, tuple helper classes: 18836template <IdentityOf T> class tuple_size; // undefined 18837<ins>template <IdentityOf T> class tuple_size< const T > : tuple_size<T> {};</ins> 18838<ins>template <IdentityOf T> class tuple_size< volatile T > : tuple_size<T> {};</ins> 18839<ins>template <IdentityOf T> class tuple_size< const volatile T > : tuple_size<T> {};</ins> 18840 18841template <VariableType... Types> class tuple_size<tuple<Types...> >; 18842 18843template <size_t I, IdentityOf T> class tuple_element; // undefined 18844<ins>template <size_t I, IdentityOf T> class tuple_element<I, const T>;</ins> 18845<ins>template <size_t I, IdentityOf T> class tuple_element<I, volatile T>;</ins> 18846<ins>template <size_t I, IdentityOf T> class tuple_element<I, const volatile T>;</ins> 18847 18848template <size_t I, VariableType... Types> 18849 requires True<(I < sizeof...(Types))> class tuple_element<I, tuple<Types...> >; 18850</pre></blockquote> 18851 18852<p> 18853Add to 20.5.2.5 [tuple.helper] 18854</p> 18855<p><i>[ 18856(note that this solution relies on 'metafunction forwarding' to inherit the 18857nested typename type) 18858]</i></p> 18859 18860 18861<blockquote><pre>template <class... Types> 18862class tuple_size<tuple<Types...> > 18863 : public integral_constant<size_t, sizeof...(Types)> { }; 18864 18865template <size_t I, class... Types> 18866requires True<(I < sizeof...(Types))> 18867class tuple_element<I, tuple<Types...> > { 18868public: 18869 typedef TI type; 18870}; 18871 18872<ins>template <size_t I, IdentityOf T> 18873 class tuple_element<I, const T> : add_const<tuple_element<I,T>> {};</ins> 18874 18875<ins>template <size_t I, IdentityOf T> 18876 class tuple_element<I, volatile T> : add_volatile<tuple_element<I,T>> {};</ins> 18877 18878<ins>template <size_t I, IdentityOf T> 18879 class tuple_element<I, const volatile T> : add_cv<tuple_element<I,T>> {};</ins> 18880</pre></blockquote> 18881 18882 18883 18884 18885 18886<hr> 18887<h3><a name="1119"></a>1119. tuple query APIs do not support references</h3> 18888<p><b>Section:</b> 20.5.2.5 [tuple.helper] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 18889 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-05-23 <b>Last modified:</b> 2009-10-26</p> 18890<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#tuple.helper">active issues</a> in [tuple.helper].</p> 18891<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#tuple.helper">issues</a> in [tuple.helper].</p> 18892<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 18893<p><b>Discussion:</b></p> 18894<p> 18895The <tt>tuple</tt> query APIs <tt>tuple_size</tt> and 18896<tt>tuple_element</tt> do not support references-to-tuples. This can be 18897annoying when a template deduced a parameter type to be a reference, 18898which must be explicitly stripped with <tt>remove_reference</tt> before calling 18899these APIs. 18900</p> 18901<p> 18902I am not proposing a resolution at this point, as there is a 18903combinatorial explosion with lvalue/rvalue references and 18904cv-qualification (see previous issue) that suggests some higher 18905refactoring is in order. This might be something to kick back over to 18906Core/Evolution. 18907</p> 18908<p> 18909Note that we have the same problem in numeric_limits. 18910</p> 18911 18912<p><i>[ 189132009-10 post-Santa Cruz: 18914]</i></p> 18915 18916 18917<blockquote> 18918Move to Open. Alisdair to provide wording. 18919</blockquote> 18920 18921 18922 18923<p><b>Proposed resolution:</b></p> 18924 18925 18926 18927 18928 18929<hr> 18930<h3><a name="1121"></a>1121. Support for multiple arguments</h3> 18931<p><b>Section:</b> 20.4.2 [ratio.arithmetic] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Future">Tentatively NAD Future</a> 18932 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-05-25 <b>Last modified:</b> 2009-11-02</p> 18933<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#ratio.arithmetic">issues</a> in [ratio.arithmetic].</p> 18934<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20NAD%20Future">Tentatively NAD Future</a> status.</p> 18935<p><b>Discussion:</b></p> 18936<p> 18937Both add and multiply could sensibly be called with more than two arguments. 18938The variadic template facility makes such declarations simple, and is likely 18939to be frequently wrapped by end users if we do not supply the variant 18940ourselves. 18941</p> 18942<p> 18943We deliberately ignore divide at this point as it is not transitive. 18944Likewise, subtract places special meaning on the first argument so I do not 18945suggest extending that immediately. Both could be supported with analogous 18946wording to that for add/multiply below. 18947</p> 18948<p> 18949Note that the proposed resolution is potentially incompatible with that 18950proposed for <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#921">921</a>, although the addition of the typedef to ratio would be 18951equally useful. 18952</p> 18953 18954<p><i>[ 189552009-10-30 Alisdair adds: 18956]</i></p> 18957 18958 18959<blockquote> 18960<p> 18961The consensus of the group when we reviewed this in Santa Cruz was that 18962<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#921">921</a> would proceed to Ready as planned, and the 18963multi-paramater add/multiply templates should be renamed as 18964<tt>ratio_sum</tt> and <tt>ratio_product</tt> to avoid the problem 18965mixing template aliases with partial specializations. 18966</p> 18967 18968<p> 18969It was also suggested to close this issue as NAD Future as it does not 18970correspond directly to any NB comment. NBs are free to submit a 18971specific comment (and re-open) in CD2 though. 18972</p> 18973 18974<p> 18975Walter Brown also had concerns on better directing the order of 18976evaluation to avoid overflows if we do proceed for 0x rather than TR1, 18977so wording may not be complete yet. 18978</p> 18979 18980<p><i>[ 18981Alisdair updates wording. 18982]</i></p> 18983 18984 18985</blockquote> 18986 18987<p><i>[ 189882009-10-30 Howard: 18989]</i></p> 18990 18991 18992<blockquote> 18993Moved to Tentatively NAD Future after 5 positive votes on c++std-lib. 18994</blockquote> 18995 18996 18997 18998<p><b>Proposed resolution:</b></p> 18999 19000<p> 19001Add the following type traits to p3 20.4 [ratio] 19002</p> 19003 19004<blockquote><pre>// ratio arithmetic 19005template <class R1, class R2> struct ratio_add; 19006template <class R1, class R2> struct ratio_subtract; 19007template <class R1, class R2> struct ratio_multiply; 19008template <class R1, class R2> struct ratio_divide; 19009<ins>template <class R1, class ... RList> struct ratio_sum;</ins> 19010<ins>template <class R1, class ... RList> struct ratio_product;</ins> 19011</pre></blockquote> 19012 19013<p> 19014after 20.4.2 [ratio.arithmetic] p1: add 19015</p> 19016 19017<blockquote><pre>template <class R1, class ... RList> struct ratio_sum; // declared, never defined 19018 19019template <class R1> struct ratio_sum<R1> : R1 {}; 19020</pre> 19021 19022<blockquote> 19023<i>Requires:</i> <tt>R1</tt> is a specialization of class template <tt>ratio</tt> 19024</blockquote> 19025 19026<pre>template <class R1, class R2, class ... RList> 19027 struct ratio_sum<R1, R2, RList...> 19028 : ratio_add< R1, ratio_sum<R2, RList...>> { 19029}; 19030</pre> 19031 19032<blockquote> 19033<i>Requires:</i> <tt>R1</tt> and each element in parmater pack 19034<tt>RList</tt> is a specialization of class template <tt>ratio</tt> 19035</blockquote> 19036</blockquote> 19037 19038<p> 19039after 20.4.2 [ratio.arithmetic] p3: add 19040</p> 19041 19042<blockquote><pre>template <class R1, class ... RList> struct ratio_product; // declared, never defined 19043 19044template <class R1> struct ratio_product<R1> : R1 {}; 19045</pre> 19046 19047<blockquote> 19048<i>Requires:</i> <tt>R1</tt> is a specialization of class template <tt>ratio</tt> 19049</blockquote> 19050 19051<pre>template <class R1, class R2, class ... RList> 19052 struct ratio_sum<R1, R2, RList...> 19053 : ratio_add< R1, ratio_product<R2, RList...>> { 19054}; 19055</pre> 19056 19057<blockquote> 19058<i>Requires:</i> <tt>R1</tt> and each element in parmater pack 19059<tt>RList</tt> is a specialization of class template <tt>ratio</tt> 19060</blockquote> 19061</blockquote> 19062 19063 19064 19065 19066 19067 19068 19069 19070<hr> 19071<h3><a name="1123"></a>1123. no requirement that standard streams be flushed</h3> 19072<p><b>Section:</b> 27.5.2.1.6 [ios::Init] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 19073 <b>Submitter:</b> James Kanze <b>Opened:</b> 2009-05-14 <b>Last modified:</b> 2009-10-20</p> 19074<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#ios::Init">issues</a> in [ios::Init].</p> 19075<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 19076<p><b>Discussion:</b></p> 19077<p> 19078As currently formulated, the standard doesn't require that there 19079is ever a flush of <tt>cout</tt>, etc. (This implies, for example, that 19080the classical hello, world program may have no output.) In the 19081current draft 19082(<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2798.pdf">N2798</a>), 19083there is a requirement that the objects 19084be constructed before <tt>main</tt>, and before the dynamic 19085initialization of any non-local objects defined after the 19086inclusion of <tt><iostream></tt> in the same translation unit. The only 19087requirement that I can find concerning flushing, however, is in 1908827.5.2.1.6 [ios::Init], where the destructor of the last 19089<tt>std::ios_base::Init</tt> object flushes. But there is, as far as I 19090can see, no guarantee that such an object ever exists. 19091</p> 19092<p> 19093Also, the wording in [iostreams.objects] says that: 19094</p> 19095<blockquote> 19096The objects 19097are constructed and the associations are established at some 19098time prior to or during the first time an object of class 19099<tt>ios_base::Init</tt> is constructed, and in any case before the body 19100of main begins execution. 19101</blockquote> 19102<p> 19103In 27.5.2.1.6 [ios::Init], however, as an 19104effect of the constructor, it says that 19105</p> 19106<blockquote> 19107If <tt>init_cnt</tt> is zero, 19108the function stores the value one in <tt>init_cnt</tt>, then constructs 19109and initializes the objects <tt>cin</tt>, <tt>cout</tt>, <tt>cerr</tt>, <tt>clog</tt> 19110<tt>wcin</tt>, <tt>wcout</tt>, <tt>wcerr</tt>, and <tt>wclog</tt>" 19111</blockquote> 19112 19113<p> 19114which seems to forbid earlier 19115construction. 19116</p> 19117 19118<p> 19119(Note that with these changes, the exposition only "<tt>static 19120int init_cnt</tt>" in <tt>ios_base::Init</tt> can be dropped.) 19121</p> 19122<p> 19123Of course, a determined programmer can still inhibit the 19124flush with things like: 19125</p> 19126<blockquote><pre>new std::ios_base::Init ; // never deleted 19127</pre></blockquote> 19128<p> 19129or (in a function): 19130</p> 19131<blockquote><pre>std::ios_base::Init ensureConstruction ; 19132// ... 19133exit( EXIT_SUCCESS ) ; 19134</pre></blockquote> 19135<p> 19136Perhaps some words somewhere to the effect that all 19137<tt>std::ios_base::Init</tt> objects should have static lifetime 19138would be in order. 19139</p> 19140 19141<p><i>[ 191422009 Santa Cruz: 19143]</i></p> 19144 19145 19146<blockquote> 19147Moved to Ready. Some editorial changes are expected (in addition to the 19148proposed wording) to remove <tt>init_cnt</tt> from <tt>Init</tt>. 19149</blockquote> 19150 19151 19152 19153<p><b>Proposed resolution:</b></p> 19154<p> 19155Change 27.4 [iostream.objects]/2: 19156</p> 19157 19158<blockquote> 19159-2- The objects are constructed and the associations are established at 19160some time prior to or during the first time an object of class 19161<tt>ios_base::Init</tt> is constructed, and in any case before the body 19162of main begins execution.<sup>292</sup> The objects are not destroyed 19163during program execution.<sup>293</sup> 19164<del>If a translation unit includes 19165<tt><iostream></tt> or explicitly constructs an 19166<tt>ios_base::Init</tt> object, these stream objects shall be 19167constructed before dynamic initialization of non-local objects defined 19168later in that translation unit.</del> 19169<ins>The results of including <tt><iostream></tt> in a translation 19170unit shall be as if <tt><iostream></tt> defined an instance of 19171<tt>ios_base::Init</tt> with static lifetime. Similarly, the entire 19172program shall behave as if there were at least one instance of 19173<tt>ios_base::Init</tt> with static lifetime.</ins> 19174</blockquote> 19175 19176<p> 19177Change 27.5.2.1.6 [ios::Init]/3: 19178</p> 19179 19180<blockquote> 19181<pre>Init(); 19182</pre> 19183<blockquote> 19184-3- <i>Effects:</i> Constructs an object of class <tt>Init</tt>. 19185<del>If <tt>init_cnt</tt> is zero, the function stores the value one in 19186<tt>init_cnt</tt>, then constructs and initializes the objects 19187<tt>cin</tt>, <tt>cout</tt>, <tt>cerr</tt>, <tt>clog</tt> (27.4.1), 19188<tt>wcin</tt>, <tt>wcout</tt>, <tt>wcerr</tt>, and <tt>wclog</tt> 19189(27.4.2). In any case, the function then adds one to the value stored in 19190<tt>init_cnt</tt>.</del> 19191<ins>Constructs and initializes the objects <tt>cin</tt>, <tt>cout</tt>, 19192<tt>cerr</tt>, <tt>clog</tt>, <tt>wcin</tt>, <tt>wcout</tt>, 19193<tt>wcerr</tt> and <tt>wclog</tt> if they have not already been 19194constructed and initialized.</ins> 19195</blockquote> 19196</blockquote> 19197 19198<p> 19199Change 27.5.2.1.6 [ios::Init]/4: 19200</p> 19201 19202<blockquote> 19203<pre>~Init(); 19204</pre> 19205<blockquote> 19206-4- <i>Effects:</i> Destroys an object of class <tt>Init</tt>. 19207<del>The function subtracts one from the value stored in <tt>init_cnt</tt> and, 19208if the resulting stored value is one,</del> 19209<ins>If there are no other instances of the class still in 19210existance,</ins> 19211calls <tt>cout.flush()</tt>, 19212<tt>cerr.flush()</tt>, <tt>clog.flush()</tt>, <tt>wcout.flush()</tt>, 19213<tt>wcerr.flush()</tt>, <tt>wclog.flush()</tt>. 19214</blockquote> 19215</blockquote> 19216 19217 19218 19219 19220 19221 19222<hr> 19223<h3><a name="1125"></a>1125. ostream_iterator does not work with movable types</h3> 19224<p><b>Section:</b> 24.6.2.2 [ostream.iterator.ops] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 19225 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-05-28 <b>Last modified:</b> 2009-05-30</p> 19226<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 19227<p><b>Discussion:</b></p> 19228<p> 19229<tt>ostream_iterator</tt> has not been updated to support moveable types, in a 19230similar manner to the insert iterators. 19231Note that this is not a problem for <tt>ostreambuf_iterator</tt>, as the types it is 19232restricted to dealing with do not support extra-efficient moving. 19233</p> 19234 19235 19236<p><b>Proposed resolution:</b></p> 19237<p> 19238Add second <tt>operator=</tt> overload to class <tt>template ostream_iterator</tt> 19239in 24.6.2 [ostream.iterator], para 2: 19240</p> 19241 19242<blockquote><pre>ostream_iterator<T,charT,traits>& operator=(const T& value); 19243<ins>ostream_iterator<T,charT,traits>& operator=(T&& value);</ins> 19244</pre></blockquote> 19245 19246<p> 19247Add a new paragraph: in 24.6.2.2 [ostream.iterator.ops]: 19248</p> 19249 19250<blockquote> 19251<pre>ostream_iterator& operator=(T&& value); 19252</pre> 19253<blockquote> 19254<p> 19255-2- <i>Effects:</i> 19256</p> 19257<blockquote><pre>*out_stream << std::move(value); 19258if(delim != 0) 19259 *out_stream << delim; 19260return (*this); 19261</pre></blockquote> 19262</blockquote> 19263</blockquote> 19264 19265 19266 19267 19268 19269 19270<hr> 19271<h3><a name="1126"></a>1126. <tt>istreambuff_iterator::equal</tt> needs a const & parameter</h3> 19272<p><b>Section:</b> 24.6.3.5 [istreambuf.iterator::equal] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Tentatively Ready</a> 19273 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-05-28 <b>Last modified:</b> 2009-11-02</p> 19274<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#istreambuf.iterator::equal">issues</a> in [istreambuf.iterator::equal].</p> 19275<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20Ready">Tentatively Ready</a> status.</p> 19276<p><b>Discussion:</b></p> 19277<p> 19278The <tt>equal</tt> member function of <tt>istreambuf_iterator</tt> is 19279declared <tt>const</tt>, but takes its argument by non-const reference. 19280</p> 19281<p> 19282This is not compatible with the <tt>operator==</tt> free function overload, which is 19283defined in terms of calling <tt>equal</tt> yet takes both arguments by reference to 19284const. 19285</p> 19286 19287<p><i>[ 19288The proposed wording is consistent with <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#110">110</a> with status TC1. 19289]</i></p> 19290 19291 19292<p><i>[ 192932009-11-02 Howard adds: 19294]</i></p> 19295 19296 19297<blockquote> 19298Set to Tentatively Ready after 5 positive votes on c++std-lib. 19299</blockquote> 19300 19301 19302 19303<p><b>Proposed resolution:</b></p> 19304<p> 19305Ammend in both:<br> 1930624.6.3 [istreambuf.iterator]<br> 1930724.6.3.5 [istreambuf.iterator::equal]<br> 19308</p> 19309 19310<blockquote><pre>bool equal(<ins>const </ins>istreambuf_iterator& b) const; 19311</pre></blockquote> 19312 19313 19314 19315 19316 19317 19318<hr> 19319<h3><a name="1130"></a>1130. <tt>copy_exception</tt> name misleading</h3> 19320<p><b>Section:</b> 18.8.5 [propagation] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Review">Review</a> 19321 <b>Submitter:</b> Peter Dimov <b>Opened:</b> 2009-05-13 <b>Last modified:</b> 2009-10-20</p> 19322<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#propagation">active issues</a> in [propagation].</p> 19323<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#propagation">issues</a> in [propagation].</p> 19324<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Review">Review</a> status.</p> 19325<p><b>Discussion:</b></p> 19326<p> 19327The naming of <tt>std::copy_exception</tt> misleads almost everyone 19328(experts included!) to think that it is the function that copies an 19329<tt>exception_ptr</tt>: 19330</p> 19331 19332<blockquote><pre>exception_ptr p1 = current_exception(); 19333exception_ptr p2 = copy_exception( p1 ); 19334</pre></blockquote> 19335 19336<p> 19337But this is not at all what it does. The above actually creates an 19338<tt>exception_ptr p2</tt> that contains a copy of <tt>p1</tt>, not of 19339the exception to which <tt>p1</tt> refers! 19340</p> 19341<p> 19342This is, of course, all my fault; in my defence, I used <tt>copy_exception</tt> 19343because I was unable to think of a better name. 19344</p> 19345<p> 19346But I believe that, based on what we've seen so far, <em>any</em> other name would be better. 19347</p> 19348<p> 19349Therefore, I propose <tt>copy_exception</tt> to be renamed to 19350<tt>create_exception</tt>: 19351</p> 19352 19353<blockquote><pre>template<class E> exception_ptr create_exception(E e); 19354</pre></blockquote> 19355 19356<p> 19357with the following explanatory paragraph after it: 19358</p> 19359 19360<blockquote> 19361Creates an <tt>exception_ptr</tt> that refers to a copy of <tt>e</tt>. 19362</blockquote> 19363 19364<p><i>[ 193652009-05-13 Daniel adds: 19366]</i></p> 19367 19368 19369<blockquote> 19370<p> 19371What about 19372</p> 19373<blockquote><pre>make_exception_ptr 19374</pre></blockquote> 19375<p> 19376in similarity to <tt>make_pair</tt> and <tt>make_tuple</tt>, <tt>make_error_code</tt> and 19377<tt>make_error_condition</tt>, or <tt>make_shared</tt>? Or, if a stronger symmetry to 19378<tt>current_exception</tt> is preferred: 19379</p> 19380 19381<blockquote><pre>make_exception 19382</pre></blockquote> 19383<p> 19384We have not a single <tt>create_*</tt> function in the library, it was always 19385<tt>make_*</tt> used. 19386</p> 19387</blockquote> 19388 19389<p><i>[ 193902009-05-13 Peter adds: 19391]</i></p> 19392 19393 19394<blockquote> 19395<tt>make_exception_ptr</tt> works for me. 19396</blockquote> 19397 19398<p><i>[ 193992009-06-02 Thomas J. Gritzan adds: 19400]</i></p> 19401 19402 19403<blockquote> 19404<p> 19405To avoid surprises and unwanted recursion, how about making a call to 19406<tt>std::make_exception_ptr</tt> with an <tt>exception_ptr</tt> illegal? 19407</p> 19408<p> 19409It might work like this: 19410</p> 19411<blockquote><pre>template<class E> 19412exception_ptr make_exception_ptr(E e); 19413template<> 19414exception_ptr make_exception_ptr<exception_ptr>(exception_ptr e) = delete; 19415</pre></blockquote> 19416</blockquote> 19417 19418<p><i>[ 194192009 Santa Cruz: 19420]</i></p> 19421 19422 19423<blockquote> 19424Move to Review for the time being. The subgroup thinks this is a good 19425idea, but doesn't want to break compatibility unnecessarily if someone 19426is already shipping this. Let's talk to Benjamin and PJP tomorrow to 19427make sure neither objects. 19428</blockquote> 19429 19430 19431 19432<p><b>Proposed resolution:</b></p> 19433<p> 19434Change 18.8.5 [propagation]: 19435</p> 19436 19437<blockquote> 19438<pre>template<class E> exception_ptr <del>copy_exception</del><ins>make_exception_ptr</ins>(E e); 19439</pre> 19440 19441<blockquote> 19442<p> 19443-11- <i>Effects:</i> <ins>Creates an <tt>exception_ptr</tt> that refers 19444to a copy of <tt>e</tt>,</ins> as if 19445</p> 19446 19447<blockquote><pre>try { 19448 throw e; 19449} catch(...) { 19450 return current_exception(); 19451} 19452</pre></blockquote> 19453 19454<p>...</p> 19455</blockquote> 19456 19457</blockquote> 19458 19459 19460 19461 19462 19463 19464<hr> 19465<h3><a name="1131"></a>1131. C++0x does not need <tt>alignment_of</tt></h3> 19466<p><b>Section:</b> 20.6.4.3 [meta.unary.prop] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 19467 <b>Submitter:</b> Niels Dekker <b>Opened:</b> 2009-06-01 <b>Last modified:</b> 2009-06-02</p> 19468<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#meta.unary.prop">active issues</a> in [meta.unary.prop].</p> 19469<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#meta.unary.prop">issues</a> in [meta.unary.prop].</p> 19470<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 19471<p><b>Discussion:</b></p> 19472<p> 19473The <tt>alignment_of</tt> template is no longer necessary, now that the 19474core language will provide <tt>alignof</tt>. Scott Meyers raised this 19475issue at comp.std.c++, 19476<a href="http://groups.google.com/group/comp.std.c++/browse_thread/thread/9b020306e803f08a">C++0x: alignof vs. alignment_of</a>, 19477May 21, 2009. In a reply, Daniel Kr�gler pointed out that 19478<tt>alignof</tt> was added to the working paper <i>after</i> 19479<tt>alignment_of</tt>. So it appears that <tt>alignment_of</tt> is only 19480part of the current Working Draft 19481(<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2857.pdf">N2857</a>) 19482because it is in TR1. 19483</p> 19484<p> 19485Having both <tt>alignof</tt> and <tt>alignment_of</tt> would cause 19486unwanted confusion. In general, I think TR1 functionality should not be 19487brought into C++0x if it is entirely redundant with other C++0x language 19488or library features. 19489</p> 19490 19491 19492<p><b>Proposed resolution:</b></p> 19493<p> 19494Remove from Header <type_traits> synopsis 20.6.2 [meta.type.synop]: 19495</p> 19496<blockquote><pre><del>template <class T> struct alignment_of;</del> 19497</pre></blockquote> 19498 19499<p> 19500Remove the first row of Table 34 ("Type property queries"), from 19501Type properties 20.6.4.3 [meta.unary.prop]: 19502</p> 19503<blockquote> 19504<table border="1"> 19505<caption>Table 34 -- Type property queries</caption> 19506<tbody><tr> 19507<td><del><tt>template <class T> struct alignment_of;</tt></del></td> 19508<td><del><tt>alignof(T)</tt>.</del><br> 19509<del><i>Precondition:</i> <tt>T</tt> shall be a complete type, a reference 19510type, or an array of unknown bound, but shall not be a function type or 19511(possibly cv-qualified) <tt>void</tt>.</del> 19512</td> 19513</tr> 19514</tbody></table> 19515</blockquote> 19516 19517<p> 19518Change text in Table 41 ("Other transformations"), from Other 19519transformations 20.6.7 [meta.trans.other], as follows: 19520</p> 19521<blockquote> 19522<table border="1"> 19523<caption>Table 41 -- Other transformations</caption> 19524<tbody><tr><td>...</td> 19525<td> 19526 Align shall be equal to <tt> 19527 <del>alignment_of<T>::value</del> 19528 <ins>alignof(T)</ins> 19529 </tt> for some type <tt>T</tt> or to <i>default-alignment</i>. 19530</td> 19531<td>...</td> 19532</tr></tbody></table> 19533</blockquote> 19534 19535 19536 19537 19538 19539<hr> 19540<h3><a name="1133"></a>1133. Does N2844 break current specification of list::splice?</h3> 19541<p><b>Section:</b> 23.3.3.5 [forwardlist.ops], 23.3.4.4 [list.ops] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 19542 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-05-09 <b>Last modified:</b> 2009-10-27</p> 19543<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#forwardlist.ops">issues</a> in [forwardlist.ops].</p> 19544<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 19545<p><b>Discussion:</b></p> 19546<p> 19547IIUC, 19548<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2844.html">N2844</a> 19549means that lvalues will no longer bind to rvalue references. 19550Therefore, the current specification of <tt>list::splice</tt> (list 19551operations 23.3.4.4 [list.ops]) will be a breaking change of behaviour for existing 19552programs. That is because we changed the signature to swallow via an rvalue 19553reference rather than the lvalue reference used in 03. 19554</p> 19555<p> 19556Retaining this form would be safer, requiring an explicit move when splicing 19557from lvalues. However, this will break existing programs. 19558We have the same problem with <tt>forward_list</tt>, although without the risk of 19559breaking programs so here it might be viewed as a positive feature. 19560</p> 19561<p> 19562The problem signatures: 19563</p> 19564<blockquote><pre>void splice_after(const_iterator position, forward_list<T,Alloc>&& x); 19565void splice_after(const_iterator position, forward_list<T,Alloc>&& x, 19566 const_iterator i); 19567void splice_after(const_iterator position, forward_list<T,Alloc>&& x, 19568 const_iterator first, const_iterator last); 19569 19570void splice(const_iterator position, list<T,Alloc>&& x); 19571void splice(const_iterator position, list<T,Alloc>&& x, 19572 const_iterator i); 19573void splice(const_iterator position, list<T,Alloc>&& x, 19574 const_iterator first, const_iterator last); 19575</pre></blockquote> 19576 19577<b>Possible resolutions:</b> 19578 19579<p> 19580Option A. Add an additional (non-const) lvalue-reference 19581overload in each case 19582</p> 19583<p> 19584Option B. Change rvalue reference back to (non-const) 19585lvalue-reference overload in each case 19586</p> 19587<p> 19588Option C. Add an additional (non-const) lvalue-reference 19589overload in just the <tt>std::list</tt> cases 19590</p> 19591<p> 19592I think (B) would be very unfortunate, I really like the <tt>forward_list</tt> 19593behaviour in (C) but feel (A) is needed for consistency. 19594</p> 19595<p> 19596My actual preference would be NAD, ship with this as a breaking change as it 19597is a more explicit interface. I don't think that will fly though! 19598</p> 19599 19600<p> 19601See the thread starting with c++std-lib-23725 for more discussion. 19602</p> 19603 19604<p><i>[ 196052009-10-27 Christopher Jefferson provides proposed wording for Option C. 19606]</i></p> 19607 19608 19609 19610<p><b>Proposed resolution:</b></p> 19611<p> 19612In 23.3.4 [list] 19613</p> 19614 19615<p> 19616Add lvalue overloads before rvalue ones: 19617</p> 19618 19619<blockquote><pre><ins>void splice(const_iterator position, list<T,Allocator>& x);</ins> 19620void splice(const_iterator position, list<T,Allocator>&& x); 19621<ins>void splice(const_iterator position, list<T,Allocator>& x, const_iterator i);</ins> 19622void splice(const_iterator position, list<T,Allocator>&& x, const_iterator i); 19623<ins>void splice(const_iterator position, list<T,Allocator>& x, 19624 const_iterator first, const_iterator last);</ins> 19625void splice(const_iterator position, list<T,Allocator>&& x, 19626 const_iterator first, const_iterator last); 19627</pre></blockquote> 19628 19629<p> 19630In 23.3.4.4 [list.ops], similarly add lvalue overload before each rvalue one: 19631</p> 19632<p> 19633(After paragraph 2) 19634</p> 19635 19636<blockquote><pre><ins>void splice(const_iterator position, list<T,Allocator>& x);</ins> 19637void splice(const_iterator position, list<T,Allocator>&& x); 19638</pre></blockquote> 19639 19640<p> 19641(After paragraph 6) 19642</p> 19643 19644<blockquote><pre><ins>void splice(const_iterator position, list<T,Allocator>& x, const_iterator i);</ins> 19645void splice(const_iterator position, list<T,Allocator>&& x, const_iterator i); 19646</pre></blockquote> 19647 19648<p> 19649(After paragraph 10) 19650</p> 19651 19652<blockquote><pre><ins>void splice(const_iterator position, list<T,Allocator>& x, 19653 const_iterator first, const_iterator last);</ins> 19654void splice(const_iterator position, list<T,Allocator>&& x, 19655 const_iterator first, const_iterator last); 19656</pre></blockquote> 19657 19658 19659 19660 19661 19662 19663<hr> 19664<h3><a name="1134"></a>1134. Redundant specification of stdint.h, fenv.h, tgmath.h, and maybe complex.h</h3> 19665<p><b>Section:</b> 18.4.2 [stdinth], 26.3.2 [fenv], 26.8 [c.math], 26.4.11 [cmplxh] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 19666 <b>Submitter:</b> Robert Klarer <b>Opened:</b> 2009-05-26 <b>Last modified:</b> 2009-10-20</p> 19667<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 19668<p><b>Discussion:</b></p> 19669<p> 19670This is probably editorial. 19671</p> 19672<p> 19673The following items should be removed from the draft, because they're 19674redundant with Annex D, and they arguably make some *.h headers 19675non-deprecated: 19676</p> 19677<p> 1967818.4.2 [stdinth] (regarding <tt><stdint.h></tt>) 19679</p> 19680<p> 1968126.3.2 [fenv] (regarding <tt><fenv.h></tt> 19682</p> 19683<p> 19684Line 3 of 26.8 [c.math] (regarding <tt><tgmath.h></tt>) 19685</p> 19686<p> 1968726.4.11 [cmplxh] (regarding <tt><complex.h></tt>, though the note in this subclause is not redundant) 19688</p> 19689 19690<p><i>[ 196912009-06-10 Ganesh adds: 19692]</i></p> 19693 19694 19695<blockquote> 19696While searching for <tt>stdint</tt> in the CD, I found that <tt><stdint.h></tt> is also 19697mentioned in 3.9.1 [basic.fundamental] /5. It guess it should refer to 19698<tt><cstdint></tt> instead. 19699</blockquote> 19700 19701<p><i>[ 197022009 Santa Cruz: 19703]</i></p> 19704 19705 19706<blockquote> 19707Real issue. Maybe just editorial, maybe not. Move to Ready. 19708</blockquote> 19709 19710 19711 19712<p><b>Proposed resolution:</b></p> 19713<p> 19714Remove the section 18.4.2 [stdinth]. 19715</p> 19716<p> 19717Remove the section 26.3.2 [fenv]. 19718</p> 19719<p> 19720Remove 26.8 [c.math], p3: 19721</p> 19722 19723<blockquote> 19724<del>-3- The header <tt><tgmath.h></tt> effectively includes the headers <tt><complex.h></tt> 19725and <tt><math.h></tt>.</del> 19726</blockquote> 19727<p> 19728Remove the section 26.4.11 [cmplxh]. 19729</p> 19730 19731 19732 19733 19734 19735<hr> 19736<h3><a name="1135"></a>1135. <tt>exception_ptr</tt> should support contextual conversion to <tt>bool</tt></h3> 19737<p><b>Section:</b> 18.8.5 [propagation] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 19738 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2007-06-06 <b>Last modified:</b> 2009-10-20</p> 19739<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#propagation">active issues</a> in [propagation].</p> 19740<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#propagation">issues</a> in [propagation].</p> 19741<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 19742<p><b>Discussion:</b></p> 19743<p> 19744As of 19745<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2857.pdf">N2857</a> 1974618.8.5 [propagation]/5, the implementation-defined type 19747<tt>exception_ptr</tt> does provide the following ways to check whether 19748it is a null value: 19749</p> 19750<blockquote><pre>void f(std::exception_ptr p) { 19751 p == nullptr; 19752 p == 0; 19753 p == exception_ptr(); 19754} 19755</pre></blockquote> 19756<p> 19757This is rather cumbersome way of checking for the null value 19758and I suggest to require support for evaluation in a boolean 19759context like so: 19760</p> 19761 19762<blockquote><pre>void g(std::exception_ptr p) { 19763 if (p) {} 19764 !p; 19765} 19766</pre></blockquote> 19767 19768<p><i>[ 197692009 Santa Cruz: 19770]</i></p> 19771 19772 19773<blockquote> 19774Move to Ready. Note to editor: considering putting in a cross-reference 19775to 4 [conv], paragraph 3, which defines the phrase 19776"contextually converted to <tt>bool</tt>". 19777</blockquote> 19778 19779 19780 19781<p><b>Proposed resolution:</b></p> 19782<p> 19783In section 18.8.5 [propagation] insert a new paragraph between p.5 and p.6: 19784</p> 19785 19786<blockquote> 19787<ins> 19788An object <tt>e</tt> of type <tt>exception_ptr</tt> can be contextually converted to <tt>bool</tt>. 19789The effect shall be as if <tt>e != exception_ptr()</tt> had been evaluated in place 19790of <tt>e</tt>. There shall be no implicit conversion to arithmetic type, to 19791enumeration type or to pointer type. 19792</ins> 19793</blockquote> 19794 19795 19796 19797 19798 19799<hr> 19800<h3><a name="1136"></a>1136. Incomplete specification of <tt>nested_exception::rethrow_nested()</tt></h3> 19801<p><b>Section:</b> 18.8.6 [except.nested] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 19802 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2007-06-06 <b>Last modified:</b> 2009-10-20</p> 19803<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#except.nested">active issues</a> in [except.nested].</p> 19804<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#except.nested">issues</a> in [except.nested].</p> 19805<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 19806<p><b>Discussion:</b></p> 19807<p> 19808It was recently mentioned in a newsgroup article 19809<a href="http://groups.google.de/group/comp.std.c++/msg/f82022aff68edf3d">http://groups.google.de/group/comp.std.c++/msg/f82022aff68edf3d</a> 19810that the specification of the member function <tt>rethrow_nested()</tt> of the 19811class <tt>nested_exception</tt> is incomplete, specifically it remains unclear 19812what happens, if member <tt>nested_ptr()</tt> returns a null value. In 1981318.8.6 [except.nested] we find only the following paragraph related to that: 19814</p> 19815<blockquote><pre>void rethrow_nested() const; // [[noreturn]] 19816</pre> 19817<blockquote> 19818-4- <i>Throws:</i> the stored exception captured by this <tt>nested_exception</tt> object. 19819</blockquote> 19820</blockquote> 19821<p> 19822This is a problem, because it is possible to create an object of 19823<tt>nested_exception</tt> with exactly such a state, e.g. 19824</p> 19825<blockquote><pre>#include <exception> 19826#include <iostream> 19827 19828int main() try { 19829 std::nested_exception e; // OK, calls current_exception() and stores it's null value 19830 e.rethrow_nested(); // ? 19831 std::cout << "A" << std::endl; 19832} 19833catch(...) { 19834 std::cout << "B" << std::endl; 19835} 19836</pre></blockquote> 19837<p> 19838I suggest to follow the proposal of the reporter, namely to invoke 19839<tt>terminate()</tt> if <tt>nested_ptr()</tt> return a null value of <tt>exception_ptr</tt> instead 19840of relying on the fallback position of undefined behavior. This would 19841be consistent to the behavior of a <tt>throw;</tt> statement when no 19842exception is being handled. 19843</p> 19844 19845<p><i>[ 198462009 Santa Cruz: 19847]</i></p> 19848 19849 19850<blockquote> 19851Move to Ready. 19852</blockquote> 19853 19854 19855 19856<p><b>Proposed resolution:</b></p> 19857<p> 19858Change around 18.8.6 [except.nested]/4 as indicated: 19859</p> 19860<blockquote> 19861<p> 19862-4- <i>Throws:</i> the stored exception captured by this <tt>nested_exception</tt> 19863object<ins>, if <tt>nested_ptr() != nullptr</tt></ins> 19864</p> 19865<p> 19866<ins>- <i>Remarks:</i> If <tt>nested_ptr() == nullptr</tt>, <tt>terminate()</tt> 19867shall be called.</ins> 19868</p> 19869</blockquote> 19870 19871 19872 19873 19874 19875<hr> 19876<h3><a name="1137"></a>1137. Return type of <tt>conj</tt> and <tt>proj</tt></h3> 19877<p><b>Section:</b> 26.4.9 [cmplx.over] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 19878 <b>Submitter:</b> Marc Steinbach <b>Opened:</b> 2009-06-11 <b>Last modified:</b> 2009-06-27</p> 19879<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#cmplx.over">issues</a> in [cmplx.over].</p> 19880<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 19881<p><b>Discussion:</b></p> 19882<p> 19883In clause 1, the Working Draft 19884(<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2857.pdf">N2857</a>) 19885specifies overloads of the 19886functions 19887</p> 19888<blockquote><pre>arg, conj, imag, norm, proj, real 19889</pre></blockquote> 19890<p> 19891for non-complex arithmetic types (<tt>float</tt>, <tt>double</tt>, 19892<tt>long double</tt>, and integers). 19893The only requirement (clause 2) specifies effective type promotion of arguments. 19894</p> 19895<p> 19896I strongly suggest to add the following requirement on the return types: 19897</p> 19898<blockquote> 19899All the specified overloads must return real (i.e., non-complex) values, 19900specifically, the nested <tt>value_type</tt> of effectively promoted arguments. 19901</blockquote> 19902 19903<p> 19904(This has no effect on <tt>arg</tt>, <tt>imag</tt>, <tt>norm</tt>, <tt>real</tt>: 19905they are real-valued anyway.) 19906</p> 19907<p><b>Rationale:</b></p> 19908<p> 19909Mathematically, <tt>conj()</tt> and <tt>proj()</tt>, like the transcendental functions, are 19910complex-valued in general but map the (extended) real line to itself. 19911In fact, both functions act as identity on the reals. 19912A typical user will expect <tt>conj()</tt> and <tt>proj()</tt> to preserve this essential 19913mathematical property in the same way as <tt>exp()</tt>, <tt>sin()</tt>, etc. 19914A typical use of <tt>conj()</tt>, e.g., is the generic scalar product of n-vectors: 19915</p> 19916 19917<blockquote><pre>template<typename T> 19918inline T 19919scalar_product(size_t n, T const* x, T const* y) { 19920 T result = 0; 19921 for (size_t i = 0; i < n; ++i) 19922 result += x[i] * std::conj(y[i]); 19923 return result; 19924} 19925</pre></blockquote> 19926<p> 19927This will work equally well for real and complex floating-point types <tt>T</tt> if 19928<tt>conj()</tt> returns <tt>T</tt>. It will not work with real types if <tt>conj()</tt> 19929returns complex values. 19930</p> 19931<p> 19932Instead, the implementation of <tt>scalar_product</tt> becomes either less efficient 19933and less useful (if a complex result is always returned), or unnecessarily 19934complicated (if overloaded versions with proper return types are defined). 19935In the second case, the real-argument overload of <tt>conj()</tt> cannot be used. 19936In fact, it must be avoided. 19937</p> 19938<p> 19939Overloaded <tt>conj()</tt> and <tt>proj()</tt> are principally needed in generic programming. 19940All such use cases will benefit from the proposed return type requirement, 19941in a similar way as the <tt>scalar_product</tt> example. 19942The requirement will not harm use cases where a complex return value 19943is expected, because of implicit conversion to complex. 19944Without the proposed return type guarantee, I find overloaded versions 19945of <tt>conj()</tt> and <tt>proj()</tt> not only useless but actually troublesome. 19946</p> 19947 19948 19949 19950<p><b>Proposed resolution:</b></p> 19951<p> 19952Insert a new paragraph after 26.4.9 [cmplx.over]/2: 19953</p> 19954 19955<blockquote> 19956<ins> 19957All of the specified overloads shall have a return type which is the nested <tt>value_type</tt> of 19958the effectively promoted arguments. 19959</ins> 19960</blockquote> 19961 19962 19963 19964 19965 19966<hr> 19967<h3><a name="1138"></a>1138. unusual return value for operator+</h3> 19968<p><b>Section:</b> 21.4.8.1 [string::op+] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Tentatively Ready</a> 19969 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-06-12 <b>Last modified:</b> 2009-11-05</p> 19970<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20Ready">Tentatively Ready</a> status.</p> 19971<p><b>Discussion:</b></p> 19972<p> 19973Many of the <tt>basic_string operator+</tt> overloads return an rvalue-reference. Is 19974that really intended? 19975</p> 19976<p> 19977I'm considering it might be a mild performance tweak to avoid making 19978un-necessary copies of a cheaply movable type, but it opens risk to dangling 19979references in code like: 19980</p> 19981 19982<blockquote><pre>auto && s = string{"x"} + string{y}; 19983</pre></blockquote> 19984 19985<p> 19986and I'm not sure about: 19987</p> 19988 19989<blockquote><pre>auto s = string{"x"} + string{y}; 19990</pre></blockquote> 19991 19992<p><i>[ 199932009-10-11 Howard updated <i>Returns:</i> clause for each of these. 19994]</i></p> 19995 19996 19997<p><i>[ 199982009-11-05 Howard adds: 19999]</i></p> 20000 20001 20002<blockquote> 20003Moved to Tentatively Ready after 5 positive votes on c++std-lib. 20004</blockquote> 20005 20006 20007<p><b>Proposed resolution:</b></p> 20008<p> 20009Strike the <tt>&&</tt> from the return type in the following function 20010signatures: 20011</p> 20012 20013<blockquote> 20014<p> 2001521.3 [string.classes] p2 Header Synopsis 20016</p> 20017 20018<blockquote><pre>template<class charT, class traits, class Allocator> 20019 basic_string<charT,traits,Allocator><del>&&</del> 20020 operator+(basic_string<charT,traits,Allocator>&& lhs, 20021 const basic_string<charT,traits,Allocator>& rhs); 20022 20023template<class charT, class traits, class Allocator> 20024 basic_string<charT,traits,Allocator><del>&&</del> 20025 operator+(const basic_string<charT,traits,Allocator>& lhs, 20026 basic_string<charT,traits,Allocator>&& rhs); 20027 20028template<class charT, class traits, class Allocator> 20029 basic_string<charT,traits,Allocator><del>&&</del> 20030 operator+(basic_string<charT,traits,Allocator>&& lhs, 20031 basic_string<charT,traits,Allocator>&& rhs); 20032 20033 20034template<class charT, class traits, class Allocator> 20035 basic_string<charT,traits,Allocator><del>&&</del> 20036 operator+(const charT* lhs, 20037 basic_string<charT,traits,Allocator>&& rhs); 20038 20039template<class charT, class traits, class Allocator> 20040 basic_string<charT,traits,Allocator><del>&&</del> 20041 operator+(charT lhs, basic_string<charT,traits,Allocator>&& rhs); 20042 20043template<class charT, class traits, class Allocator> 20044 basic_string<charT,traits,Allocator><del>&&</del> 20045 operator+(basic_string<charT,traits,Allocator>&& lhs, 20046 const charT* rhs); 20047 20048template<class charT, class traits, class Allocator> 20049 basic_string<charT,traits,Allocator><del>&&</del> 20050 operator+(basic_string<charT,traits,Allocator>&& lhs, charT rhs); 20051</pre></blockquote> 20052 20053<p> 2005421.4.8.1 [string::op+] 20055</p> 20056 20057<blockquote><pre>template<class charT, class traits, class Allocator> 20058 basic_string<charT,traits,Allocator><del>&&</del> 20059 operator+(basic_string<charT,traits,Allocator>&& lhs, 20060 const basic_string<charT,traits,Allocator>& rhs); 20061</pre> 20062<blockquote> 20063<i>Returns:</i> <tt><ins>std::move(</ins>lhs.append(rhs)<ins>)</ins></tt> 20064</blockquote> 20065<pre>template<class charT, class traits, class Allocator> 20066 basic_string<charT,traits,Allocator><del>&&</del> 20067 operator+(const basic_string<charT,traits,Allocator>& lhs, 20068 basic_string<charT,traits,Allocator>&& rhs); 20069</pre> 20070<blockquote> 20071<i>Returns:</i> <tt><ins>std::move(</ins>rhs.insert(0, lhs)<ins>)</ins></tt> 20072</blockquote> 20073<pre>template<class charT, class traits, class Allocator> 20074 basic_string<charT,traits,Allocator><del>&&</del> 20075 operator+(basic_string<charT,traits,Allocator>&& lhs, 20076 basic_string<charT,traits,Allocator>&& rhs); 20077</pre> 20078<blockquote> 20079<i>Returns:</i> <tt><ins>std::move(</ins>lhs.append(rhs)<ins>)</ins></tt> [<i>Note:</i> Or equivalently 20080<tt><ins>std::move(</ins>rhs.insert(0, lhs)<ins>)</ins></tt> — <i>end note</i>] 20081</blockquote> 20082<pre>template<class charT, class traits, class Allocator> 20083 basic_string<charT,traits,Allocator><del>&&</del> 20084 operator+(const charT* lhs, 20085 basic_string<charT,traits,Allocator>&& rhs); 20086</pre> 20087<blockquote> 20088<i>Returns:</i> <tt><ins>std::move(</ins>rhs.insert(0, lhs)<ins>)</ins></tt>. 20089</blockquote> 20090<pre>template<class charT, class traits, class Allocator> 20091 basic_string<charT,traits,Allocator><del>&&</del> 20092 operator+(charT lhs, basic_string<charT,traits,Allocator>&& rhs); 20093</pre> 20094<blockquote> 20095<i>Returns:</i> <tt><ins>std::move(</ins>rhs.insert(0, 1, lhs)<ins>)</ins></tt>. 20096</blockquote> 20097<pre>template<class charT, class traits, class Allocator> 20098 basic_string<charT,traits,Allocator><del>&&</del> 20099 operator+(basic_string<charT,traits,Allocator>&& lhs, 20100 const charT* rhs); 20101</pre> 20102<blockquote> 20103<i>Returns:</i> <tt><ins>std::move(</ins>lhs.append(rhs)<ins>)</ins></tt>. 20104</blockquote> 20105<pre>template<class charT, class traits, class Allocator> 20106 basic_string<charT,traits,Allocator><del>&&</del> 20107 operator+(basic_string<charT,traits,Allocator>&& lhs, charT rhs); 20108</pre> 20109<blockquote> 20110<i>Returns:</i> <tt><ins>std::move(</ins>lhs.append(1, rhs)<ins>)</ins></tt>. 20111</blockquote> 20112</blockquote> 20113 20114</blockquote> 20115 20116 20117 20118 20119 20120 20121<hr> 20122<h3><a name="1144"></a>1144. "thread safe" is undefined</h3> 20123<p><b>Section:</b> 18.5 [support.start.term] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 20124 <b>Submitter:</b> LWG <b>Opened:</b> 2009-06-16 <b>Last modified:</b> 2009-10-20</p> 20125<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#support.start.term">issues</a> in [support.start.term].</p> 20126<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 20127<p><b>Discussion:</b></p> 20128 20129<p><b>Addresses UK 187</b></p> 20130 20131<p> 20132The term "thread safe" is not defined nor used in this context 20133anywhere else in the standard. 20134</p> 20135 20136<p><b>Suggested action:</b></p> 20137<p> 20138Clarify the meaning of "thread safe". 20139</p> 20140 20141<p><i>[ 201422009 Santa Cruz: 20143]</i></p> 20144 20145 20146<blockquote> 20147<p> 20148The "thread safe" language has already been change in the WP. It was 20149changed to "happen before", but the current WP text is still a little 20150incomplete: "happen before" is binary, but the current WP text only 20151mentions one thing. 20152</p> 20153<p> 20154Move to Ready. 20155</p> 20156</blockquote> 20157 20158 20159 20160<p><b>Proposed resolution:</b></p> 20161<p> 20162For the following functions in 18.5 [support.start.term]. 20163</p> 20164<blockquote><pre><code> 20165extern "C" int at_quick_exit(void (*f)(void)); 20166extern "C++" int at_quick_exit(void (*f)(void)); 20167</code></pre></blockquote> 20168 20169<p> 20170Edit paragraph 10 as follows. 20171The intent is 20172to provide the other half of the happens before relation; 20173to note indeterminate ordering; 20174and to clean up some formatting. 20175</p> 20176<blockquote><p> 20177<i>Effects:</i> 20178The <code>at_quick_exit()</code> functions 20179register the function pointed to by <code>f</code> 20180to be called without arguments when <code>quick_exit</code> is called. 20181It is unspecified whether a call to <code>at_quick_exit()</code> 20182that does not <del>happen-before</del> <ins>happen before</ins> (1.10) 20183<ins>all calls to <code>quick_exit</code></ins> 20184will succeed. 20185[<i>Note:</i> 20186the <code>at_quick_exit()</code> functions 20187shall not introduce a data race (17.6.4.7). 20188<del>exitnote</del> 20189<ins>—<i>end note</i>]</ins> 20190<ins> 20191[<i>Note:</i> 20192The order of registration may be indeterminate 20193if <code>at_quick_exit</code> was called from more than one thread. 20194—<i>end note</i>] 20195</ins> 20196[<i>Note:</i> The <code>at_quick_exit</code> registrations 20197are distinct from the <code>atexit</code> registrations, 20198and applications may need to call both registration functions 20199with the same argument. 20200—<i>end note</i>] 20201</p></blockquote> 20202 20203<p> 20204For the following function. 20205</p> 20206<blockquote><pre><code> 20207void quick_exit [[noreturn]] (int status) 20208</code></pre></blockquote> 20209 20210<p> 20211Edit paragraph 13 as follows. 20212The intent is to note that thread-local variables may be different. 20213</p> 20214<blockquote><p> 20215<i>Effects:</i> 20216Functions registered by calls to <code>at_quick_exit</code> 20217are called in the reverse order of their registration, 20218except that a function shall be called 20219after any previously registered functions 20220that had already been called at the time it was registered. 20221Objects shall not be destroyed as a result of calling <code>quick_exit</code>. 20222If control leaves a registered function called by <code>quick_exit</code> 20223because the function does not provide a handler for a thrown exception, 20224<code>terminate()</code> shall be called. 20225<ins> 20226[<i>Note:</i> 20227Functions registered by one thread may be called by any thread, 20228and hence should not rely on the identity of thread-storage-duration objects. 20229—<i>end note</i>] 20230</ins> 20231After calling registered functions, 20232<code>quick_exit</code> shall call <code>_Exit(status)</code>. 20233[<i>Note:</i> 20234The standard file buffers are not flushed. 20235See: ISO C 7.20.4.4. 20236—<i>end note</i>] 20237</p></blockquote> 20238 20239 20240 20241 20242 20243<hr> 20244<h3><a name="1151"></a>1151. Behavior of the library in the presence of threads is incompletely specified</h3> 20245<p><b>Section:</b> 17 [library] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 20246 <b>Submitter:</b> LWG <b>Opened:</b> 2009-06-28 <b>Last modified:</b> 2009-10-20</p> 20247<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#library">active issues</a> in [library].</p> 20248<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#library">issues</a> in [library].</p> 20249<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 20250<p><b>Discussion:</b></p> 20251<p><b>Addresses US 63</b></p> 20252 20253 <p><b>Description</b></p> 20254 <p>The behavior of the library in the presence of threads 20255 is incompletely specified.</p> 20256 <p>For example, if thread 1 assigns to <tt>X</tt>, then writes data 20257 to file <tt>f</tt>, which is read by thread 2, and then accesses 20258 variable <tt>X</tt>, is thread 2 guaranteed to be able to see the 20259 value assigned to <tt>X</tt> by thread 1? In other words, does the 20260 write of the data "happen before" the read?</p> 20261 <p>Another example: does simultaneous access using <tt>operator 20262 at()</tt> to different characters in the same non-const string 20263 really introduce a data race?</p> 20264<p><b>Suggestion</b></p> 20265<p><b>Notes</b></p><p>17 SG: should go to threads group; misclassified in document 20266</p> 20267 20268 <p>Concurrency SG: Create an issue. Hans will look into it.</p> 20269 20270<p><i>[ 202712009 Santa Cruz: 20272]</i></p> 20273 20274 20275<blockquote> 20276Move to "Open". Hans and the rest of the concurrency working group will 20277study this. We can't make progress without a thorough review and a 20278paper. 20279</blockquote> 20280 20281 20282 20283<p><b>Proposed resolution:</b></p> 20284 20285 20286 20287 20288 20289<hr> 20290<h3><a name="1152"></a>1152. expressions parsed differently than intended</h3> 20291<p><b>Section:</b> 22.4.2.2.2 [facet.num.put.virtuals] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Tentatively Ready</a> 20292 <b>Submitter:</b> Seungbeom Kim <b>Opened:</b> 2009-06-27 <b>Last modified:</b> 2009-10-28</p> 20293<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#facet.num.put.virtuals">active issues</a> in [facet.num.put.virtuals].</p> 20294<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#facet.num.put.virtuals">issues</a> in [facet.num.put.virtuals].</p> 20295<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20Ready">Tentatively Ready</a> status.</p> 20296<p><b>Discussion:</b></p> 20297<p> 20298In Table 73 -- Floating-point conversions, 22.4.2.2.2 [facet.num.put.virtuals], 20299in 20300<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2914.pdf">N2914</a>, 20301we have the following entries: 20302</p> 20303<table border="1"> 20304<caption>Table 73 — Floating-point conversions</caption> 20305<tbody><tr> 20306<th>State</th> <th><tt>stdio</tt> equivalent</th> 20307</tr> 20308<tr> 20309<td><tt>floatfield == ios_base::fixed | ios_base::scientific && !uppercase</tt></td> 20310<td align="center"><tt>%a</tt></td> 20311</tr> 20312 20313<tr> 20314<td><tt>floatfield == ios_base::fixed | ios_base::scientific</tt></td> 20315<td align="center"><tt>%A</tt></td> 20316</tr> 20317</tbody></table> 20318 20319<p> 20320These expressions are supposed to mean: 20321</p> 20322 20323<blockquote><pre>floatfield == (ios_base::fixed | ios_base::scientific) && !uppercase 20324floatfield == (ios_base::fixed | ios_base::scientific) 20325</pre></blockquote> 20326<p> 20327but technically parsed as: 20328</p> 20329<blockquote><pre>((floatfield == ios_base::fixed) | ios_base::scientific) && (!uppercase) 20330((floatfield == ios_base::fixed) | ios_base::scientific) 20331</pre></blockquote> 20332<p> 20333and should be corrected with additional parentheses, as shown above. 20334</p> 20335 20336<p><i>[ 203372009-10-28 Howard: 20338]</i></p> 20339 20340 20341<blockquote> 20342Moved to Tentatively Ready after 5 positive votes on c++std-lib. 20343</blockquote> 20344 20345 20346 20347<p><b>Proposed resolution:</b></p> 20348<p> 20349Change Table 83 — Floating-point conversions in 22.4.2.2.2 [facet.num.put.virtuals]: 20350</p> 20351 20352<table border="1"> 20353<caption>Table 83 — Floating-point conversions</caption> 20354<tbody><tr> 20355<th>State</th> <th><tt>stdio</tt> equivalent</th> 20356</tr> 20357<tr> 20358<td><tt>floatfield == <ins>(</ins>ios_base::fixed | ios_base::scientific<ins>)</ins> && !uppercase</tt></td> 20359<td align="center"><tt>%a</tt></td> 20360</tr> 20361 20362<tr> 20363<td><tt>floatfield == <ins>(</ins>ios_base::fixed | ios_base::scientific<ins>)</ins></tt></td> 20364<td align="center"><tt>%A</tt></td> 20365</tr> 20366</tbody></table> 20367 20368 20369 20370 20371 20372<hr> 20373<h3><a name="1153"></a>1153. Standard library needs review for constructors to be 20374explicit to avoid treatment as initializer-list constructor</h3> 20375<p><b>Section:</b> 17 [library], 30 [thread], D [depr] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 20376 <b>Submitter:</b> LWG <b>Opened:</b> 2009-06-28 <b>Last modified:</b> 2009-10-20</p> 20377<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#library">active issues</a> in [library].</p> 20378<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#library">issues</a> in [library].</p> 20379<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 20380<p><b>Discussion:</b></p> 20381 20382<p><b>Addresses DE 2</b></p> 20383 20384<p><b>Description</b></p> 20385 <p>Marking a constructor with <tt>explicit</tt> has semantics 20386 even for a constructor with zero or several parameters: 20387 Such a constructor cannot be used with list-initialization 20388 in a copy-initialization context, see 13.3.1.7 [over.match.list]. The 20389 standard library apparently has not been reviewed for 20390 marking non-single-parameter constructors as <tt>explicit</tt>.</p> 20391<p><b>Suggestion</b></p> 20392 <p>Consider marking zero-parameter and multi-parameter 20393 constructors <tt>explicit</tt> in classes that have at least one 20394 constructor marked <tt>explicit</tt> and that do not have an 20395 initializer-list constructor.</p> 20396 20397<p><b>Notes</b></p> 20398 <p>Robert Klarer to address this one.</p> 20399 20400<p><i>[ 204012009 Santa Cruz: 20402]</i></p> 20403 20404 20405<blockquote> 20406Move to "Open". Robert Klarer has promised to provide wording. 20407</blockquote> 20408 20409 20410 20411<p><b>Proposed resolution:</b></p> 20412 20413 20414 20415 20416 20417<hr> 20418<h3><a name="1154"></a>1154. <tt>complex</tt> should accept integral types</h3> 20419<p><b>Section:</b> 26.4 [complex.numbers] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 20420 <b>Submitter:</b> LWG <b>Opened:</b> 2009-06-28 <b>Last modified:</b> 2009-10-26</p> 20421<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#complex.numbers">issues</a> in [complex.numbers].</p> 20422<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 20423<p><b>Discussion:</b></p> 20424 20425<p><b>Addresses FR 35</b></p> 20426 20427<p><b>Description</b></p> 20428 <p>Instantiations of the class 20429 template <tt>complex<></tt> have to be allowed for integral 20430 types, to reflect existing practice and ISO standards 20431 (LIA-III).</p> 20432 20433<p><b>Suggestion</b></p> 20434 20435<p><i>[ 204362009-10-26 Proposed wording in 20437<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n3002.pdf">N3002</a>. 20438]</i></p> 20439 20440 20441 20442 20443<p><b>Proposed resolution:</b></p> 20444Adopt 20445<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n3002.pdf">N3002</a>. 20446 20447 20448 20449 20450 20451<hr> 20452<h3><a name="1156"></a>1156. Constraints on bitmask and enumeration types to be tightened</h3> 20453<p><b>Section:</b> 17.5.2.1.2 [enumerated.types], 17.5.2.1.3 [bitmask.types] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 20454 <b>Submitter:</b> LWG <b>Opened:</b> 2009-06-28 <b>Last modified:</b> 2009-10-27</p> 20455<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 20456<p><b>Discussion:</b></p> 20457 20458<p><b>Addresses UK 165</b></p> 20459 20460<p><b>Description</b></p> 20461 <p>Constraints on 20462 bitmask and enumeration types were supposed to be tightened 20463 up as part of the motivation for the <tt>constexpr</tt> feature - 20464 see paper 20465 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2235.pdf">N2235</a> 20466 for details</p> 20467<p><b>Suggestion</b></p> 20468 <p>Adopt wording in line with the motivation 20469 described in 20470 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2235.pdf">N2235</a></p> 20471<p><b>Notes</b></p> 20472 <p>Robert Klarer to review</p> 20473 20474<p><i>[ 204752009 Santa Cruz: 20476]</i></p> 20477 20478 20479<blockquote> 20480Move to Open. Ping Robert Klarer to provide wording, using N2235 as 20481guidance. 20482</blockquote> 20483 20484 20485 20486<p><b>Proposed resolution:</b></p> 20487 20488 20489 20490 20491 20492<hr> 20493<h3><a name="1157"></a>1157. Local types can now instantiate templates</h3> 20494<p><b>Section:</b> 17.6.3.2.1 [namespace.std] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 20495 <b>Submitter:</b> LWG <b>Opened:</b> 2009-06-28 <b>Last modified:</b> 2009-10-21</p> 20496<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 20497<p><b>Discussion:</b></p> 20498 20499<p><b>Addresses UK 175</b></p> 20500 20501<p><b>Description</b></p> 20502 <p>Local types can 20503 now be used to instantiate templates, but don't have 20504 external linkage.</p> 20505<p><b>Suggestion</b></p> 20506 <p>Remove the reference to external linkage.</p> 20507 20508<p><b>Notes</b></p> 20509<p>We accept the proposed solution. Martin will draft an issue.</p> 20510 20511<p><i>[ 205122009-07-28 Alisdair provided wording. 20513]</i></p> 20514 20515 20516<p><i>[ 205172009-10 Santa Cruz: 20518]</i></p> 20519 20520 20521<blockquote> 20522Moved to Ready. 20523</blockquote> 20524 20525 20526 20527<p><b>Proposed resolution:</b></p> 20528<p> 2052917.6.3.2.1 [namespace.std] 20530</p> 20531<p> 20532Strike "of external linkage" in p1 and p2: 20533</p> 20534 20535<blockquote> 20536<p> 20537-1- The behavior of a C++ program is undefined if it adds declarations or 20538definitions to namespace <tt>std</tt> or to a namespace within namespace <tt>std</tt> 20539unless otherwise specified. A program may add a concept map for any 20540standard library concept or a template specialization for any standard 20541library template to namespace <tt>std</tt> only if the declaration depends on a 20542user-defined type <del>of external linkage</del> and the specialization meets the 20543standard library requirements for the original template and is not 20544explicitly prohibited.<sup>179</sup> 20545</p> 20546 20547<p> 20548-2- The behavior of a C++ program is undefined if it declares 20549</p> 20550<ul> 20551<li> 20552an explicit specialization of any member function of a standard library 20553class template, or 20554</li> 20555<li> 20556an explicit specialization of any member function template of a standard 20557library class or class template, or 20558</li> 20559<li> 20560an explicit or partial specialization of any member class template of a 20561standard library class or class template. 20562</li> 20563</ul> 20564<p> 20565A program may explicitly instantiate a template defined in the standard 20566library only if the declaration depends on the name of a user-defined 20567type <del>of external linkage</del> and the instantiation meets the standard 20568library requirements for the original template. 20569</p> 20570</blockquote> 20571 20572 20573 20574 20575 20576 20577<hr> 20578<h3><a name="1158"></a>1158. Encouragement to use monotonic clock</h3> 20579<p><b>Section:</b> 30.2.4 [thread.req.timing] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Tentatively Ready</a> 20580 <b>Submitter:</b> LWG <b>Opened:</b> 2009-06-28 <b>Last modified:</b> 2009-10-31</p> 20581<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20Ready">Tentatively Ready</a> status.</p> 20582<p><b>Discussion:</b></p> 20583 20584<p><b>Addresses UK 322, US 96</b></p> 20585 20586<p><b>Description</b></p> 20587 <p>Not all systems 20588 can provide a monotonic clock. How are they expected to 20589 treat a _for function?</p> 20590<p><b>Suggestion</b></p> 20591 <p>Add at least a note explaining the intent 20592 for systems that do not support a monotonic clock.</p> 20593 20594<p><b>Notes</b></p> 20595<p>Create an issue, together with UK 96. Note that the specification as is 20596 already allows a non-monotonic clock due to the word “should” rather than 20597 “shall”. If this wording is kept, a footnote should be added to make the 20598 meaning clear.</p> 20599 20600<p><i>[ 2009-06-29 Beman provided a proposed resolution. ] </i></p> 20601 20602<p><i>[ 206032009-10-31 Howard adds: 20604]</i></p> 20605 20606 20607<blockquote> 20608Set to Tentatively Ready after 5 positive votes on c++std-lib. 20609</blockquote> 20610 20611 20612 20613<p><b>Proposed resolution:</b></p> 20614 20615<p><i>Change Timing specifications 30.2.4 [thread.req.timing] as indicated:</i></p> 20616 20617<p>The member functions whose names end in <tt>_for</tt> take an argument that 20618specifies a relative time. Implementations 20619<del>should</del> <ins>are encouraged but not required to</ins> use a 20620monotonic clock to measure time for these functions.</p> 20621 20622 20623 20624 20625 20626 20627<hr> 20628<h3><a name="1159"></a>1159. Unclear spec for <tt>resource_deadlock_would_occur</tt></h3> 20629<p><b>Section:</b> 30.4.3.2.2 [thread.lock.unique.locking] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 20630 <b>Submitter:</b> LWG <b>Opened:</b> 2009-06-28 <b>Last modified:</b> 2009-07-04</p> 20631<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#thread.lock.unique.locking">active issues</a> in [thread.lock.unique.locking].</p> 20632<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#thread.lock.unique.locking">issues</a> in [thread.lock.unique.locking].</p> 20633<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 20634<p><b>Discussion:</b></p> 20635 20636<p><b>Addresses UK 327, UK 328</b></p> 20637 20638<p><b>UK 327 Description</b></p> 20639 <p>Not clear what 20640 the specification for error condition 20641 <tt>resource_deadlock_would_occur</tt> means. It is perfectly 20642 possible for this thread to own the mutex without setting 20643 owns to true on this specific lock object. It is also 20644 possible for lock operations to succeed even if the thread 20645 does own the mutex, if the mutex is recursive. Likewise, if 20646 the mutex is not recursive and the mutex has been locked 20647 externally, it is not always possible to know that this 20648 error condition should be raised, depending on the host 20649 operating system facilities. It is possible that 'i.e.' was 20650 supposed to be 'e.g.' and that suggests that recursive 20651 locks are not allowed. That makes sense, as the 20652 exposition-only member owns is boolean and not a integer to 20653 count recursive locks.</p> 20654 20655<p><b>UK 327 Suggestion</b></p> 20656 <p>Add a precondition <tt>!owns</tt>. Change the 'i.e.' 20657 in the error condition to be 'e.g.' to allow for this 20658 condition to propogate deadlock detection by the host OS.</p> 20659<p><b>UK 327 Notes</b></p> 20660<p>Create an issue. Assigned to Lawrence Crowl. Note: not sure what try_lock 20661 means for recursive locks when you are the owner. POSIX has language on 20662 this, which should ideally be followed. Proposed fix is not quite right, for 20663 example, try_lock should have different wording from lock.</p> 20664 20665<p><b>UK 328 Description</b></p> 20666 20667 <p>There is a missing precondition that <tt>owns</tt> 20668 is true, or an <tt>if(owns)</tt> test is missing from the effect 20669 clause</p> 20670<p><b>UK 328 Suggestion</b></p> 20671 <p>Add a 20672 precondition that <tt>owns == true</tt>. Add an error condition to 20673 detect a violation, rather than yield undefined behaviour.</p> 20674<p><b>UK 328 Notes</b></p> 20675<p>Handle in same issue as UK 327. Also uncertain that the proposed resolution 20676 is the correct one.</p> 20677 20678 20679 20680 20681<p><b>Proposed resolution:</b></p> 20682 20683 20684 20685 20686 20687<hr> 20688<h3><a name="1169"></a>1169. <tt>num_get</tt> not fully compatible with <tt>strto*</tt></h3> 20689<p><b>Section:</b> 22.4.2.1.2 [facet.num.get.virtuals] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 20690 <b>Submitter:</b> Cosmin Truta <b>Opened:</b> 2009-07-04 <b>Last modified:</b> 2009-07-07</p> 20691<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#facet.num.get.virtuals">active issues</a> in [facet.num.get.virtuals].</p> 20692<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#facet.num.get.virtuals">issues</a> in [facet.num.get.virtuals].</p> 20693<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 20694<p><b>Discussion:</b></p> 20695<p> 20696As specified in the latest draft, 20697<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2914.pdf">N2914</a>, 20698<code>num_get</code> is still not fully compatible with the following C 20699functions: <code>strtoul</code>, <code>strtoull</code>, 20700<code>strtof</code> and 20701<code>strtod</code>. 20702</p> 20703<p> 20704In C, when conversion of a string to an unsigned integer type falls 20705outside the 20706representable range, <code>strtoul</code> and <code>strtoull</code> return 20707<code>ULONG_MAX</code> and <code>ULLONG_MAX</code>, respectively, 20708regardless 20709whether the input field represents a positive or a negative value. 20710On the other hand, the result of <code>num_get</code> conversion of 20711negative 20712values to unsigned integer types is zero. This raises a compatibility 20713issue. 20714</p> 20715<p> 20716Moreover, in C, when conversion of a string to a floating-point type falls 20717outside the representable range, <code>strtof</code>, <code>strtod</code> 20718and 20719<code>strtold</code> return <code>�HUGE_VALF</code>, 20720<code>�HUGE_VAL</code> and <code>�HUGE_VALL</code>, respectively. 20721On the other hand, the result of <code>num_get</code> conversion of such 20722out-of-range floating-point values results in the most positive/negative 20723representable value. 20724Although many C library implementations do implement <code>HUGE_VAL</code> 20725(etc.) as the highest representable (which is, usually, the infinity), 20726this 20727isn't required by the C standard. The C library specification makes no 20728statement regarding the value of <code>HUGE_VAL</code> and friends, which 20729potentially raises the same compatibility issue as in the above case of 20730unsigned integers. 20731In addition, neither C nor C++ define symbolic constants for the maximum 20732representable floating-point values (they only do so only for the maximum 20733representable <i>finite</i> floating-point values), which raises a 20734usability 20735issue (it would be hard for the programmer to check the result of 20736<code>num_get</code> against overflow). 20737</p> 20738<p> 20739As such, we propose to adjust the specification of <code>num_get</code> to 20740closely follow the behavior of all of its underlying C functions. 20741</p> 20742 20743 20744<p><b>Proposed resolution:</b></p> 20745 20746<p> 20747Change 22.4.2.1.2 [facet.num.get.virtuals] as follows: 20748</p> 20749<blockquote> 20750<p> 20751<b>Stage 3:</b> 20752The sequence of <code>char</code>s accumulated in stage 2 (the field) is 20753converted to a numeric value by the rules of one of the functions declared in 20754the header <code><cstdlib></code>: 20755</p> 20756<ul> 20757<li>For a signed integer value, the function <code>strtoll</code>.</li> 20758<li>For an unsigned integer value, the function <code>strtoull</code>.</li> 20759<li><ins>For a <code>float</code> value, the function 20760 <code>strtof</code>.</ins></li> 20761<li><ins>For a <code>double</code> value, the function 20762 <code>strtod</code>.</ins></li> 20763<li>For a <del>floating-point</del> <ins><code>long double</code></ins> 20764 value, the function <code>strtold</code>.</li> 20765</ul> 20766<p> 20767The numeric value to be stored can be one of: 20768</p> 20769<ul> 20770<li>zero, if the conversion function fails to convert the entire field. 20771 <del><code>ios_base::failbit</code> is assigned to <code>err</code>.</del></li> 20772<li>the most positive <ins>(or negative)</ins> representable value, if 20773 the field <ins>to be converted to a signed integer type</ins> represents a 20774 value too large positive <ins>(or negative)</ins> to be represented in 20775 <code>val</code>. 20776 <del><code>ios_base::failbit</code> is assigned to <code>err</code>.</del></li> 20777<li><del>the most negative representable value or zero for an unsigned integer 20778 type, if the field represents a value too large negative to be represented 20779 in <code>val</code>. 20780 <code>ios_base::failbit</code> is assigned to <code>err</code>.</del></li> 20781<li><ins>the most positive representable value, if the field to be converted to 20782 an unsigned integer type represents a value that cannot be represented in 20783 <code>val</code>.</ins></li> 20784<li>the converted value, otherwise.</li> 20785</ul> 20786<p> 20787The resultant numeric value is stored in <code>val</code>. 20788<ins>If the conversion function fails to convert the entire field, or if the 20789field represents a value outside the range of representable values, 20790<code>ios_base::failbit</code> is assigned to <code>err</code>.</ins> 20791</p> 20792</blockquote> 20793 20794 20795 20796 20797 20798 20799<hr> 20800<h3><a name="1170"></a>1170. String <i>char-like types</i> no longer PODs</h3> 20801<p><b>Section:</b> 21.1 [strings.general] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 20802 <b>Submitter:</b> Beman Dawes <b>Opened:</b> 2009-06-22 <b>Last modified:</b> 2009-11-04</p> 20803<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 20804<p><b>Discussion:</b></p> 20805 20806<p><b>Addresses UK 218</b></p> 20807 20808<p>Prior to the introduction of constant expressions into the library, 20809<tt>basic_string</tt> elements had to be POD types, and thus had to be both trivially 20810copyable and standard-layout. This ensured that they could be memcpy'ed and 20811would be compatible with other libraries and languages, particularly the C 20812language and its library.</p> 20813<p> 20814<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2349.pdf">N2349</a>, 20815Constant Expressions in the Standard Library Revision 2, changed the 20816requirement in 21/1 from "POD type" to "literal type". That change had the 20817effect of removing the trivially copyable and standard-layout requirements from 20818<tt>basic_string</tt> elements.</p> 20819<p>This means that <tt>basic_string</tt> elements no longer are guaranteed to be 20820memcpy'able, and are no longer guaranteed to be standard-layout types:</p> 20821<blockquote> 20822 <p>3.9/p2 and 3.9/p3 both make it clear that a "trivially copyable type" is 20823 required for memcpy to be guaranteed to work.</p> 20824 <p>Literal types (3.9p12) may have a non-trivial copy assignment operator, and 20825 that violates the trivially copyable requirements given in 9/p 6, bullet item 20826 2. </p> 20827 <p>Literal types (3.9p12) have no standard-layout requirement, either.</p> 20828</blockquote> 20829<p>This situation probably arose because the wording for "Constant Expressions 20830in the Standard Library" was in process at the same time the C++ POD 20831deconstruction wording was in process. </p> 20832<p>Since trivially copyable types meet the C++0x requirements for literal types, 20833and thus work with constant expressions, it seems an easy fix to revert the 20834<tt>basic_string</tt> element wording to its original state.</p> 20835 20836 <p><i>[ 20837 2009-07-28 Alisdair adds: 20838 ]</i></p> 20839 20840 20841<blockquote> 20842When looking for any resolution for this issue, consider the definition of 20843"character container type" in 17.3.4 [defns.character.container]. This 20844does require the character type to be a POD, and this term is used in a 20845number of places through clause 21 and 28. This suggests the PODness 20846constraint remains, but is much more subtle than before. Meanwhile, I 20847suspect the change from POD type to literal type was intentional with 20848the assumption that trivially copyable types with 20849non-trivial-but-constexpr constructors should serve as well. I don't 20850believe the current wording offers the right guarantees for either of 20851the above designs. 20852</blockquote> 20853 20854<p><i>[ 208552009-11-04 Howard modifies proposed wording to disallow array types as 20856char-like types. 20857]</i></p> 20858 20859 20860 20861 20862<p><b>Proposed resolution:</b></p> 20863 20864<p><i>Change General 21.1 [strings.general] as indicated:</i></p> 20865<blockquote> 20866<p>This Clause describes components for manipulating sequences of any 20867<del>literal</del> <ins>non-array POD</ins> (3.9) type. In this Clause 20868such types are called <i>char-like types</i>, and objects of char-like 20869types are called <i>char-like objects</i> or simply 20870<i>characters</i>.</p> 20871</blockquote> 20872 20873 20874 20875 20876 20877 20878<hr> 20879<h3><a name="1171"></a>1171. duration types should be literal</h3> 20880<p><b>Section:</b> 20.9.3 [time.duration] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 20881 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-07-06 <b>Last modified:</b> 2009-10-31</p> 20882<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#time.duration">active issues</a> in [time.duration].</p> 20883<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#time.duration">issues</a> in [time.duration].</p> 20884<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 20885<p><b>Discussion:</b></p> 20886<p> 20887The <tt>duration</tt> types in 20.9.3 [time.duration] are exactly the sort of type 20888that should be "literal types" in the new standard. Likewise, 20889arithmetic operations on <tt>duration</tt>s should be declared <tt>constexpr</tt>. 20890</p> 20891 20892<p><i>[ 208932009-09-21 Daniel adds: 20894]</i></p> 20895 20896 20897<blockquote> 20898An alternative (and possibly preferable solution for potentially 20899heap-allocating big_int representation types) would be to ask the core 20900language to allow references to <tt>const</tt> literal types as feasible 20901arguments for <tt>constexpr</tt> functions. 20902</blockquote> 20903 20904<p><i>[ 209052009-10-30 Alisdair adds: 20906]</i></p> 20907 20908 20909<blockquote> 20910<p> 20911I suggest this issue moves from New to Open. 20912</p> 20913 20914<p> 20915Half of this issue was dealt with in paper 20916<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2994.html">n2994</a> 20917on constexpr constructors. 20918</p> 20919 20920<p> 20921The other half (duration arithmetic) is on hold pending Core support for 20922<tt>const &</tt> in <tt>constexpr</tt> functions. 20923</p> 20924 20925</blockquote> 20926 20927 20928 20929<p><b>Proposed resolution:</b></p> 20930<p> 20931Add <tt>constexpr</tt> to declaration of following functions and constructors: 20932</p> 20933<p> 20934p1 20.9 [time] 20935</p> 20936 20937<blockquote> 20938<p> 20939<b>Header <tt><chrono></tt> synopsis</b> 20940</p> 20941 20942<p><i>[Draughting note - observe switch to pass-by-value to support constexpr]</i></p> 20943 20944 20945<pre><i>// duration arithmetic</i> 20946template <class Rep1, class Period1, class Rep2, class Period2> 20947 typename common_type<duration<Rep1, Period1>, duration<Rep2, Period2>>::type 20948 <ins>constexpr</ins> operator+(<del>const</del> duration<Rep1, Period1><del>&</del> lhs, <del>const</del> duration<Rep2, Period2><del>&</del> rhs); 20949template <class Rep1, class Period1, class Rep2, class Period2> 20950 typename common_type<duration<Rep1, Period1>, duration<Rep2, Period2>>::type 20951 <ins>constexpr</ins> operator-(<del>const</del> duration<Rep1, Period1><del>&</del> lhs, <del>const</del> duration<Rep2, Period2><del>&</del> rhs); 20952template <class Rep1, class Period, class Rep2> 20953 duration<typename common_type<Rep1, Rep2>::type, Period> 20954 <ins>constexpr</ins> operator*(<del>const</del> duration<Rep1, Period><del>&</del> d, <del>const</del> Rep2<del>&</del> s); 20955template <class Rep1, class Period, class Rep2> 20956 duration<typename common_type<Rep1, Rep2>::type, Period> 20957 <ins>constexpr</ins> operator*(<del>const</del> Rep1<del>&</del> s, <del>const</del> duration<Rep2, Period><del>&</del> d); 20958template <class Rep1, class Period, class Rep2> 20959 duration<typename common_type<Rep1, Rep2>::type, Period> 20960 <ins>constexpr</ins> operator/(<del>const</del> duration<Rep1, Period><del>&</del> d, <del>const</del> Rep2<del>&</del> s); 20961template <class Rep1, class Period1, class Rep2, class Period2> 20962 typename common_type<Rep1, Rep2>::type 20963 <ins>constexpr</ins> operator/(<del>const</del> duration<Rep1, Period1><del>&</del> lhs, <del>const</del> duration<Rep2, Period2><del>&</del> rhs); 20964 20965<i>// duration comparisons</i> 20966template <class Rep1, class Period1, class Rep2, class Period2> 20967 <ins>constexpr</ins> bool operator==(<del>const</del> duration<Rep1, Period1><del>&</del> lhs, <del>const</del> duration<Rep2, Period2><del>&</del> rhs); 20968template <class Rep1, class Period1, class Rep2, class Period2> 20969 <ins>constexpr</ins> bool operator!=(<del>const</del> duration<Rep1, Period1><del>&</del> lhs, <del>const</del> duration<Rep2, Period2><del>&</del> rhs); 20970template <class Rep1, class Period1, class Rep2, class Period2> 20971 <ins>constexpr</ins> bool operator< (<del>const</del> duration<Rep1, Period1><del>&</del> lhs, <del>const</del> duration<Rep2, Period2><del>&</del> rhs); 20972template <class Rep1, class Period1, class Rep2, class Period2> 20973 <ins>constexpr</ins> bool operator<=(<del>const</del> duration<Rep1, Period1><del>&</del> lhs, <del>const</del> duration<Rep2, Period2><del>&</del> rhs); 20974template <class Rep1, class Period1, class Rep2, class Period2> 20975 <ins>constexpr</ins> bool operator> (<del>const</del> duration<Rep1, Period1><del>&</del> lhs, <del>const</del> duration<Rep2, Period2><del>&</del> rhs); 20976template <class Rep1, class Period1, class Rep2, class Period2> 20977 <ins>constexpr</ins> bool operator>=(<del>const</del> duration<Rep1, Period1><del>&</del> lhs, <del>const</del> duration<Rep2, Period2><del>&</del> rhs); 20978 20979<i>// duration_cast</i> 20980template <class ToDuration, class Rep, class Period> 20981 <ins>constexpr</ins> ToDuration duration_cast(<del>const</del> duration<Rep, Period><del>&</del> d); 20982</pre> 20983 20984<p> 20985<b>20.9.3 [time.duration]</b> 20986</p> 20987 20988<pre>template <class Rep, class Period = ratio<1>> 20989class duration { 20990 .... 20991public: 20992 <i>// 20.9.3.1, construct/copy/destroy:</i> 20993 <ins>constexpr</ins> duration() = default; 20994 20995 template <class Rep2> 20996 <ins>constexpr</ins> explicit duration(const Rep2& r); 20997 template <class Rep2, class Period2> 20998 <ins>constexpr</ins> duration(const duration<Rep2, Period2>& d); 20999 21000 <ins>constexpr</ins> duration(const duration&) = default; 21001 21002 <i>// 20.9.3.2, observer:</i> 21003 <ins>constexpr</ins> rep count() const; 21004 21005 <i>// 20.9.3.3, arithmetic:</i> 21006 <ins>constexpr</ins> duration operator+() const; 21007 <ins>constexpr</ins> duration operator-() const; 21008 ... 21009 21010}; 21011</pre> 21012</blockquote> 21013<p><i>[ 21014Note - this edit already seems assumed by definition of the duration static members <tt>zero/min/max</tt>. 21015They cannot meaningfully be <tt>constexpr</tt> without this change. 21016]</i></p> 21017 21018 21019 21020 21021 21022 21023<hr> 21024<h3><a name="1173"></a>1173. "Equivalence" wishy-washiness</h3> 21025<p><b>Section:</b> 17 [library] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 21026 <b>Submitter:</b> David Abrahams <b>Opened:</b> 2009-07-14 <b>Last modified:</b> 2009-10-20</p> 21027<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#library">active issues</a> in [library].</p> 21028<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#library">issues</a> in [library].</p> 21029<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 21030<p><b>Discussion:</b></p> 21031<p> 21032Issue: The <tt>CopyConstructible</tt> requirements are wishy-washy. It requires 21033that the copy is "equivalent" to the original, but "equivalent" is never 21034defined. 21035</p> 21036<p> 21037I believe this to be an example of a more general lack of rigor around 21038copy and assignment, although I haven't done the research to dig up all 21039the instances. 21040</p> 21041<p> 21042It's a problem because if you don't know what <tt>CopyConstructible</tt> means, 21043you also don't know what it means to copy a pair of <tt>CopyConstructible</tt> 21044types. It doesn't prevent us from writing code, but it is a hole in our 21045ability to understand the meaning of copy. 21046</p> 21047<p> 21048Furthermore, I'm pretty sure that vector's copy constructor doesn't 21049require the elements to be <tt>EqualityComparable</tt>, so that table is actually 21050referring to some ill-defined notion of equivalence when it uses ==. 21051</p> 21052 21053<p><i>[ 210542009 Santa Cruz: 21055]</i></p> 21056 21057 21058<blockquote> 21059Move to "Open". Dave is right that this is a big issue. Paper D2987 21060("Defining Move Special Member Functions", Bjarne Stroustrup and 21061Lawrence Crowl) touches on this but does not solve it. This issue is 21062discussed in Elements of Programming. 21063</blockquote> 21064 21065 21066 21067<p><b>Proposed resolution:</b></p> 21068 21069 21070 21071 21072 21073<hr> 21074<h3><a name="1175"></a>1175. <tt>unordered</tt> complexity</h3> 21075<p><b>Section:</b> 23.2.5 [unord.req] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 21076 <b>Submitter:</b> Pablo Halpern <b>Opened:</b> 2009-07-17 <b>Last modified:</b> 2009-07-19</p> 21077<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#unord.req">active issues</a> in [unord.req].</p> 21078<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#unord.req">issues</a> in [unord.req].</p> 21079<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 21080<p><b>Discussion:</b></p> 21081<p> 21082When I look at the <tt>unordered_*</tt> constructors, I think the complexity is poorly 21083described and does not follow the style of the rest of the standard. 21084</p> 21085 21086<p> 21087The complexity for the default constructor is specified as constant. 21088 Actually, it is proportional to <tt>n</tt>, but there are no invocations of 21089<tt>value_type</tt> constructors or other <tt>value_type</tt> operations. 21090</p> 21091 21092<p> 21093For the iterator-based constructor the complexity should be: 21094</p> 21095 21096<blockquote> 21097<i>Complexity:</i> exactly <tt>n</tt> calls to construct <tt>value_type</tt> 21098from <tt>InputIterator::value_type</tt> (where <tt>n = distance(f,l)</tt>). 21099The number of calls to <tt>key_equal::operator()</tt> is proportional to 21100<tt>n</tt> in the average case and <tt>n*n</tt> in the worst case. 21101</blockquote> 21102 21103 21104 21105<p><b>Proposed resolution:</b></p> 21106<p> 21107</p> 21108 21109 21110 21111 21112 21113<hr> 21114<h3><a name="1176"></a>1176. Make <tt>thread</tt> constructor non-variadic</h3> 21115<p><b>Section:</b> 30.3.1.2 [thread.thread.constr] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 21116 <b>Submitter:</b> Howard Hinnant <b>Opened:</b> 2009-07-18 <b>Last modified:</b> 2009-07-18</p> 21117<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#thread.thread.constr">active issues</a> in [thread.thread.constr].</p> 21118<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#thread.thread.constr">issues</a> in [thread.thread.constr].</p> 21119<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 21120<p><b>Discussion:</b></p> 21121<p> 21122The variadic <tt>thread</tt> constructor is causing controversy, e.g. 21123<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2901.pdf">N2901</a>. 21124This issue has been created as a placeholder for this course of action. 21125</p> 21126 21127<blockquote><pre>template <class F<del>, class ...Args</del>> thread(F&& f<del>, Args&&... args</del>); 21128</pre></blockquote> 21129 21130<p> 21131See <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#929">929</a> for wording which specifies an rvalue-ref signature but 21132with "decay behavior", but using variadics. 21133</p> 21134 21135 21136<p><b>Proposed resolution:</b></p> 21137<p> 21138</p> 21139 21140 21141 21142 21143 21144<hr> 21145<h3><a name="1177"></a>1177. Improve "diagnostic required" wording</h3> 21146<p><b>Section:</b> 20.9.3 [time.duration] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 21147 <b>Submitter:</b> Howard Hinnant <b>Opened:</b> 2009-07-18 <b>Last modified:</b> 2009-10-26</p> 21148<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#time.duration">active issues</a> in [time.duration].</p> 21149<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#time.duration">issues</a> in [time.duration].</p> 21150<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 21151<p><b>Discussion:</b></p> 21152<p> 21153"diagnostic required" has been used (by me) for code words meaning "use 21154<tt>enable_if</tt> to constrain templated functions. This needs to be 21155improved by referring to the function signature as not participating in 21156the overload set, and moving this wording to a <i>Remarks</i> paragraph. 21157</p> 21158 21159<p><i>[ 211602009-10 Santa Cruz: 21161]</i></p> 21162 21163 21164<blockquote> 21165Moved to Ready. 21166</blockquote> 21167 21168 21169 21170<p><b>Proposed resolution:</b></p> 21171<p><i>[ 21172This proposed resolution addresses <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#947">947</a> and <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#974">974</a>. 21173]</i></p> 21174 21175 21176<ol> 21177<li> 21178<p> 21179Change 20.9.3.1 [time.duration.cons]: 21180</p> 21181 21182<blockquote> 21183<pre>template <class Rep2> 21184 explicit duration(const Rep2& r); 21185</pre> 21186<blockquote> 21187<p> 21188<i><del>Requires:</del> <ins>Remarks:</ins></i> 21189<tt>Rep2</tt> shall be implicitly convertible to <tt>rep</tt> and 21190</p> 21191<ul> 21192<li> 21193<tt>treat_as_floating_point<rep>::value</tt> shall be <tt>true</tt> or 21194</li> 21195<li> 21196<tt>treat_as_floating_point<Rep2>::value</tt> shall be <tt>false</tt>. 21197</li> 21198</ul> 21199<p> 21200<del>Diagnostic required</del> <ins>If these constraints are not met, this 21201constructor shall not participate in overload resolution</ins>. [<i>Example:</i> 21202</p> 21203<blockquote><pre>duration<int, milli> d(3); // OK 21204duration<int, milli> d(3.5); // error 21205</pre></blockquote> 21206 21207<p> 21208— <i>end example</i>] 21209</p> 21210 21211<p> 21212<i>Effects:</i> Constructs an object of type <tt>duration</tt>. 21213</p> 21214 21215<p> 21216<i>Postcondition:</i> <tt>count() == static_cast<rep>(r)</tt>. 21217</p> 21218 21219</blockquote> 21220 21221<pre>template <class Rep2, class Period2> 21222 duration(const duration<Rep2, Period2>& d); 21223</pre> 21224<blockquote> 21225<p> 21226<i><del>Requires:</del> <ins>Remarks:</ins></i> <tt>treat_as_floating_point<rep>::value</tt> shall be <tt>true</tt> or 21227<tt>ratio_divide<Period2, period>::type::den</tt> shall be 1<del>. Diagnostic 21228required</del><ins>, else this constructor shall not participate in overload 21229resolution</ins>. [<i>Note:</i> This requirement prevents implicit truncation error 21230when converting between integral-based duration types. Such a 21231construction could easily lead to confusion about the value of the 21232duration. — <i>end note</i>] [<i>Example:</i> 21233</p> 21234 21235<blockquote><pre>duration<int, milli> ms(3); 21236duration<int, micro> us = ms; // OK 21237duration<int, milli> ms2 = us; // error 21238</pre></blockquote> 21239 21240<p> 21241— <i>end example</i>] 21242</p> 21243 21244<p> 21245<i>Effects:</i> Constructs an object of type <tt>duration</tt>, constructing 21246<tt>rep_</tt> from 21247<tt>duration_cast<duration>(d).count()</tt>. 21248</p> 21249 21250</blockquote> 21251 21252 21253</blockquote> 21254</li> 21255 21256<li> 21257<p> 21258Change the following paragraphs in 20.9.3.5 [time.duration.nonmember]: 21259</p> 21260 21261<blockquote> 21262<pre>template <class Rep1, class Period, class Rep2> 21263 duration<typename common_type<Rep1, Rep2>::type, Period> 21264 operator*(const duration<Rep1, Period>& d, const Rep2& s); 21265</pre> 21266<blockquote> 21267<i><del>Requires</del> <ins>Remarks</ins>:</i> <tt>Rep2</tt> shall be implicitly convertible to 21268<tt>CR(Rep1, Rep2)</tt><ins>, else this signature shall not participate in 21269overload resolution</ins>. <del>Diagnostic required.</del> 21270</blockquote> 21271 21272<pre>template <class Rep1, class Period, class Rep2> 21273 duration<typename common_type<Rep1, Rep2>::type, Period> 21274 operator*(const Rep1& s, const duration<Rep2, Period>& d); 21275</pre> 21276<blockquote> 21277<i><del>Requires</del> <ins>Remarks</ins>:</i> <tt>Rep1</tt> shall be implicitly convertible to 21278<tt>CR(Rep1, Rep2)</tt><ins>, else this signature shall not participate in 21279overload resolution</ins>. <del>Diagnostic required.</del> 21280</blockquote> 21281 21282<pre>template <class Rep1, class Period, class Rep2> 21283 duration<typename common_type<Rep1, Rep2>::type, Period> 21284 operator/(const duration<Rep1, Period>& d, const Rep2& s); 21285</pre> 21286<blockquote> 21287<i><del>Requires</del> <ins>Remarks</ins>:</i> <tt>Rep2</tt> shall be implicitly convertible to 21288<tt>CR(Rep1, Rep2)</tt> and <tt>Rep2</tt> shall not be an instantiation of 21289<tt>duration</tt><ins>, else this signature shall not participate in 21290overload resolution</ins>. <del>Diagnostic required.</del> 21291</blockquote> 21292 21293<pre>template <class Rep1, class Period, class Rep2> 21294 duration<typename common_type<Rep1, Rep2>::type, Period> 21295 operator%(const duration<Rep1, Period>& d, const Rep2& s); 21296</pre> 21297<blockquote> 21298<i><del>Requires</del> <ins>Remarks</ins>:</i> <tt>Rep2</tt> shall be implicitly convertible to 21299<tt>CR(Rep1, Rep2)</tt> and <tt>Rep2</tt> shall not be an instantiation of 21300<tt>duration</tt><ins>, else this signature shall not participate in 21301overload resolution</ins>. <del>Diagnostic required.</del> 21302</blockquote> 21303 21304</blockquote> 21305</li> 21306 21307<li> 21308<p> 21309Change the following paragraphs in 20.9.3.7 [time.duration.cast]: 21310</p> 21311 21312<blockquote><pre>template <class ToDuration, class Rep, class Period> 21313 ToDuration duration_cast(const duration<Rep, Period>& d); 21314</pre> 21315 21316<blockquote> 21317<i><del>Requires</del> <ins>Remarks</ins>:</i> <tt>ToDuration</tt> shall be an instantiation of 21318<tt>duration</tt><ins>, else this signature shall not participate in 21319overload resolution</ins>. <del>Diagnostic required.</del> 21320</blockquote> 21321</blockquote> 21322</li> 21323 21324<li> 21325<p> 21326Change the following paragraphs in 20.9.4.7 [time.point.cast]: 21327</p> 21328 21329<blockquote><pre>template <class ToDuration, class Clock, class Duration> 21330 time_point<Clock, ToDuration> time_point_cast(const time_point<Clock, Duration>& t); 21331</pre> 21332 21333<blockquote> 21334<i><del>Requires</del> <ins>Remarks</ins>:</i> <tt>ToDuration</tt> shall be an instantiation of 21335<tt>duration</tt><ins>, else this signature shall not participate in 21336overload resolution</ins>. <del>Diagnostic required.</del> 21337</blockquote> 21338</blockquote> 21339</li> 21340</ol> 21341 21342 21343 21344 21345 21346 21347<hr> 21348<h3><a name="1180"></a>1180. Missing string_type member typedef in class <tt>sub_match</tt></h3> 21349<p><b>Section:</b> 28.9.1 [re.submatch.members] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 21350 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2009-07-25 <b>Last modified:</b> 2009-07-26</p> 21351<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 21352<p><b>Discussion:</b></p> 21353<p> 21354The definition of class template <tt>sub_match</tt> is strongly dependent 21355on the type <tt>basic_string<value_type></tt>, both in interface and effects, 21356but does not provide a corresponding typedef <tt>string_type</tt>, as e.g. 21357class <tt>match_results</tt> does, which looks like an oversight to me that 21358should be fixed. 21359</p> 21360 21361 21362<p><b>Proposed resolution:</b></p> 21363 21364<ol> 21365<li> 21366<p> 21367In the class template <tt>sub_match</tt> synopsis 28.9 [re.submatch]/1 21368change as indicated: 21369</p> 21370 21371<blockquote><pre>template <class BidirectionalIterator> 21372class sub_match : public std::pair<BidirectionalIterator, BidirectionalIterator> { 21373public: 21374 typedef typename iterator_traits<BidirectionalIterator>::value_type value_type; 21375 typedef typename iterator_traits<BidirectionalIterator>::difference_type difference_type; 21376 typedef BidirectionalIterator iterator; 21377 <ins>typedef basic_string<value_type> string_type;</ins> 21378 21379 bool matched; 21380 21381 difference_type length() const; 21382 operator <del>basic_string<value_type></del><ins>string_type</ins>() const; 21383 <del>basic_string<value_type></del><ins>string_type</ins> str() const; 21384 int compare(const sub_match& s) const; 21385 int compare(const <del>basic_string<value_type></del><ins>string_type</ins>& s) const; 21386 int compare(const value_type* s) const; 21387}; 21388</pre></blockquote> 21389</li> 21390 21391<li> 21392<p> 21393In 28.9.1 [re.submatch.members]/2 change as indicated: 21394</p> 21395 21396<blockquote><pre>operator <del>basic_string<value_type></del><ins>string_type</ins>() const; 21397</pre> 21398 21399<blockquote> 21400<i>Returns:</i> <tt>matched ? <del>basic_string<value_type></del> 21401<ins>string_type</ins>(first, second) : <del>basic_string<value_type></del> 21402<ins>string_type</ins>()</tt>. 21403</blockquote> 21404</blockquote> 21405</li> 21406 21407<li> 21408<p> 21409In 28.9.1 [re.submatch.members]/3 change as indicated: 21410</p> 21411 21412<blockquote><pre><del>basic_string<value_type></del><ins>string_type</ins> str() const; 21413</pre> 21414 21415<blockquote> 21416<i>Returns:</i> <tt>matched ? <del>basic_string<value_type></del> 21417<ins>string_type</ins>(first, second) : <del>basic_string<value_type></del> 21418<ins>string_type</ins>()</tt>. 21419</blockquote> 21420</blockquote> 21421</li> 21422</ol> 21423 21424 21425 21426 21427 21428 21429<hr> 21430<h3><a name="1181"></a>1181. Invalid <tt>sub_match</tt> comparison operators</h3> 21431<p><b>Section:</b> 28.9.2 [re.submatch.op] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 21432 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2009-07-25 <b>Last modified:</b> 2009-07-28</p> 21433<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#re.submatch.op">issues</a> in [re.submatch.op].</p> 21434<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 21435<p><b>Discussion:</b></p> 21436<p> 21437Several heterogeneous comparison operators of class template 21438<tt>sub_match</tt> are specified by return clauses that are not valid 21439in general. E.g. 28.9.2 [re.submatch.op]/7: 21440</p> 21441 21442<blockquote><pre>template <class BiIter, class ST, class SA> 21443bool operator==( 21444 const basic_string< 21445 typename iterator_traits<BiIter>::value_type, ST, SA>& lhs, 21446 const sub_match<BiIter>& rhs); 21447</pre> 21448<blockquote> 21449<i>Returns:</i> <tt>lhs == rhs.str()</tt>. 21450</blockquote> 21451</blockquote> 21452 21453<p> 21454The returns clause would be ill-formed for all cases where 21455<tt>ST != std::char_traits<iterator_traits<BiIter>::value_type></tt> 21456or <tt>SA != std::allocator<iterator_traits<BiIter>::value_type></tt>. 21457</p> 21458<p> 21459The generic character of the comparison was intended, so 21460there are basically two approaches to fix the problem: The 21461first one would define the semantics of the comparison 21462using the traits class <tt>ST</tt> (The semantic of <tt>basic_string::compare</tt> 21463is defined in terms of the compare function of the corresponding 21464traits class), the second one would define the semantics of the 21465comparison using the traits class 21466</p> 21467 21468<blockquote><pre>std::char_traits<iterator_traits<BiIter>::value_type> 21469</pre></blockquote> 21470 21471<p> 21472which is essentially identical to 21473</p> 21474 21475<blockquote><pre>std::char_traits<sub_match<BiIter>::value_type> 21476</pre></blockquote> 21477 21478<p> 21479I suggest to follow the second approach, because 21480this emphasizes the central role of the <tt>sub_match</tt> 21481object as part of the comparison and would also 21482make sure that a <tt>sub_match</tt> comparison using some 21483<tt>basic_string<char_t, ..></tt> always is equivalent to 21484a corresponding comparison with a string literal 21485because of the existence of further overloads (beginning 21486from 28.9.2 [re.submatch.op]/19). If users really want to 21487take advantage of their own <tt>traits::compare</tt>, they can 21488simply write a corresponding compare function that 21489does so. 21490</p> 21491 21492 21493<p><b>Proposed resolution:</b></p> 21494<ol> 21495<li> 21496<p> 21497In 28.9.2 [re.submatch.op] change as indicated: 21498</p> 21499 21500<ol type="a"> 21501<li> 21502 21503<p> 21504If <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1180">1180</a> is accepted: 21505</p> 21506 21507<blockquote> 21508<pre>template <class BiIter, class ST, class SA> 21509 bool operator==( 21510 const basic_string< 21511 typename iterator_traits<BiIter>::value_type, ST, SA>& lhs, 21512 const sub_match<BiIter>& rhs); 21513</pre> 21514<blockquote> 215157 <i>Returns:</i> <tt><del>lhs</del><ins>typename 21516sub_match<BiIter>::string_type(lhs.begin(), lhs.end())</ins> == 21517rhs.str()</tt>. 21518</blockquote> 21519 21520<pre>template <class BiIter, class ST, class SA> 21521 bool operator!=( 21522 const basic_string< 21523 typename iterator_traits<BiIter>::value_type, ST, SA>& lhs, 21524 const sub_match<BiIter>& rhs); 21525</pre> 21526 21527<blockquote> 215288 <i>Returns:</i> <tt><del>lhs</del><ins>typename 21529sub_match<BiIter>::string_type(lhs.begin(), lhs.end())</ins> != 21530rhs.str()</tt>. 21531</blockquote> 21532 21533<pre>template <class BiIter, class ST, class SA> 21534 bool operator<( 21535 const basic_string< 21536 typename iterator_traits<BiIter>::value_type, ST, SA>& lhs, 21537 const sub_match<BiIter>& rhs); 21538</pre> 21539 21540<blockquote> 215419 <i>Returns:</i> <tt><del>lhs</del><ins>typename 21542sub_match<BiIter>::string_type(lhs.begin(), lhs.end())</ins> < 21543rhs.str()</tt>. 21544</blockquote> 21545 21546<pre>template <class BiIter, class ST, class SA> 21547 bool operator>( 21548 const basic_string< 21549 typename iterator_traits<BiIter>::value_type, ST, SA>& lhs, 21550 const sub_match<BiIter>& rhs); 21551</pre> 21552 21553<blockquote> 2155410 <i>Returns:</i> <tt><del>lhs</del><ins>typename 21555sub_match<BiIter>::string_type(lhs.begin(), lhs.end())</ins> > 21556rhs.str()</tt>. 21557</blockquote> 21558 21559<pre>template <class BiIter, class ST, class SA> 21560 bool operator>=( 21561 const basic_string< 21562 typename iterator_traits<BiIter>::value_type, ST, SA>& lhs, 21563 const sub_match<BiIter>& rhs); 21564</pre> 21565 21566<blockquote> 2156711 <i>Returns:</i> <tt><del>lhs</del><ins>typename 21568sub_match<BiIter>::string_type(lhs.begin(), lhs.end())</ins> >= 21569rhs.str()</tt>. 21570</blockquote> 21571 21572<pre>template <class BiIter, class ST, class SA> 21573 bool operator<=( 21574 const basic_string< 21575 typename iterator_traits<BiIter>::value_type, ST, SA>& lhs, 21576 const sub_match<BiIter>& rhs); 21577</pre> 21578 21579<blockquote> 2158012 <i>Returns:</i> <tt><del>lhs</del><ins>typename 21581sub_match<BiIter>::string_type(lhs.begin(), lhs.end())</ins> <= 21582rhs.str()</tt>. 21583</blockquote> 21584 21585<pre>template <class BiIter, class ST, class SA> 21586 bool operator==(const sub_match<BiIter>& lhs, 21587 const basic_string< 21588 typename iterator_traits<BiIter>::value_type, ST, SA>& rhs); 21589</pre> 21590 21591<blockquote> 2159213 <i>Returns:</i> <tt>lhs.str() == <del>rhs</del><ins>typename 21593sub_match<BiIter>::string_type(rhs.begin(), rhs.end())</ins></tt>. 21594</blockquote> 21595 21596<pre>template <class BiIter, class ST, class SA> 21597 bool operator!=(const sub_match<BiIter>& lhs, 21598 const basic_string< 21599 typename iterator_traits<BiIter>::value_type, ST, SA>& rhs); 21600</pre> 21601 21602<blockquote> 2160314 <i>Returns:</i> <tt>lhs.str() != <del>rhs</del><ins>typename 21604sub_match<BiIter>::string_type(rhs.begin(), rhs.end())</ins></tt>. 21605</blockquote> 21606 21607<pre>template <class BiIter, class ST, class SA> 21608 bool operator<(const sub_match<BiIter>& lhs, 21609 const basic_string< 21610 typename iterator_traits<BiIter>::value_type, ST, SA>& rhs); 21611</pre> 21612 21613<blockquote> 2161415 <i>Returns:</i> <tt>lhs.str() < <del>rhs</del><ins>typename 21615sub_match<BiIter>::string_type(rhs.begin(), rhs.end())</ins></tt>. 21616</blockquote> 21617 21618<pre>template <class BiIter, class ST, class SA> 21619 bool operator>(const sub_match<BiIter>& lhs, 21620 const basic_string< 21621 typename iterator_traits<BiIter>::value_type, ST, SA>& rhs); 21622</pre> 21623 21624<blockquote> 2162516 <i>Returns:</i> <tt>lhs.str() > <del>rhs</del><ins>typename 21626sub_match<BiIter>::string_type(rhs.begin(), rhs.end())</ins></tt>. 21627</blockquote> 21628 21629<pre>template <class BiIter, class ST, class SA> 21630 bool operator>=(const sub_match<BiIter>& lhs, 21631 const basic_string< 21632 typename iterator_traits<BiIter>::value_type, ST, SA>& rhs); 21633</pre> 21634 21635<blockquote> 2163617 <i>Returns:</i> <tt>lhs.str() >= <del>rhs</del><ins>typename 21637sub_match<BiIter>::string_type(rhs.begin(), rhs.end())</ins></tt>. 21638</blockquote> 21639 21640<pre>template <class BiIter, class ST, class SA> 21641 bool operator<=(const sub_match<BiIter>& lhs, 21642 const basic_string< 21643 typename iterator_traits<BiIter>::value_type, ST, SA>& rhs); 21644</pre> 21645 21646<blockquote> 2164718 <i>Returns:</i> <tt>lhs.str() <= <del>rhs</del><ins>typename 21648sub_match<BiIter>::string_type(rhs.begin(), rhs.end())</ins></tt>. 21649</blockquote> 21650</blockquote> 21651 21652</li> 21653 21654<li> 21655 21656<p> 21657If <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1180">1180</a> is <em>not</em> accepted: 21658</p> 21659 21660<blockquote> 21661<pre>template <class BiIter, class ST, class SA> 21662 bool operator==( 21663 const basic_string< 21664 typename iterator_traits<BiIter>::value_type, ST, SA>& lhs, 21665 const sub_match<BiIter>& rhs); 21666</pre> 21667<blockquote> 216687 <i>Returns:</i> <tt><del>lhs</del><ins>basic_string<typename 21669sub_match<BiIter>::value_type>(lhs.begin(), lhs.end())</ins> == 21670rhs.str()</tt>. 21671</blockquote> 21672 21673<pre>template <class BiIter, class ST, class SA> 21674 bool operator!=( 21675 const basic_string< 21676 typename iterator_traits<BiIter>::value_type, ST, SA>& lhs, 21677 const sub_match<BiIter>& rhs); 21678</pre> 21679 21680<blockquote> 216818 <i>Returns:</i> <tt><del>lhs</del><ins>basic_string<typename 21682sub_match<BiIter>::value_type>(lhs.begin(), lhs.end())</ins> != 21683rhs.str()</tt>. 21684</blockquote> 21685 21686<pre>template <class BiIter, class ST, class SA> 21687 bool operator<( 21688 const basic_string< 21689 typename iterator_traits<BiIter>::value_type, ST, SA>& lhs, 21690 const sub_match<BiIter>& rhs); 21691</pre> 21692 21693<blockquote> 216949 <i>Returns:</i> <tt><del>lhs</del><ins>basic_string<typename 21695sub_match<BiIter>::value_type>(lhs.begin(), lhs.end())</ins> < 21696rhs.str()</tt>. 21697</blockquote> 21698 21699<pre>template <class BiIter, class ST, class SA> 21700 bool operator>( 21701 const basic_string< 21702 typename iterator_traits<BiIter>::value_type, ST, SA>& lhs, 21703 const sub_match<BiIter>& rhs); 21704</pre> 21705 21706<blockquote> 2170710 <i>Returns:</i> <tt><del>lhs</del><ins>basic_string<typename 21708sub_match<BiIter>::value_type>(lhs.begin(), lhs.end())</ins> > 21709rhs.str()</tt>. 21710</blockquote> 21711 21712<pre>template <class BiIter, class ST, class SA> 21713 bool operator>=( 21714 const basic_string< 21715 typename iterator_traits<BiIter>::value_type, ST, SA>& lhs, 21716 const sub_match<BiIter>& rhs); 21717</pre> 21718 21719<blockquote> 2172011 <i>Returns:</i> <tt><del>lhs</del><ins>basic_string<typename 21721sub_match<BiIter>::value_type>(lhs.begin(), lhs.end())</ins> >= 21722rhs.str()</tt>. 21723</blockquote> 21724 21725<pre>template <class BiIter, class ST, class SA> 21726 bool operator<=( 21727 const basic_string< 21728 typename iterator_traits<BiIter>::value_type, ST, SA>& lhs, 21729 const sub_match<BiIter>& rhs); 21730</pre> 21731 21732<blockquote> 2173312 <i>Returns:</i> <tt><del>lhs</del><ins>basic_string<typename 21734sub_match<BiIter>::value_type>(lhs.begin(), lhs.end())</ins> <= 21735rhs.str()</tt>. 21736</blockquote> 21737 21738<pre>template <class BiIter, class ST, class SA> 21739 bool operator==(const sub_match<BiIter>& lhs, 21740 const basic_string< 21741 typename iterator_traits<BiIter>::value_type, ST, SA>& rhs); 21742</pre> 21743 21744<blockquote> 2174513 <i>Returns:</i> <tt>lhs.str() == <del>rhs</del><ins>basic_string<typename 21746sub_match<BiIter>::value_type>(rhs.begin(), rhs.end())</ins></tt>. 21747</blockquote> 21748 21749<pre>template <class BiIter, class ST, class SA> 21750 bool operator!=(const sub_match<BiIter>& lhs, 21751 const basic_string< 21752 typename iterator_traits<BiIter>::value_type, ST, SA>& rhs); 21753</pre> 21754 21755<blockquote> 2175614 <i>Returns:</i> <tt>lhs.str() != <del>rhs</del><ins>basic_string<typename 21757sub_match<BiIter>::value_type>(rhs.begin(), rhs.end())</ins></tt>. 21758</blockquote> 21759 21760<pre>template <class BiIter, class ST, class SA> 21761 bool operator<(const sub_match<BiIter>& lhs, 21762 const basic_string< 21763 typename iterator_traits<BiIter>::value_type, ST, SA>& rhs); 21764</pre> 21765 21766<blockquote> 2176715 <i>Returns:</i> <tt>lhs.str() < <del>rhs</del><ins>basic_string<typename 21768sub_match<BiIter>::value_type>(rhs.begin(), rhs.end())</ins></tt>. 21769</blockquote> 21770 21771<pre>template <class BiIter, class ST, class SA> 21772 bool operator>(const sub_match<BiIter>& lhs, 21773 const basic_string< 21774 typename iterator_traits<BiIter>::value_type, ST, SA>& rhs); 21775</pre> 21776 21777<blockquote> 2177816 <i>Returns:</i> <tt>lhs.str() > <del>rhs</del><ins>basic_string<typename 21779sub_match<BiIter>::value_type>(rhs.begin(), rhs.end())</ins></tt>. 21780</blockquote> 21781 21782<pre>template <class BiIter, class ST, class SA> 21783 bool operator>=(const sub_match<BiIter>& lhs, 21784 const basic_string< 21785 typename iterator_traits<BiIter>::value_type, ST, SA>& rhs); 21786</pre> 21787 21788<blockquote> 2178917 <i>Returns:</i> <tt>lhs.str() >= <del>rhs</del><ins>basic_string<typename 21790sub_match<BiIter>::value_type>(rhs.begin(), rhs.end())</ins></tt>. 21791</blockquote> 21792 21793<pre>template <class BiIter, class ST, class SA> 21794 bool operator<=(const sub_match<BiIter>& lhs, 21795 const basic_string< 21796 typename iterator_traits<BiIter>::value_type, ST, SA>& rhs); 21797</pre> 21798 21799<blockquote> 2180018 <i>Returns:</i> <tt>lhs.str() <= <del>rhs</del><ins>basic_string<typename 21801sub_match<BiIter>::value_type>(rhs.begin(), rhs.end())</ins></tt>. 21802</blockquote> 21803</blockquote> 21804 21805</li> 21806 21807</ol> 21808 21809</li> 21810</ol> 21811 21812 21813 21814 21815 21816<hr> 21817<h3><a name="1182"></a>1182. Unfortunate hash dependencies</h3> 21818<p><b>Section:</b> 20.7.16 [unord.hash] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 21819 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-07-28 <b>Last modified:</b> 2009-09-21</p> 21820<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#unord.hash">active issues</a> in [unord.hash].</p> 21821<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#unord.hash">issues</a> in [unord.hash].</p> 21822<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 21823<p><b>Discussion:</b></p> 21824<p> 21825The implied library dependencies created by spelling out all the <tt>hash</tt> 21826template specializations in the <tt><functional></tt> synopsis are unfortunate. 21827The potential coupling is greatly reduced if the <tt>hash</tt> specialization is 21828declared in the appropriate header for each library type, as it is much 21829simpler to forward declare the primary template and provide a single 21830specialization than it is to implement a <tt>hash</tt> function for a <tt>string</tt> or 21831<tt>vector</tt> without providing a definition for the whole <tt>string/vector</tt> 21832template in order to access the necessary bits. 21833</p> 21834 21835<p> 21836Note that the proposed resolution purely involves moving the 21837declarations of a few specializations, it specifically does not make any 21838changes to 20.7.16 [unord.hash]. 21839</p> 21840 21841<p><i>[ 218422009-09-15 Daniel adds: 21843]</i></p> 21844 21845 21846<blockquote> 21847</blockquote> 21848<p> 21849I suggest to add to the current existing 21850proposed resolution the following items. 21851</p> 21852 21853<ul> 21854<li> 21855<p> 21856Add to the very first strike-list of the currently suggested resolution 21857the following lines: 21858</p> 21859 21860<blockquote><pre><del>template <> struct hash<std::error_code>;</del> 21861<del>template <> struct hash<std::thread::id>;</del> 21862</pre></blockquote> 21863</li> 21864 21865<li> 21866<p> 21867Add the following declarations to 19.5 [syserr], header 21868<tt><system_error></tt> synopsis after // 19.5.4: 21869</p> 21870 21871<blockquote><pre><ins> 21872// 19.5.x hash support 21873template <class T> struct hash; 21874template <> struct hash<error_code>; 21875</ins> 21876</pre></blockquote> 21877</li> 21878 21879<li> 21880<p> 21881Add a new clause 19.5.X (probably after 19.5.4): 21882</p> 21883 21884<blockquote> 21885<p><ins> 2188619.5.X Hash support [syserr.hash] 21887</ins></p> 21888 21889<pre><ins> 21890template <> struct hash<error_code>; 21891</ins></pre> 21892 21893<blockquote><ins> 21894An explicit specialization of the class template hash (20.7.16 [unord.hash]) 21895shall be provided 21896for the type <tt>error_code</tt> suitable for using this type as key in 21897unordered associative 21898containers (23.5 [unord]). 21899</ins></blockquote> 21900</blockquote> 21901</li> 21902 21903<li> 21904<p> 21905Add the following declarations to 30.3.1.1 [thread.thread.id] just after the 21906declaration of 21907the comparison operators: 21908</p> 21909 21910<blockquote><pre><ins> 21911template <class T> struct hash; 21912template <> struct hash<thread::id>; 21913</ins></pre></blockquote> 21914</li> 21915 21916<li> 21917<p> 21918Add a new paragraph at the end of 30.3.1.1 [thread.thread.id]: 21919</p> 21920 21921<blockquote> 21922<pre><ins> 21923template <> struct hash<thread::id>; 21924</ins></pre> 21925 21926<blockquote><ins> 21927An explicit specialization of the class template hash (20.7.16 [unord.hash]) 21928shall be provided 21929for the type <tt>thread::id</tt> suitable for using this type as key in 21930unordered associative 21931containers (23.5 [unord]). 21932</ins></blockquote> 21933</blockquote> 21934</li> 21935 21936<li> 21937Issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#889">889</a> independently suggests moving the specialization 21938<tt>std::hash<std::thread::id></tt> to header <tt><thread></tt>. 21939</li> 21940</ul> 21941 21942 21943 21944<p><b>Proposed resolution:</b></p> 21945<p> 21946Strike the following specializations declared in the <tt><functional></tt> 21947synopsis p2 20.7 [function.objects] 21948</p> 21949 21950<blockquote><pre><del>template <> struct hash<std::string>;</del> 21951<del>template <> struct hash<std::u16string>;</del> 21952<del>template <> struct hash<std::u32string>;</del> 21953<del>template <> struct hash<std::wstring>;</del> 21954 21955<del>template <class Allocator> struct hash<std::vector<bool, Allocator> >;</del> 21956<del>template <std::size_t N> struct hash<std::bitset<N> >;</del> 21957</pre></blockquote> 21958 21959<p> 21960Add the following declarations to the synopsis of <tt><string></tt> in 2196121.3 [string.classes] 21962</p> 21963 21964<blockquote><pre><ins>// 21.4.x hash support 21965template <class T> struct hash; 21966template <> struct hash<string>; 21967template <> struct hash<u16string>; 21968template <> struct hash<u32string>; 21969template <> struct hash<wstring>;</ins> 21970</pre></blockquote> 21971 21972<p> 21973Add a new clause 21.4.X 21974</p> 21975 21976<blockquote> 21977<p> 2197821.4.X Hash support [basic.string.hash] 21979</p> 21980 21981<pre>template <> struct hash<string>; 21982template <> struct hash<u16string>; 21983template <> struct hash<u32string>; 21984template <> struct hash<wstring>; 21985</pre> 21986 21987<blockquote> 21988Explicit specializations of the class template hash (20.7.16 [unord.hash]) 21989shall be provided for the types <tt>string</tt>, <tt>u16string</tt>, 21990<tt>u32string</tt> and <tt>wstring</tt> suitable for using these types as keys in 21991unordered associative containers (23.5 [unord]). 21992</blockquote> 21993</blockquote> 21994 21995<p> 21996Add the following declarations to the synopsis of <tt><vector></tt> in 2199723.3 [sequences] 21998</p> 21999 22000<blockquote><pre><ins> 22001// 21.4.x hash support 22002template <class T> struct hash; 22003template <class Allocator> struct hash<vector<bool, Allocator>>; 22004</ins></pre></blockquote> 22005 22006<p> 22007Add a new paragraph to the end of 23.3.7 [vector.bool] 22008</p> 22009 22010<blockquote><pre>template <class Allocator> struct hash<vector<bool, Allocator>>; 22011</pre> 22012<blockquote> 22013A partial specialization of the class template hash (20.7.16 [unord.hash]) 22014shall be provided for vectors of boolean values suitable for use as a key 22015in unordered associative containers (23.5 [unord]). 22016</blockquote> 22017</blockquote> 22018 22019<p> 22020Add the following declarations to the synopsis of <tt><bitset></tt> 22021in 20.3.7 [template.bitset] 22022</p> 22023 22024<blockquote><pre><ins> 22025// 20.3.6.X hash support 22026template <class T> struct hash; 22027template <size_t N> struct hash<bitset<N> >; 22028</ins></pre></blockquote> 22029 22030<p> 22031Add a new subclause 20.3.6.X [bitset.hash] 22032</p> 22033 22034<blockquote> 22035<p> 2203620.3.6.X bitset hash support [bitset.hash] 22037</p> 22038 22039<pre>template <size_t N> struct hash<bitset<N> >; 22040</pre> 22041 22042<blockquote> 22043A partial specialization of the class template hash 22044(20.7.16 [unord.hash]) shall be provided for bitsets suitable for use as a key in 22045unordered associative containers (23.5 [unord]). 22046</blockquote> 22047</blockquote> 22048 22049 22050 22051 22052 22053 22054<hr> 22055<h3><a name="1183"></a>1183. <tt>basic_ios::set_rdbuf</tt> may break class invariants</h3> 22056<p><b>Section:</b> 27.5.4.2 [basic.ios.members] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 22057 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2009-07-28 <b>Last modified:</b> 2009-10-22</p> 22058<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#basic.ios.members">active issues</a> in [basic.ios.members].</p> 22059<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#basic.ios.members">issues</a> in [basic.ios.members].</p> 22060<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 22061<p><b>Discussion:</b></p> 22062<p> 22063The protected member function <tt>set_rdbuf</tt> had been added during the 22064process of adding move and swap semantics to IO classes. A relevant 22065property of this function is described by it's effects in 2206627.5.4.2 [basic.ios.members]/19: 22067</p> 22068 22069<blockquote> 22070<i>Effects:</i> Associates the <tt>basic_streambuf</tt> object pointed to by sb with 22071this stream without calling <tt>clear()</tt>. 22072</blockquote> 22073 22074<p> 22075This means that implementors of or those who derive from existing IO classes 22076could cause an internal state where the stream buffer could be 0, but the 22077IO class has the state <tt>good()</tt>. This would break several currently existing 22078implementations which rely on the fact that setting a stream buffer via the 22079currently only ways, i.e. either by calling 22080</p> 22081 22082<blockquote><pre>void init(basic_streambuf<charT,traits>* sb); 22083</pre></blockquote> 22084 22085<p> 22086or by calling 22087</p> 22088 22089<blockquote><pre>basic_streambuf<charT,traits>* rdbuf(basic_streambuf<charT,traits>* sb); 22090</pre></blockquote> 22091 22092<p> 22093to set <tt>rdstate()</tt> to <tt>badbit</tt>, if the buffer is 0. This has the effect that many 22094internal functions can simply check <tt>rdstate()</tt> instead of <tt>rdbuf()</tt> for being 0. 22095</p> 22096 22097<p> 22098I therefore suggest that a requirement is added for callers of <tt>set_rdbuf</tt> to 22099set a non-0 value. 22100</p> 22101 22102<p><i>[ 221032009-10 Santa Cruz: 22104]</i></p> 22105 22106 22107<blockquote> 22108Moved to Open. Martin volunteers to provide new wording, where 22109<tt>set_rdbuf()</tt> sets the <tt>badbit</tt> but does not cause an 22110exception to be thrown like a call to <tt>clear()</tt> would. 22111</blockquote> 22112 22113<p><i>[ 221142009-10-20 Martin provides wording: 22115]</i></p> 22116 22117 22118 22119 22120<p><b>Proposed resolution:</b></p> 22121<p> 22122Change 27.5.4.2 [basic.ios.members] around p. 19 as indicated: 22123</p> 22124 22125<blockquote><pre>void set_rdbuf(basic_streambuf<charT, traits>* sb); 22126</pre> 22127 22128<blockquote> 22129<p><del> 22130<i>Effects:</i> Associates the <tt>basic_streambuf</tt> object pointed 22131to by <tt>sb</tt> with this stream without calling <tt>clear()</tt>. 22132<i>Postconditions:</i> <tt>rdbuf() == sb</tt>. 22133</del></p> 22134 22135<p><ins> 22136<i>Effects:</i> As if: 22137</ins></p> 22138 22139<blockquote><pre><ins> 22140iostate state = rdstate(); 22141try { rdbuf(sb); } 22142catch(ios_base::failure) { 22143 if (0 == (state & ios_base::badbit)) 22144 unsetf(badbit); 22145} 22146</ins></pre></blockquote> 22147 22148<p> 22149<i>Throws:</i> Nothing. 22150</p> 22151 22152</blockquote> 22153</blockquote> 22154 22155 22156<p><b>Rationale:</b></p> 22157We need to be able to call <tt>set_rdbuf()</tt> on stream objects 22158for which (<tt>rdbuf() == 0</tt>) holds without causing <tt>ios_base::failure</tt> to 22159be thrown. We also don't want <tt>badbit</tt> to be set as a result of 22160setting <tt>rdbuf()</tt> to 0 if it wasn't set before the call. This changed 22161Effects clause maintains the current behavior (as of N2914) without 22162requiring that <tt>sb</tt> be non-null. 22163 22164 22165 22166 22167 22168<hr> 22169<h3><a name="1185"></a>1185. iterator categories and output iterators</h3> 22170<p><b>Section:</b> 24.2 [iterator.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 22171 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-07-31 <b>Last modified:</b> 2009-07-31</p> 22172<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#iterator.requirements">active issues</a> in [iterator.requirements].</p> 22173<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#iterator.requirements">issues</a> in [iterator.requirements].</p> 22174<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 22175<p><b>Discussion:</b></p> 22176<p> 22177(wording relative to 22178<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2723.pdf">N2723</a> 22179pending new working paper) 22180</p> 22181 22182<p> 22183According to p3 24.2 [iterator.requirements], Forward iterators, 22184Bidirectional iterators and Random Access iterators all satisfy the 22185requirements for an Output iterator: 22186</p> 22187 22188<blockquote> 22189XXX iterators satisfy all the requirements of the input and output iterators 22190and can be used whenever either kind is specified ... 22191</blockquote> 22192 22193<p> 22194Meanwhile, p4 goes on to contradict this: 22195</p> 22196 22197<blockquote> 22198Besides its category, a forward, bidirectional, or random access 22199iterator can also be mutable or constant... 22200</blockquote> 22201 22202<blockquote> 22203... Constant iterators do not satisfy the requirements for output iterators 22204</blockquote> 22205 22206<p> 22207The latter seems to be the overriding concern, as the iterator tag 22208hierarchy does not define <tt>forward_iterator_tag</tt> as multiply derived from 22209both <tt>input_iterator_tag</tt> and <tt>output_iterator_tag</tt>. 22210</p> 22211 22212<p> 22213The work on concepts for iterators showed us that output iterator really 22214is fundamentally a second dimension to the iterator categories, rather 22215than part of the linear input -> forward -> bidirectional -> 22216random-access sequence. It would be good to clear up these words to 22217reflect that, and separately list output iterator requirements in the 22218requires clauses for the appropriate algorithms and operations. 22219</p> 22220 22221 22222<p><b>Proposed resolution:</b></p> 22223 22224 22225 22226 22227 22228<hr> 22229<h3><a name="1186"></a>1186. Forward list could model a stack</h3> 22230<p><b>Section:</b> 23.3.5.3 [stack] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Concepts">Tentatively NAD Concepts</a> 22231 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-07-31 <b>Last modified:</b> 2009-11-02</p> 22232<p><b>Discussion:</b></p> 22233<p> 22234The library template <tt>forward_list</tt> could easily model the idea of a 22235<tt>stack</tt>, where the operations work on the front of the list rather than 22236the back. However, the standard library <tt>stack</tt> adaptor cannot support 22237this. 22238</p> 22239 22240<p> 22241It would be relatively easy to write a partial specialization for <tt>stack</tt> 22242to support <tt>forward_list</tt>, but that opens the question of which header to 22243place it in. A much better solution would be to add a <tt>concept_map</tt> for 22244the <tt>StackLikeContainer</tt> concept to the <tt><forward_list></tt> header and then 22245everything just works, including a user's own further uses in a 22246stack-like context. 22247</p> 22248 22249<p> 22250Therefore while I am submitting the issue now so that it is on record, I 22251<em>strongly recommend</em> we resolve as "NAD Concepts" as any non-concepts 22252based solution will be inferior to the final goal, and the feature is 22253not so compelling it must be supported ahead of the concepts-based 22254library. 22255</p> 22256 22257<p><i>[ 222582009-11-02 Howard adds: 22259]</i></p> 22260 22261 22262<blockquote> 22263Moved to Tentatively NAD Concepts after 5 positive votes on c++std-lib. 22264</blockquote> 22265 22266 22267<p><b>Proposed resolution:</b></p> 22268 22269 22270 22271 22272 22273<hr> 22274<h3><a name="1187"></a>1187. std::decay</h3> 22275<p><b>Section:</b> 20.6.7 [meta.trans.other] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 22276 <b>Submitter:</b> Jason Merrill <b>Opened:</b> 2009-08-07 <b>Last modified:</b> 2009-08-22</p> 22277<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#meta.trans.other">issues</a> in [meta.trans.other].</p> 22278<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 22279<p><b>Discussion:</b></p> 22280<p> 22281I notice that <tt>std::decay</tt> is specified to strip the cv-quals from 22282anything but an array or pointer. This seems incorrect for values of 22283class type, since class rvalues can have cv-qualified type (3.10 [basic.lval]/9). 22284</p> 22285 22286<p><i>[ 222872009-08-09 Howard adds: 22288]</i></p> 22289 22290 22291<blockquote> 22292See the thread starting with c++std-lib-24568 for further discussion. And 22293here is a convenience link to the 22294<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2006/n2069.html">original proposal</a>. 22295Also see the closely related issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#705">705</a>. 22296</blockquote> 22297 22298 22299<p><b>Proposed resolution:</b></p> 22300 22301<p> 22302Add a note to <tt>decay</tt> in 20.6.7 [meta.trans.other]: 22303</p> 22304 22305<blockquote> 22306[<i>Note:</i> This behavior is similar to the lvalue-to-rvalue (4.1), 22307array-to-pointer (4.2), and function-to-pointer (4.3) conversions 22308applied when an lvalue expression is used as an rvalue, but also strips 22309cv-qualifiers from class types in order to more closely model by-value 22310argument passing. — <i>end note</i>] 22311</blockquote> 22312 22313 22314 22315 22316 22317 22318 22319 22320<hr> 22321<h3><a name="1188"></a>1188. Unordered containers should have a minimum load factor as well as a maximum</h3> 22322<p><b>Section:</b> 23.2.5 [unord.req], 23.5 [unord] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 22323 <b>Submitter:</b> Matt Austern <b>Opened:</b> 2009-08-10 <b>Last modified:</b> 2009-08-11</p> 22324<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#unord.req">active issues</a> in [unord.req].</p> 22325<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#unord.req">issues</a> in [unord.req].</p> 22326<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 22327<p><b>Discussion:</b></p> 22328<p> 22329Unordered associative containers have a notion of a maximum load factor: 22330when the number of elements grows large enough, the containers 22331automatically perform a rehash so that the number of elements per bucket 22332stays below a user-specified bound. This ensures that the hash table's 22333performance characteristics don't change dramatically as the size 22334increases. 22335</p> 22336 22337<p> 22338For similar reasons, Google has found it useful to specify a minimum 22339load factor: when the number of elements shrinks by a large enough, the 22340containers automatically perform a rehash so that the number of elements 22341per bucket stays above a user-specified bound. This is useful for two 22342reasons. First, it prevents wasting a lot of memory when an unordered 22343associative container grows temporarily. Second, it prevents amortized 22344iteration time from being arbitrarily large; consider the case of a hash 22345table with a billion buckets and only one element. (This was discussed 22346even before TR1 was published; it was TR issue 6.13, which the LWG 22347closed as NAD on the grounds that it was a known design feature. 22348However, the LWG did not consider the approach of a minimum load 22349factor.) 22350</p> 22351 22352<p> 22353The only interesting question is when shrinking is allowed. In principle 22354the cleanest solution would be shrinking on erase, just as we grow on 22355insert. However, that would be a usability problem; it would break a 22356number of common idioms involving erase. Instead, Google's hash tables 22357only shrink on insert and rehash. 22358</p> 22359 22360<p> 22361The proposed resolution allows, but does not require, shrinking in 22362rehash, mostly because a postcondition for rehash that involves the 22363minimum load factor would be fairly complicated. (It would probably have 22364to involve a number of special cases and it would probably have to 22365mention yet another parameter, a minimum bucket count.) 22366</p> 22367 22368<p> 22369The current behavior is equivalent to a minimum load factor of 0. If we 22370specify that 0 is the default, this change will have no impact on 22371backward compatibility. 22372</p> 22373 22374 22375<p><b>Proposed resolution:</b></p> 22376<p> 22377Add two new rows, and change rehash's postcondition in the unordered 22378associative container requirements table in 23.2.5 [unord.req]: 22379</p> 22380 22381<blockquote> 22382<table border="1"> 22383<caption>Table 87 — Unordered associative container requirements 22384(in addition to container)</caption> 22385 22386<tbody><tr> 22387<th>Expression</th><th>Return type</th><th>Assertion/note pre-/post-condition</th> 22388<th>Complexity</th> 22389</tr> 22390<tr> 22391<td><ins> 22392<tt>a.min_load_factor()</tt> 22393</ins></td> 22394<td><ins> 22395<tt>float</tt> 22396</ins></td> 22397<td><ins> 22398Returns a non-negative number that the container attempts to keep the 22399load factor greater than or equal to. The container automatically 22400decreases the number of buckets as necessary to keep the load factor 22401above this number. 22402</ins></td> 22403<td><ins> 22404constant 22405</ins></td> 22406</tr> 22407 22408<tr> 22409<td><ins><tt>a.min_load_factor(z)</tt></ins></td> 22410<td><ins><tt>void</tt></ins></td> 22411<td><ins>Pre: <tt>z</tt> shall be non-negative. Changes the container's minimum 22412load factor, using <tt>z</tt> as a hint. [<i>Footnote:</i> the minimum 22413load factor should be significantly smaller than the maximum. 22414If <tt>z</tt> is too large, the implementation may reduce it to a more sensible value.] 22415</ins></td> 22416<td><ins> 22417constant 22418</ins></td> 22419</tr> 22420<tr> 22421<td><tt>a.rehash(n)</tt></td> 22422<td><tt>void</tt></td> 22423<td> 22424Post: <ins><tt>a.bucket_count() >= n</tt>, and <tt>a.size() <= a.bucket_count() 22425* a.max_load_factor()</tt>. [<i>Footnote:</i> It is intentional that the 22426postcondition does not mention the minimum load factor. 22427This member function is primarily intended for cases where the user knows 22428that the container's size will increase soon, in which case the container's 22429load factor will temporarily fall below <tt>a.min_load_factor()</tt>.]</ins> 22430<del> 22431<tt>a.bucket_cout > a.size() / a.max_load_factor()</tt> and <tt>a.bucket_count() 22432>= n</tt>. 22433</del> 22434</td> 22435<td> 22436Average case linear in <tt>a.size()</tt>, worst case quadratic. 22437</td> 22438</tr> 22439</tbody></table> 22440</blockquote> 22441 22442<p> 22443Add a footnote to 23.2.5 [unord.req] p12: 22444</p> 22445 22446<blockquote> 22447<p> 22448The insert members shall not affect the validity of references to 22449container elements, but may invalidate all iterators to the container. 22450The erase members shall invalidate only iterators and references to the 22451erased elements. 22452</p> 22453 22454<blockquote><ins> 22455[A consequence of these requirements is that while insert may change the 22456number of buckets, erase may not. The number of buckets may be reduced 22457on calls to insert or rehash.] 22458</ins></blockquote> 22459</blockquote> 22460 22461<p> 22462Change paragraph 13: 22463</p> 22464 22465<blockquote> 22466The insert members shall not affect the validity of iterators if 22467<del><tt>(N+n) < z * B</tt></del> <ins><tt>zmin * B <= (N+n) <= zmax * B</tt></ins>, 22468where <tt>N</tt> is the number of elements in 22469the container prior to the insert operation, <tt>n</tt> is the number of 22470elements inserted, <tt>B</tt> is the container's bucket count, 22471<ins><tt>zmin</tt> is the container's minimum load factor,</ins> 22472and <tt>z<ins>max</ins></tt> is the container's maximum load factor. 22473</blockquote> 22474 22475<p> 22476Add to the <tt>unordered_map</tt> class synopsis in section 23.5.1 [unord.map], 22477the <tt>unordered_multimap</tt> class synopsis 22478in 23.5.2 [unord.multimap], the <tt>unordered_set</tt> class synopsis in 2247923.5.3 [unord.set], and the <tt>unordered_multiset</tt> class synopsis 22480in 23.5.4 [unord.multiset]: 22481</p> 22482 22483<blockquote><pre><ins> 22484float min_load_factor() const; 22485void min_load_factor(float z); 22486</ins></pre></blockquote> 22487 22488<p> 22489In 23.5.1.1 [unord.map.cnstr], 23.5.2.1 [unord.multimap.cnstr], 23.5.3.1 [unord.set.cnstr], and 2249023.5.4.1 [unord.multiset.cnstr], change: 22491</p> 22492 22493<blockquote> 22494... <tt>max_load_factor()</tt> returns 1.0 <ins>and 22495<tt>min_load_factor()</tt> returns 0</ins>. 22496</blockquote> 22497 22498 22499 22500 22501 22502<hr> 22503<h3><a name="1189"></a>1189. Awkward interface for changing the number of buckets in an unordered associative container</h3> 22504<p><b>Section:</b> 23.2.5 [unord.req], 23.5 [unord] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Tentatively Ready</a> 22505 <b>Submitter:</b> Matt Austern <b>Opened:</b> 2009-08-10 <b>Last modified:</b> 2009-10-28</p> 22506<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#unord.req">active issues</a> in [unord.req].</p> 22507<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#unord.req">issues</a> in [unord.req].</p> 22508<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20Ready">Tentatively Ready</a> status.</p> 22509<p><b>Discussion:</b></p> 22510<p> 22511Consider a typical use case: I create an <tt>unordered_map</tt> and then start 22512adding elements to it one at a time. I know that it will eventually need 22513to store a few million elements, so, for performance reasons, I would 22514like to reserve enough capacity that none of the calls to <tt>insert</tt> will 22515trigger a rehash. 22516</p> 22517 22518<p> 22519Unfortunately, the existing interface makes this awkward. The user 22520naturally sees the problem in terms of the number of elements, but the 22521interface presents it as buckets. If <tt>m</tt> is the map and <tt>n</tt> is the expected 22522number of elements, this operation is written <tt>m.rehash(n / 22523m.max_load_factor())</tt> — not very novice friendly. 22524</p> 22525 22526<p><i>[ 225272009-09-30 Daniel adds: 22528]</i></p> 22529 22530 22531<blockquote> 22532I recommend to replace "<tt>resize</tt>" by a different name like 22533"<tt>reserve</tt>", because that would better match the intended 22534use-case. Rational: Any existing resize function has the on-success 22535post-condition that the provided size is equal to <tt>size()</tt>, which 22536is not satisfied for the proposal. Reserve seems to fit the purpose of 22537the actual renaming suggestion. 22538</blockquote> 22539 22540<p><i>[ 225412009-10-28 Ganesh summarizes alternative resolutions and expresses a 22542strong preference for the second (and opposition to the first): 22543]</i></p> 22544 22545 22546<blockquote> 22547<ol> 22548<li> 22549<p> 22550In the unordered associative container requirements (23.2.5 [unord.req]), 22551remove the row for 22552rehash and replace it with: 22553</p> 22554 22555<blockquote> 22556<table border="1"> 22557<caption>Table 87 — Unordered associative container requirements 22558(in addition to container)</caption> 22559 22560<tbody><tr> 22561<th>Expression</th><th>Return type</th><th>Assertion/note pre-/post-condition</th> 22562<th>Complexity</th> 22563</tr> 22564<tr> 22565<td><tt>a.<del>rehash</del><ins>reserve</ins>(n)</tt></td> 22566<td><tt>void</tt></td> 22567<td> 22568Post: <tt>a.bucket_count > <ins>max(</ins>a.size()<ins>, n)</ins> 22569/ a.max_load_factor()</tt><del> and <tt>a.bucket_count() 22570>= n</tt></del>. 22571</td> 22572<td> 22573Average case linear in <tt>a.size()</tt>, worst case quadratic. 22574</td> 22575</tr> 22576</tbody></table> 22577</blockquote> 22578 22579<p> 22580Make the corresponding change in the class synopses in 23.5.1 22581[unord.map], 23.5.2 [unord.multimap], 23.5.3 [unord.set], and 23.5.4 22582[unord.multiset]. 22583</p> 22584</li> 22585<li> 22586 22587<p> 22588In 23.2.5 [unord.req]/9, table 98, append a new row after the last one: 22589</p> 22590 22591<blockquote> 22592<table border="1"> 22593<caption>Table 87 — Unordered associative container requirements 22594(in addition to container)</caption> 22595 22596<tbody><tr> 22597<th>Expression</th><th>Return type</th><th>Assertion/note pre-/post-condition</th> 22598<th>Complexity</th> 22599</tr> 22600<tr> 22601<td><tt>a.rehash(n)</tt></td> 22602<td><tt>void</tt></td> 22603<td> 22604Post: <tt>a.bucket_count > a.size() 22605/ a.max_load_factor()</tt> and <tt>a.bucket_count() 22606>= n</tt>. 22607</td> 22608<td> 22609Average case linear in <tt>a.size()</tt>, worst case quadratic. 22610</td> 22611</tr> 22612<tr> 22613<td><ins> 22614<tt>a.reserve(n)</tt> 22615</ins></td> 22616<td><ins> 22617<tt>void</tt> 22618</ins></td> 22619<td><ins> 22620Same as <tt>a.rehash(ceil(n / a.max_load_factor()))</tt> 22621</ins></td> 22622<td><ins> 22623Average case linear in <tt>a.size()</tt>, worst case quadratic. 22624</ins></td> 22625</tr> 22626</tbody></table> 22627</blockquote> 22628 22629<p> 22630In 23.5.1 [unord.map]/3 in the definition of class template <tt>unordered_map</tt>, in 2263123.5.2 [unord.multimap]/3 in the definition of class template <tt>unordered_multimap</tt>, in 2263223.5.3 [unord.set]/3 in the definition of class template <tt>unordered_set</tt> and in 2263323.5.4 [unord.multiset]/3 in the definition of class template <tt>unordered_multiset</tt>, add the 22634following line after member function <tt>rehash()</tt>: 22635</p> 22636 22637<blockquote><pre>void reserve(size_type n); 22638</pre></blockquote> 22639 22640</li> 22641</ol> 22642</blockquote> 22643 22644<p><i>[ 226452009-10-28 Howard: 22646]</i></p> 22647 22648 22649<blockquote> 22650<p> 22651Moved to Tentatively Ready after 5 votes in favor of Ganesh's option 2 above. 22652The original proposed wording now appears here: 22653</p> 22654 22655<blockquote> 22656<p> 22657Informally: instead of providing <tt>rehash(n)</tt> provide <tt>resize(n)</tt>, with the 22658semantics "make the container a good size for <tt>n</tt> elements". 22659</p> 22660 22661<p> 22662In the unordered associative container requirements (23.2.5 [unord.req]), 22663remove the row for 22664rehash and replace it with: 22665</p> 22666 22667<blockquote> 22668<table border="1"> 22669<caption>Table 87 — Unordered associative container requirements 22670(in addition to container)</caption> 22671 22672<tbody><tr> 22673<th>Expression</th><th>Return type</th><th>Assertion/note pre-/post-condition</th> 22674<th>Complexity</th> 22675</tr> 22676<tr> 22677<td><tt>a.<del>rehash</del><ins>resize</ins>(n)</tt></td> 22678<td><tt>void</tt></td> 22679<td> 22680Post: <tt>a.bucket_count > <ins>max(</ins>a.size()<ins>, n)</ins> 22681/ a.max_load_factor()</tt><del> and <tt>a.bucket_count() 22682>= n</tt></del>. 22683</td> 22684<td> 22685Average case linear in <tt>a.size()</tt>, worst case quadratic. 22686</td> 22687</tr> 22688</tbody></table> 22689</blockquote> 22690 22691<p>Make the corresponding change in the class synopses in 23.5.1 22692[unord.map], 23.5.2 [unord.multimap], 23.5.3 [unord.set], and 23.5.4 22693[unord.multiset]. 22694</p> 22695 22696</blockquote> 22697</blockquote> 22698 22699 22700<p><b>Proposed resolution:</b></p> 22701<p> 22702In 23.2.5 [unord.req]/9, table 98, append a new row after the last one: 22703</p> 22704 22705<blockquote> 22706<table border="1"> 22707<caption>Table 87 — Unordered associative container requirements 22708(in addition to container)</caption> 22709 22710<tbody><tr> 22711<th>Expression</th><th>Return type</th><th>Assertion/note pre-/post-condition</th> 22712<th>Complexity</th> 22713</tr> 22714<tr> 22715<td><tt>a.rehash(n)</tt></td> 22716<td><tt>void</tt></td> 22717<td> 22718Post: <tt>a.bucket_count > a.size() 22719/ a.max_load_factor()</tt> and <tt>a.bucket_count() 22720>= n</tt>. 22721</td> 22722<td> 22723Average case linear in <tt>a.size()</tt>, worst case quadratic. 22724</td> 22725</tr> 22726<tr> 22727<td><ins> 22728<tt>a.reserve(n)</tt> 22729</ins></td> 22730<td><ins> 22731<tt>void</tt> 22732</ins></td> 22733<td><ins> 22734Same as <tt>a.rehash(ceil(n / a.max_load_factor()))</tt> 22735</ins></td> 22736<td><ins> 22737Average case linear in <tt>a.size()</tt>, worst case quadratic. 22738</ins></td> 22739</tr> 22740</tbody></table> 22741</blockquote> 22742 22743<p> 22744In 23.5.1 [unord.map]/3 in the definition of class template <tt>unordered_map</tt>, in 2274523.5.2 [unord.multimap]/3 in the definition of class template <tt>unordered_multimap</tt>, in 2274623.5.3 [unord.set]/3 in the definition of class template <tt>unordered_set</tt> and in 2274723.5.4 [unord.multiset]/3 in the definition of class template <tt>unordered_multiset</tt>, add the 22748following line after member function <tt>rehash()</tt>: 22749</p> 22750 22751<blockquote><pre>void reserve(size_type n); 22752</pre></blockquote> 22753 22754 22755 22756 22757 22758<hr> 22759<h3><a name="1190"></a>1190. Setting the maximum load factor should return the previous value</h3> 22760<p><b>Section:</b> 23.2.5 [unord.req], 23.5 [unord] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 22761 <b>Submitter:</b> Matt Austern <b>Opened:</b> 2009-08-10 <b>Last modified:</b> 2009-08-11</p> 22762<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#unord.req">active issues</a> in [unord.req].</p> 22763<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#unord.req">issues</a> in [unord.req].</p> 22764<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 22765<p><b>Discussion:</b></p> 22766<p> 22767The unordered associative container requirements table specifies that 22768<tt>a.set_max_load_factor(z)</tt> has return type <tt>void</tt>. However, there is a 22769useful piece of information to return: the previous value. Users who 22770don't need it can always ignore it. 22771</p> 22772 22773 22774<p><b>Proposed resolution:</b></p> 22775<p> 22776In the unordered associative container requirements table, change: 22777</p> 22778 22779<blockquote> 22780<table border="1"> 22781<caption>Table 87 — Unordered associative container requirements 22782(in addition to container)</caption> 22783 22784<tbody><tr> 22785<th>Expression</th><th>Return type</th><th>Assertion/note pre-/post-condition</th> 22786<th>Complexity</th> 22787</tr> 22788 22789<tr> 22790<td><tt>a.max_load_factor(z)</tt></td> 22791<td><tt><del>void</del> <ins>float</ins></tt></td> 22792<td>Pre: <tt>z</tt> shall be positive. Changes the container's maximum 22793<del>load</del> load factor, using <tt>z</tt> as a hint. 22794<ins>Returns: the previous value of 22795<tt>a.max_load_factor()</tt>.</ins> 22796</td> 22797<td> 22798constant 22799</td> 22800</tr> 22801<tr></tr> 22802</tbody></table> 22803</blockquote> 22804 22805<p> 22806Change the return type of <tt>set_max_load_factor</tt> 22807in the class synopses in 23.5.1 [unord.map], 23.5.2 [unord.multimap], 23.5.3 [unord.set], 22808and 23.5.4 [unord.multiset]. 22809</p> 22810 22811<p> 22812If issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1188">1188</a> is also accepted, make the same changes for 22813<tt>min_load_factor</tt>. 22814</p> 22815 22816 22817 22818 22819 22820<hr> 22821<h3><a name="1191"></a>1191. <tt>tuple get</tt> API should respect rvalues</h3> 22822<p><b>Section:</b> 20.5.2.6 [tuple.elem] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 22823 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-08-18 <b>Last modified:</b> 2009-10-31</p> 22824<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 22825<p><b>Discussion:</b></p> 22826<p> 22827The <tt>tuple get</tt> API should respect rvalues. This would allow for moving a 22828single element out of a <tt>tuple</tt>-like type. 22829</p> 22830 22831<p><i>[ 228322009-10-30 Alisdair adds: 22833]</i></p> 22834 22835 22836<blockquote> 22837<p> 22838The issue of rvalue overloads of get for tuple-like types was briefly 22839discussed in Santa Cruz. 22840</p> 22841 22842<p> 22843The feedback was this would be welcome, but we need full wording for the 22844other types (<tt>pair</tt> and <tt>array</tt>) before advancing. 22845</p> 22846 22847<p> 22848I suggest the issue moves to Open from New as it has been considered, 22849feedback given, and it has not (yet) been rejected as NAD. 22850</p> 22851</blockquote> 22852 22853 22854 22855<p><b>Proposed resolution:</b></p> 22856<p> 22857Add the following signature to p2 20.5.1 [tuple.general] 22858</p> 22859 22860<blockquote><pre><ins> 22861template <size_t I, class ... Types> 22862typename tuple_element<I, tuple<Types...> >::type&& get(tuple<Types...> &&); 22863</ins></pre></blockquote> 22864 22865<p> 22866And again to 20.5.2.6 [tuple.elem]. 22867</p> 22868 22869<blockquote><pre><ins> 22870template <size_t I, class ... Types> 22871typename tuple_element<I, tuple<Types...> >::type&& get(tuple<Types...>&& t); 22872</ins></pre> 22873 22874<blockquote> 22875<p><ins> 22876<i>Effects:</i> Equivalent to <tt>return std::forward<typename tuple_element<I, tuple<Types...> >::type&&>(get<I>(t));</tt> 22877</ins></p> 22878 22879 22880<p><ins> 22881[<i>Note:</i> If a <tt>T</tt> in <tt>Types</tt> is some reference type <tt>X&</tt>, 22882the return type is <tt>X&</tt>, not <tt>X&&</tt>. 22883However, if the element type is non-reference type <tt>T</tt>, 22884the return type is <tt>T&&</tt>. — <i>end note</i>] 22885</ins></p> 22886 22887</blockquote> 22888</blockquote> 22889 22890<p> 22891Add the following signature to p1 20.3 [utility] 22892</p> 22893 22894<blockquote><pre><ins> 22895template <size_t I, class T1, class T2> 22896typename tuple_element<I, pair<T1,T2> >::type&& get(pair<T1, T2>&&); 22897</ins></pre></blockquote> 22898 22899<p> 22900And to p5 20.3.5 [pair.astuple] 22901</p> 22902 22903<blockquote><pre><ins> 22904template <size_t I, class T1, class T2> 22905typename tuple_element<I, pair<T1,T2> >::type&& get(pair<T1, T2>&& p); 22906</ins></pre> 22907 22908<blockquote> 22909<p><ins> 22910<i>Returns:</i> If <tt>I == 0</tt> returns <tt>std::forward<T1&&>(p.first)</tt>; 22911if <tt>I == 1</tt> 22912returns <tt>std::forward<T2&&>(p.second)</tt>; otherwise the program is ill-formed. 22913</ins></p> 22914 22915<p><ins> 22916<i>Throws:</i> Nothing. 22917</ins></p> 22918 22919</blockquote> 22920 22921</blockquote> 22922 22923<p> 22924Add the following signature to 23.3 [sequences] <tt><array></tt> synopsis 22925</p> 22926 22927<blockquote><pre><ins>template <size_t I, class T, size_t N> 22928T&& get(array<T,N> &&); 22929</ins></pre></blockquote> 22930 22931<p> 22932And after p8 23.3.1.7 [array.tuple] 22933</p> 22934 22935<blockquote><pre><ins>template <size_t I, class T, size_t N> 22936T&& get(array<T,N> && a); 22937</ins></pre> 22938 22939<blockquote><ins> 22940<i>Effects:</i> Equivalent to <tt>return std::move(get<I>(a));</tt> 22941</ins></blockquote> 22942</blockquote> 22943 22944 22945 22946 22947 22948 22949<hr> 22950<h3><a name="1192"></a>1192. <tt>basic_string</tt> missing definitions for <tt>cbegin</tt> / <tt>cend</tt> / <tt>crbegin</tt> / <tt>crend</tt></h3> 22951<p><b>Section:</b> 21.4.3 [string.iterators] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Tentatively Ready</a> 22952 <b>Submitter:</b> Jonathan Wakely <b>Opened:</b> 2009-08-14 <b>Last modified:</b> 2009-10-29</p> 22953<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20Ready">Tentatively Ready</a> status.</p> 22954<p><b>Discussion:</b></p> 22955<p> 22956Unlike the containers in clause 23, <tt>basic_string</tt> has definitions for 22957<tt>begin()</tt> and <tt>end()</tt>, but these have not been updated to include <tt>cbegin</tt>, 22958<tt>cend</tt>, <tt>crbegin</tt> and <tt>crend</tt>. 22959</p> 22960 22961<p><i>[ 229622009-10-28 Howard: 22963]</i></p> 22964 22965 22966<blockquote> 22967Moved to Tentatively NAD after 5 positive votes on c++std-lib. Added 22968rationale. 22969</blockquote> 22970 22971<p><i>[ 229722009-10-28 Alisdair disagrees: 22973]</i></p> 22974 22975 22976<blockquote> 22977<p> 22978I'm going to have to speak up as the dissenting voice. 22979</p> 22980 22981<p> 22982I agree the issue could be handled editorially, and that would be my 22983preference if Pete feels this is appropriate. Failing that, I really 22984think this issue should be accepted and moved to ready. The other 22985begin/end functions all have a semantic definition for this template, 22986and it is confusing if a small few are missing. 22987</p> 22988 22989<p> 22990I agree that an alternative would be to strike <em>all</em> the definitions for 22991<tt>begin/end/rbegin/rend</tt> and defer completely to the requirements tables in 22992clause 23. I think that might be confusing without a forward reference 22993though, as those tables are defined in a *later* clause than the 22994basic_string template itself. If someone wants to pursue this I would 22995support it, but recommend it as a separate issue. 22996</p> 22997 22998<p> 22999So my preference is strongly to move Ready over NAD, and a stronger 23000preference for NAD Editorial if Pete is happy to make these changes. 23001</p> 23002 23003</blockquote> 23004 23005<p><i>[ 230062009-10-29 Howard: 23007]</i></p> 23008 23009 23010<blockquote> 23011Moved to Tentatively Ready after 5 positive votes on c++std-lib. Removed 23012rationale to mark it NAD. :-) 23013</blockquote> 23014 23015 23016 23017<p><b>Proposed resolution:</b></p> 23018<p> 23019Add to 21.4.3 [string.iterators] 23020</p> 23021 23022<blockquote><pre>iterator begin(); 23023const_iterator begin() const; 23024<ins>const_iterator cbegin() const;</ins> 23025</pre> 23026 23027<p>...</p> 23028 23029<pre>iterator end(); 23030const_iterator end() const; 23031<ins>const_iterator cend() const;</ins> 23032</pre> 23033 23034<p>...</p> 23035 23036<pre>reverse_iterator rbegin(); 23037const_reverse_iterator rbegin() const; 23038<ins>const_reverse_iterator crbegin() const;</ins> 23039</pre> 23040 23041<p>...</p> 23042 23043<pre>reverse_iterator rend(); 23044const_reverse_iterator rend() const; 23045<ins>const_reverse_iterator crend() const;</ins> 23046</pre> 23047 23048</blockquote> 23049 23050 23051 23052 23053 23054<hr> 23055<h3><a name="1193"></a>1193. <tt>default_delete</tt> cannot be instantiated with incomplete types</h3> 23056<p><b>Section:</b> 20.8.14.1 [unique.ptr.dltr] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 23057 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2009-08-18 <b>Last modified:</b> 2009-08-22</p> 23058<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 23059<p><b>Discussion:</b></p> 23060<p> 23061According to the general rules of 17.6.3.8 [res.on.functions]/2 b 5 the effects 23062are undefined, if an incomplete type is used to instantiate a library template. But neither in 2306320.8.14.1 [unique.ptr.dltr] nor 23064in any other place of the standard such explicit allowance is given. 23065Since this template is intended to be instantiated with incomplete 23066types, this must 23067be fixed. 23068</p> 23069 23070 23071<p><b>Proposed resolution:</b></p> 23072<p> 23073Add two new paragraphs directly to 20.8.14.1 [unique.ptr.dltr] (before 2307420.8.14.1.1 [unique.ptr.dltr.dflt]) with the following 23075content: 23076</p> 23077 23078<blockquote> 23079<p><ins> 23080The class template <tt>default_delete</tt> serves as the default deleter (destruction policy) for 23081the class template <tt>unique_ptr</tt>. 23082</ins></p> 23083 23084<p><ins> 23085The template parameter <tt>T</tt> of <tt>default_delete</tt> may be an incomplete type. 23086</ins></p> 23087</blockquote> 23088 23089 23090 23091 23092 23093<hr> 23094<h3><a name="1194"></a>1194. Unintended <tt>queue</tt> constructor</h3> 23095<p><b>Section:</b> 23.3.5 [container.adaptors] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 23096 <b>Submitter:</b> Howard Hinnant <b>Opened:</b> 2009-08-20 <b>Last modified:</b> 2009-10-20</p> 23097<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#container.adaptors">active issues</a> in [container.adaptors].</p> 23098<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#container.adaptors">issues</a> in [container.adaptors].</p> 23099<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 23100<p><b>Discussion:</b></p> 23101<p> 2310223.3.5.1.1 [queue.defn] has the following <tt>queue</tt> constructor: 23103</p> 23104 23105<blockquote><pre>template <class Alloc> explicit queue(const Alloc&); 23106</pre></blockquote> 23107 23108<p> 23109This will be implemented like so: 23110</p> 23111 23112<blockquote><pre>template <class Alloc> explicit queue(const Alloc& a) : c(a) {} 23113</pre></blockquote> 23114 23115<p> 23116The issue is that <tt>Alloc</tt> can be anything that a container will construct 23117from, for example an <tt>int</tt>. Is this intended to compile? 23118</p> 23119 23120<blockquote><pre>queue<int> q(5); 23121</pre></blockquote> 23122 23123<p> 23124Before the addition of this constructor, <tt>queue<int>(5)</tt> would not compile. 23125I ask, not because this crashes, but because it is new and appears to be 23126unintended. We do not want to be in a position of accidently introducing this 23127"feature" in C++0X and later attempting to remove it. 23128</p> 23129 23130<p> 23131I've picked on <tt>queue</tt>. <tt>priority_queue</tt> and <tt>stack</tt> have 23132the same issue. Is it useful to create a <tt>priority_queue</tt> of 5 23133identical elements? 23134</p> 23135 23136<p><i>[ 23137Daniel, Howard and Pablo collaborated on the proposed wording. 23138]</i></p> 23139 23140 23141<p><i>[ 231422009-10 Santa Cruz: 23143]</i></p> 23144 23145 23146<blockquote> 23147Move to Ready. 23148</blockquote> 23149 23150 23151 23152<p><b>Proposed resolution:</b></p> 23153 23154<p><i>[ 23155This resolution includes a semi-editorial clean up, giving definitions to members 23156which in some cases weren't defined since C++98. 23157This resolution also offers editorially different wording for <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#976">976</a>, 23158and it also provides wording for <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1196">1196</a>. 23159]</i></p> 23160 23161 23162<p> 23163Change container.adaptors, p1: 23164</p> 23165 23166<blockquote> 23167The container adaptors each take a <tt>Container</tt> template parameter, and 23168each constructor takes a <tt>Container</tt> reference argument. This container is 23169copied into the <tt>Container</tt> member of each adaptor. If the container takes 23170an allocator, then a compatible allocator may be passed in to the 23171adaptor's constructor. Otherwise, normal copy or move construction is 23172used for the container argument. <del>[<i>Note:</i> it is not necessary for an 23173implementation to distinguish between the one-argument constructor that 23174takes a <tt>Container</tt> and the one- argument constructor that takes an 23175allocator_type. Both forms use their argument to construct an instance 23176of the container. — <i>end note</i>]</del> 23177</blockquote> 23178 23179<p> 23180Change queue.defn, p1: 23181</p> 23182 23183<blockquote><pre>template <class T, class Container = deque<T> > 23184class queue { 23185public: 23186 typedef typename Container::value_type value_type; 23187 typedef typename Container::reference reference; 23188 typedef typename Container::const_reference const_reference; 23189 typedef typename Container::size_type size_type; 23190 typedef Container container_type; 23191protected: 23192 Container c; 23193 23194public: 23195 explicit queue(const Container&); 23196 explicit queue(Container&& = Container()); 23197 queue(queue&& q)<ins>;</ins><del> : c(std::move(q.c)) {}</del> 23198 template <class Alloc> explicit queue(const Alloc&); 23199 template <class Alloc> queue(const Container&, const Alloc&); 23200 template <class Alloc> queue(Container&&, const Alloc&); 23201 template <class Alloc> queue(queue&&, const Alloc&); 23202 queue& operator=(queue&& q)<ins>;</ins><del> { c = std::move(q.c); return *this; }</del> 23203 23204 bool empty() const { return c.empty(); } 23205 ... 23206}; 23207</pre></blockquote> 23208 23209<p> 23210Add a new section after 23.3.5.1.1 [queue.defn], [queue.cons]: 23211</p> 23212 23213<blockquote> 23214<p><b><tt>queue</tt> constructors [queue.cons]</b></p> 23215 23216<pre>explicit queue(const Container& cont); 23217</pre> 23218 23219<blockquote> 23220 23221<p> 23222<i>Effects:</i> Initializes <tt>c</tt> with <tt>cont</tt>. 23223</p> 23224 23225</blockquote> 23226 23227<pre>explicit queue(Container&& cont = Container()); 23228</pre> 23229 23230<blockquote> 23231 23232<p> 23233<i>Effects:</i> Initializes <tt>c</tt> with <tt>std::move(cont)</tt>. 23234</p> 23235 23236</blockquote> 23237 23238<pre>queue(queue&& q) 23239</pre> 23240 23241<blockquote> 23242 23243<p> 23244<i>Effects:</i> Initializes <tt>c</tt> with <tt>std::move(q.c)</tt>. 23245</p> 23246 23247</blockquote> 23248 23249<p> 23250For each of the following constructors, 23251if <tt>uses_allocator<container_type, Alloc>::value</tt> is <tt>false</tt>, 23252then the constructor shall not participate in overload resolution. 23253</p> 23254 23255<pre>template <class Alloc> 23256 explicit queue(const Alloc& a); 23257</pre> 23258 23259<blockquote> 23260 23261<p> 23262<i>Effects:</i> Initializes <tt>c</tt> with <tt>a</tt>. 23263</p> 23264 23265</blockquote> 23266 23267<pre>template <class Alloc> 23268 queue(const container_type& cont, const Alloc& a); 23269</pre> 23270 23271<blockquote> 23272 23273<p> 23274<i>Effects:</i> Initializes <tt>c</tt> with <tt>cont</tt> as the first 23275argument and <tt>a</tt> as the second argument. 23276</p> 23277 23278</blockquote> 23279 23280<pre>template <class Alloc> 23281 queue(container_type&& cont, const Alloc& a); 23282</pre> 23283 23284<blockquote> 23285 23286<p> 23287<i>Effects:</i> Initializes <tt>c</tt> with <tt>std::move(cont)</tt> as the 23288first argument and <tt>a</tt> as the second argument. 23289</p> 23290 23291</blockquote> 23292 23293<pre>template <class Alloc> 23294 queue(queue&& q, const Alloc& a); 23295</pre> 23296 23297<blockquote> 23298 23299<p> 23300<i>Effects:</i> Initializes <tt>c</tt> with <tt>std::move(q.c)</tt> as the 23301first argument and <tt>a</tt> as the second argument. 23302</p> 23303 23304</blockquote> 23305 23306<pre>queue& operator=(queue&& q); 23307</pre> 23308 23309<blockquote> 23310 23311<p> 23312<i>Effects:</i> Assigns <tt>c</tt> with <tt>std::move(q.c)</tt>. 23313</p> 23314 23315<p> 23316<i>Returns:</i> <tt>*this</tt>. 23317</p> 23318 23319</blockquote> 23320 23321 23322 23323</blockquote> 23324 23325<p> 23326Add to 23.3.5.2.1 [priqueue.cons]: 23327</p> 23328 23329<blockquote> 23330 23331<pre>priority_queue(priority_queue&& q); 23332</pre> 23333 23334<blockquote> 23335 23336<p> 23337<i>Effects:</i> Initializes <tt>c</tt> with <tt>std::move(q.c)</tt> and 23338initializes <tt>comp</tt> with <tt>std::move(q.comp)</tt>. 23339</p> 23340 23341</blockquote> 23342 23343<p> 23344For each of the following constructors, 23345if <tt>uses_allocator<container_type, Alloc>::value</tt> is <tt>false</tt>, 23346then the constructor shall not participate in overload resolution. 23347</p> 23348 23349<pre>template <class Alloc> 23350 explicit priority_queue(const Alloc& a); 23351</pre> 23352 23353<blockquote> 23354 23355<p> 23356<i>Effects:</i> Initializes <tt>c</tt> with <tt>a</tt> and value-initializes <tt>comp</tt>. 23357</p> 23358 23359</blockquote> 23360 23361<pre>template <class Alloc> 23362 priority_queue(const Compare& compare, const Alloc& a); 23363</pre> 23364 23365<blockquote> 23366 23367<p> 23368<i>Effects:</i> Initializes <tt>c</tt> with <tt>a</tt> and initializes <tt>comp</tt> 23369with <tt>compare</tt>. 23370</p> 23371 23372</blockquote> 23373 23374<pre>template <class Alloc> 23375 priority_queue(const Compare& compare, const Container& cont, const Alloc& a); 23376</pre> 23377 23378<blockquote> 23379 23380<p> 23381<i>Effects:</i> Initializes <tt>c</tt> with <tt>cont</tt> as the first argument 23382and <tt>a</tt> as the second argument, 23383and initializes <tt>comp</tt> with <tt>compare</tt>. 23384</p> 23385 23386</blockquote> 23387 23388<pre>template <class Alloc> 23389 priority_queue(const Compare& compare, Container&& cont, const Alloc& a); 23390</pre> 23391 23392<blockquote> 23393 23394<p> 23395<i>Effects:</i> Initializes <tt>c</tt> with <tt>std::move(cont)</tt> as 23396the first argument and <tt>a</tt> as the second argument, 23397and initializes <tt>comp</tt> with <tt>compare</tt>. 23398</p> 23399 23400</blockquote> 23401 23402<pre>template <class Alloc> 23403 priority_queue(priority_queue&& q, const Alloc& a); 23404</pre> 23405 23406<blockquote> 23407 23408<p> 23409<i>Effects:</i> Initializes <tt>c</tt> with <tt>std::move(q.c)</tt> as the 23410first argument and <tt>a</tt> as the second argument, 23411and initializes <tt>comp</tt> with <tt>std::move(q.comp)</tt>. 23412</p> 23413 23414</blockquote> 23415 23416<pre>priority_queue& operator=(priority_queue&& q); 23417</pre> 23418 23419<blockquote> 23420 23421<p> 23422<i>Effects:</i> Assigns <tt>c</tt> with <tt>std::move(q.c)</tt> and 23423assigns <tt>comp</tt> with <tt>std::move(q.comp)</tt>. 23424</p> 23425 23426<p> 23427<i>Returns:</i> <tt>*this</tt>. 23428</p> 23429 23430</blockquote> 23431 23432</blockquote> 23433 23434 23435 23436 23437<p> 23438Change 23.3.5.3.1 [stack.defn]: 23439</p> 23440 23441<blockquote><pre>template <class T, class Container = deque<T> > 23442class stack { 23443public: 23444 typedef typename Container::value_type value_type; 23445 typedef typename Container::reference reference; 23446 typedef typename Container::const_reference const_reference; 23447 typedef typename Container::size_type size_type; 23448 typedef Container container_type; 23449protected: 23450 Container c; 23451 23452public: 23453 explicit stack(const Container&); 23454 explicit stack(Container&& = Container()); 23455 <ins>stack(stack&& s);</ins> 23456 template <class Alloc> explicit stack(const Alloc&); 23457 template <class Alloc> stack(const Container&, const Alloc&); 23458 template <class Alloc> stack(Container&&, const Alloc&); 23459 template <class Alloc> stack(stack&&, const Alloc&); 23460 <ins>stack& operator=(stack&& s);</ins> 23461 23462 bool empty() const { return c.empty(); } 23463 ... 23464}; 23465</pre></blockquote> 23466 23467<p> 23468Add a new section after 23.3.5.3.1 [stack.defn], [stack.cons]: 23469</p> 23470 23471<blockquote> 23472<p><b><tt>stack</tt> constructors [stack.cons]</b></p> 23473 23474<pre>stack(stack&& s); 23475</pre> 23476 23477<blockquote> 23478 23479<p> 23480<i>Effects:</i> Initializes <tt>c</tt> with <tt>std::move(s.c)</tt>. 23481</p> 23482 23483</blockquote> 23484 23485<p> 23486For each of the following constructors, 23487if <tt>uses_allocator<container_type, Alloc>::value</tt> is <tt>false</tt>, 23488then the constructor shall not participate in overload resolution. 23489</p> 23490 23491<pre>template <class Alloc> 23492 explicit stack(const Alloc& a); 23493</pre> 23494 23495<blockquote> 23496 23497<p> 23498<i>Effects:</i> Initializes <tt>c</tt> with <tt>a</tt>. 23499</p> 23500 23501</blockquote> 23502 23503<pre>template <class Alloc> 23504 stack(const container_type& cont, const Alloc& a); 23505</pre> 23506 23507<blockquote> 23508 23509<p> 23510<i>Effects:</i> Initializes <tt>c</tt> with <tt>cont</tt> as the 23511first argument and <tt>a</tt> as the second argument. 23512</p> 23513 23514</blockquote> 23515 23516<pre>template <class Alloc> 23517 stack(container_type&& cont, const Alloc& a); 23518</pre> 23519 23520<blockquote> 23521 23522<p> 23523<i>Effects:</i> Initializes <tt>c</tt> with <tt>std::move(cont)</tt> as the 23524first argument and <tt>a</tt> as the second argument. 23525</p> 23526 23527</blockquote> 23528 23529<pre>template <class Alloc> 23530 stack(stack&& s, const Alloc& a); 23531</pre> 23532 23533<blockquote> 23534 23535<p> 23536<i>Effects:</i> Initializes <tt>c</tt> with <tt>std::move(s.c)</tt> as the 23537first argument and <tt>a</tt> as the second argument. 23538</p> 23539 23540</blockquote> 23541 23542<pre>stack& operator=(stack&& s); 23543</pre> 23544 23545<blockquote> 23546 23547<p> 23548<i>Effects:</i> Assigns <tt>c</tt> with <tt>std::move(s.c)</tt>. 23549</p> 23550 23551<p> 23552<i>Returns:</i> <tt>*this</tt>. 23553</p> 23554 23555</blockquote> 23556 23557</blockquote> 23558 23559 23560 23561 23562 23563 23564<hr> 23565<h3><a name="1197"></a>1197. Can unordered containers have <tt>bucket_count() == 0</tt>?</h3> 23566<p><b>Section:</b> 23.2.5 [unord.req] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 23567 <b>Submitter:</b> Howard Hinnant <b>Opened:</b> 2009-08-24 <b>Last modified:</b> 2009-09-03</p> 23568<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#unord.req">active issues</a> in [unord.req].</p> 23569<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#unord.req">issues</a> in [unord.req].</p> 23570<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 23571<p><b>Discussion:</b></p> 23572<p> 23573Table 97 "Unordered associative container requirements" in 2357423.2.5 [unord.req] says: 23575</p> 23576 23577<blockquote> 23578<table border="1"> 23579<caption>Table 97 — Unordered associative container requirements 23580(in addition to container)</caption> 23581 23582<tbody><tr> 23583<th>Expression</th> 23584<th>Return type</th> 23585<th>Assertion/note pre-/post-condition</th> 23586<th>Complexity</th> 23587</tr> 23588 23589<tr> 23590<td><tt>b.bucket(k)</tt></td> 23591<td><tt>size_type</tt></td> 23592<td>Returns the index of the bucket in which elements with keys 23593equivalent to <tt>k</tt> would be found, 23594if any such element existed. 23595Post: the return value shall be 23596in the range <tt>[0, 23597b.bucket_count())</tt>.</td> 23598<td>Constant</td> 23599</tr> 23600 23601</tbody></table> 23602</blockquote> 23603 23604<p> 23605What should <tt>b.bucket(k)</tt> return if <tt>b.bucket_count() == 0</tt>? 23606</p> 23607 23608<p> 23609I believe allowing <tt>b.bucket_count() == 0</tt> is important. It is a 23610very reasonable post-condition of the default constructor, or of a moved-from 23611container. 23612</p> 23613 23614<p> 23615I can think of several reasonable results from <tt>b.bucket(k)</tt> when 23616<tt>b.bucket_count() == 0</tt>: 23617</p> 23618 23619<ol> 23620<li> 23621Return 0. 23622</li> 23623<li> 23624Return <tt>numeric_limits<size_type>::max()</tt>. 23625</li> 23626<li> 23627Throw a <tt>domain_error</tt>. 23628</li> 23629<li> 23630Precondition: <tt>b.bucket_count() != 0</tt>. 23631</li> 23632</ol> 23633 23634<p><i>[ 236352009-08-26 Daniel adds: 23636]</i></p> 23637 23638 23639<blockquote> 23640<p> 23641A forth choice would be to add the pre-condition "<tt>b.bucket_count() != 0</tt>" 23642and thus imply undefined behavior if this is violated. 23643</p> 23644 23645<p><i>[ 23646Howard: I like this option too, added to the list. 23647]</i></p> 23648 23649 23650<p> 23651Further on here my own favorite solution (rationale see below): 23652</p> 23653 23654<p><b>Suggested resolution:</b></p> 23655 23656<p> 23657[Rationale: I suggest to follow choice (1). The main reason is 23658that all associative container functions which take a key argument, 23659are basically free of pre-conditions and non-disrupting, therefore 23660excluding choices (3) and (4). Option (2) seems a bit unexpected 23661to me. It would be more natural, if several similar functions 23662would exist which would also justify the existence of a symbolic 23663constant like npos for this situation. The value 0 is both simple 23664and consistent, it has exactly the same role as a past-the-end 23665iterator value. A typical use-case is: 23666</p> 23667 23668<blockquote><pre>size_type pos = m.bucket(key); 23669if (pos != m.bucket_count()) { 23670 ... 23671} else { 23672 ... 23673} 23674</pre></blockquote> 23675 23676<p>— end Rationale]</p> 23677 23678<p> 23679- Change Table 97 in 23.2.5 [unord.req] as follows (Row b.bucket(k), Column "Assertion/..."): 23680</p> 23681 23682<blockquote> 23683<table border="1"> 23684<caption>Table 97 — Unordered associative container requirements 23685(in addition to container)</caption> 23686 23687<tbody><tr> 23688<th>Expression</th> 23689<th>Return type</th> 23690<th>Assertion/note pre-/post-condition</th> 23691<th>Complexity</th> 23692</tr> 23693 23694<tr> 23695<td><tt>b.bucket(k)</tt></td> 23696<td><tt>size_type</tt></td> 23697<td>Returns the index of the bucket in which elements with keys 23698equivalent to <tt>k</tt> would be found, 23699if any such element existed. 23700Post: <ins>if b.bucket_count() != 0, </ins>the return value shall be 23701in the range <tt>[0, 23702b.bucket_count())</tt><ins>, otherwise 0</ins>.</td> 23703<td>Constant</td> 23704</tr> 23705 23706</tbody></table> 23707</blockquote> 23708 23709</blockquote> 23710 23711 23712 23713<p><b>Proposed resolution:</b></p> 23714<p> 23715</p> 23716 23717 23718 23719 23720 23721<hr> 23722<h3><a name="1198"></a>1198. Container adaptor swap: member or non-member?</h3> 23723<p><b>Section:</b> 23.3.5 [container.adaptors] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 23724 <b>Submitter:</b> Pablo Halpern <b>Opened:</b> 2009-08-26 <b>Last modified:</b> 2009-09-30</p> 23725<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#container.adaptors">active issues</a> in [container.adaptors].</p> 23726<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#container.adaptors">issues</a> in [container.adaptors].</p> 23727<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 23728<p><b>Discussion:</b></p> 23729<p> 23730Under 23.3.5 [container.adaptors] of 23731<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2914.pdf">N2914</a> 23732the member function of <tt>swap</tt> of <tt>queue</tt> and <tt>stack</tt> call: 23733</p> 23734 23735<blockquote><pre>swap(c, q.c); 23736</pre></blockquote> 23737 23738<p> 23739But under 23.3.5 [container.adaptors] of 23740<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2723.pdf">N2723</a> 23741these members are specified to call: 23742</p> 23743 23744<blockquote><pre>c.swap(q.c); 23745</pre></blockquote> 23746 23747<p> 23748Neither draft specifies the semantics of member <tt>swap</tt> for 23749<tt>priority_queue</tt> though it is declared. 23750</p> 23751 23752<p> 23753Although the distinction between member <tt>swap</tt> and non-member 23754<tt>swap</tt> is not important when these adaptors are adapting standard 23755containers, it may be important for user-defined containers. 23756</p> 23757<p> 23758We (Pablo and Howard) feel that 23759it is more likely for a user-defined container to support a namespace scope 23760<tt>swap</tt> than a member <tt>swap</tt>, and therefore these adaptors 23761should use the container's namespace scope <tt>swap</tt>. 23762</p> 23763 23764<p><i>[ 237652009-09-30 Daniel adds: 23766]</i></p> 23767 23768 23769<blockquote> 23770The outcome of this issue should be considered with the outcome of <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#774">774</a> both in style and in content (e.g. <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#774">774</a> bullet 9 23771suggests to define the semantic of <tt>void 23772priority_queue::swap(priority_queue&)</tt> in terms of the member 23773<tt>swap</tt> of the container). 23774</blockquote> 23775 23776 23777 23778<p><b>Proposed resolution:</b></p> 23779<p><i>[ 23780Changes written with respect to 23781<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2723.pdf">N2723</a>. 23782]</i></p> 23783 23784 23785<p> 23786Change 23.3.5.1.1 [queue.defn]: 23787</p> 23788 23789<blockquote><pre>template <class T, class Container = deque<T> > 23790class queue { 23791 ... 23792 void swap(queue&<del>&</del> q) { <ins>using std::swap;</ins> 23793 <del>c.</del>swap(<ins>c, </ins>q.c); } 23794 ... 23795}; 23796</pre></blockquote> 23797 23798<p> 23799Change 23.3.5.2 [priority.queue]: 23800</p> 23801 23802<blockquote><pre>template <class T, class Container = vector<T>, 23803 class Compare = less<typename Container::value_type> > 23804class priority_queue { 23805 ... 23806 void swap(priority_queue&<del>&</del> <ins>q</ins>)<del>;</del> <ins>{ using std::swap;</ins> 23807 <ins>swap(c, q.c);</ins> 23808 <ins>swap(comp, q.comp); }</ins> 23809 ... 23810}; 23811</pre></blockquote> 23812 23813<p> 23814Change 23.3.5.3.1 [stack.defn]: 23815</p> 23816 23817<blockquote><pre>template <class T, class Container = deque<T> > 23818class stack { 23819 ... 23820 void swap(stack&<del>&</del> s) { <ins>using std::swap;</ins> 23821 <del>c.</del>swap(<ins>c, </ins>s.c); } 23822 ... 23823}; 23824</pre></blockquote> 23825 23826 23827 23828 23829 23830 23831<hr> 23832<h3><a name="1199"></a>1199. Missing extended copy constructor in container adaptors</h3> 23833<p><b>Section:</b> 23.3.5 [container.adaptors] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 23834 <b>Submitter:</b> Pablo Halpern <b>Opened:</b> 2009-08-26 <b>Last modified:</b> 2009-08-31</p> 23835<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#container.adaptors">active issues</a> in [container.adaptors].</p> 23836<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#container.adaptors">issues</a> in [container.adaptors].</p> 23837<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 23838<p><b>Discussion:</b></p> 23839<p> 23840<tt>queue</tt> has a constructor: 23841</p> 23842 23843<blockquote><pre>template <class Alloc> 23844 queue(queue&&, const Alloc&); 23845</pre></blockquote> 23846 23847<p> 23848but it is missing a corresponding constructor: 23849</p> 23850 23851<blockquote><pre>template <class Alloc> 23852 queue(const queue&, const Alloc&); 23853</pre></blockquote> 23854 23855<p> 23856The same is true of <tt>priority_queue</tt>, and <tt>stack</tt>. This 23857"extended copy constructor" is needed for consistency and to ensure that the 23858user of a container adaptor can always specify the allocator for his adaptor. 23859</p> 23860 23861 23862 23863<p><b>Proposed resolution:</b></p> 23864<p><i>[ 23865This resolution has been harmonized with the proposed resolution to issue 23866<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1194">1194</a> 23867]</i></p> 23868 23869 23870<p>Change 23.3.5.1.1 [queue.defn], p1:</p> 23871 23872<blockquote><pre>template <class T, class Container = deque<T> > 23873class queue { 23874public: 23875 typedef typename Container::value_type value_type; 23876 typedef typename Container::reference reference; 23877 typedef typename Container::const_reference const_reference; 23878 typedef typename Container::size_type size_type; 23879 typedef Container container_type; 23880protected: 23881 Container c; 23882 23883public: 23884 explicit queue(const Container&); 23885 explicit queue(Container&& = Container()); 23886 queue(queue&& q); 23887 23888 template <class Alloc> explicit queue(const Alloc&); 23889 template <class Alloc> queue(const Container&, const Alloc&); 23890 template <class Alloc> queue(Container&&, const Alloc&); 23891 <ins>template <class Alloc> queue(const queue&, const Alloc&);</ins> 23892 template <class Alloc> queue(queue&&, const Alloc&); 23893 queue& operator=(queue&& q); 23894 23895 bool empty() const { return c.empty(); } 23896 ... 23897}; 23898</pre></blockquote> 23899 23900<p> 23901To the new section [queue.cons], introduced 23902in <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1194">1194</a>, add: 23903</p> 23904 23905<blockquote> 23906 23907<pre>template <class Alloc> 23908 queue(const queue& q, const Alloc& a); 23909</pre> 23910 23911<blockquote><p> 23912<i>Effects:</i> Initializes <tt>c</tt> with <tt>q.c</tt> as the 23913first argument and <tt>a</tt> as the second argument. 23914</p></blockquote> 23915 23916</blockquote> 23917 23918<p>Change 23.3.5.2 [priority.queue] as follows (I've an included an editorial change to 23919 move the poorly-placed move-assignment operator):</p> 23920 23921<blockquote><pre>template <class T, class Container = vector<T>, 23922 class Compare = less<typename Container::value_type> > 23923class priority_queue { 23924public: 23925 typedef typename Container::value_type value_type; 23926 typedef typename Container::reference reference; 23927 typedef typename Container::const_reference const_reference; 23928 typedef typename Container::size_type size_type; 23929 typedef Container container_type; 23930protected: 23931 Container c; 23932 Compare comp; 23933 23934public: 23935 priority_queue(const Compare& x, const Container&); 23936 explicit priority_queue(const Compare& x = Compare(), Container&& = Container()); 23937 template <class InputIterator> 23938 priority_queue(InputIterator first, InputIterator last, 23939 const Compare& x, const Container&); 23940 template <class InputIterator> 23941 priority_queue(InputIterator first, InputIterator last, 23942 const Compare& x = Compare(), Container&& = Container()); 23943 priority_queue(priority_queue&&); 23944 <del>priority_queue& operator=(priority_queue&&);</del> 23945 template <class Alloc> explicit priority_queue(const Alloc&); 23946 template <class Alloc> priority_queue(const Compare&, const Alloc&); 23947 template <class Alloc> priority_queue(const Compare&, 23948 const Container&, const Alloc&); 23949 template <class Alloc> priority_queue(const Compare&, 23950 Container&&, const Alloc&); 23951 <ins>template <class Alloc> priority_queue(const priority_queue&, const Alloc&);</ins> 23952 template <class Alloc> priority_queue(priority_queue&&, const Alloc&); 23953 23954 <ins>priority_queue& operator=(priority_queue&&);</ins> 23955 ... 23956}; 23957</pre></blockquote> 23958 23959<p> 23960Add to 23.3.5.2.1 [priqueue.cons]: 23961</p> 23962 23963<blockquote> 23964 23965<pre>template <class Alloc> 23966 explicit priority_queue(const priority_queue& q, const Alloc& a); 23967</pre> 23968 23969<blockquote><p> 23970<i>Effects:</i> Initializes <tt>c</tt> with <tt>q.c</tt> as the 23971first argument and <tt>a</tt> as the second argument, 23972and initializes <tt>comp</tt> with <tt>q.comp</tt>. 23973</p></blockquote> 23974 23975</blockquote> 23976 23977<p> 23978Change 23.3.5.3.1 [stack.defn]: 23979</p> 23980 23981<blockquote><pre>template <class T, class Container = deque<T> > 23982class stack { 23983public: 23984 typedef typename Container::value_type value_type; 23985 typedef typename Container::reference reference; 23986 typedef typename Container::const_reference const_reference; 23987 typedef typename Container::size_type size_type; 23988 typedef Container container_type; 23989protected: 23990 Container c; 23991 23992public: 23993 explicit stack(const Container&); 23994 explicit stack(Container&& = Container()); 23995 stack(stack&& s); 23996 23997 template <class Alloc> explicit stack(const Alloc&); 23998 template <class Alloc> stack(const Container&, const Alloc&); 23999 template <class Alloc> stack(Container&&, const Alloc&); 24000 <ins>template <class Alloc> stack(const stack&, const Alloc&);</ins> 24001 template <class Alloc> stack(stack&&, const Alloc&); 24002 stack& operator=(stack&& s); 24003 24004 bool empty() const { return c.empty(); } 24005 ... 24006}; 24007</pre></blockquote> 24008 24009<p> 24010To the new section [stack.cons], introduced 24011in <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1194">1194</a>, add: 24012</p> 24013 24014<blockquote> 24015 24016<pre>template <class Alloc> 24017 stack(const stack& s, const Alloc& a); 24018</pre> 24019 24020<blockquote><p> 24021<i>Effects:</i> Initializes <tt>c</tt> with <tt>s.c</tt> as the 24022first argument and <tt>a</tt> as the second argument. 24023</p></blockquote> 24024</blockquote> 24025 24026 24027 24028 24029 24030 24031<hr> 24032<h3><a name="1200"></a>1200. "surprising" <tt>char_traits<T>::int_type</tt> requirements</h3> 24033<p><b>Section:</b> 21.2.2 [char.traits.typedefs] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 24034 <b>Submitter:</b> Sean Hunt <b>Opened:</b> 2009-09-03 <b>Last modified:</b> 2009-10-28</p> 24035<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#char.traits.typedefs">issues</a> in [char.traits.typedefs].</p> 24036<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 24037<p><b>Discussion:</b></p> 24038<p> 24039The footnote for <tt>int_type</tt> in 21.2.2 [char.traits.typedefs] says that 24040</p> 24041 24042<blockquote> 24043If <tt>eof()</tt> 24044can be held in <tt>char_type</tt> then some iostreams implementations may give 24045surprising results. 24046</blockquote> 24047 24048<p> 24049This implies that <tt>int_type</tt> should be a superset of 24050<tt>char_type</tt>. However, the requirements for <tt>char16_t</tt> and <tt>char32_t</tt> define 24051<tt>int_type</tt> to be equal to <tt>int_least16_t</tt> and <tt>int_least32_t</tt> respectively. 24052<tt>int_least16_t</tt> is likely to be the same size as <tt>char_16_t</tt>, which may lead 24053to surprising behavior, even if <tt>eof()</tt> is not a valid UTF-16 code unit. 24054The standard should not prescribe surprising behavior, especially 24055without saying what it is (it's apparently not undefined, just 24056surprising). The same applies for 32-bit types. 24057</p> 24058 24059<p> 24060I personally recommend that behavior be undefined if <tt>eof()</tt> is a member 24061of <tt>char_type</tt>, and another type be chosen for <tt>int_type</tt> (my personal 24062favorite has always been a <tt>struct {bool eof; char_type c;}</tt>). 24063Alternatively, the exact results of such a situation should be defined, 24064at least so far that I/O could be conducted on these types as long as 24065the code units remain valid. Note that the argument that no one streams 24066<tt>char16_t</tt> or <tt>char32_t</tt> is not really valid as it would be perfectly 24067reasonable to use a <tt>basic_stringstream</tt> in conjunction with UTF character 24068types. 24069</p> 24070 24071<p><i>[ 240722009-10-28 Ganesh provides two possible resolutions and expresses a preference 24073for the second: 24074]</i></p> 24075 24076 24077<blockquote> 24078<ol> 24079<li> 24080<p> 24081Replace 21.2.3.2 [char.traits.specializations.char16_t] para 3 with: 24082</p> 24083 24084<blockquote> 24085The member <tt>eof()</tt> shall return <del>an implementation-defined 24086constant that cannot appear as a valid UTF-16 code unit</del> 24087<ins><tt>UINT_LEAST16_MAX</tt> [<i>Note:</i> this value is guaranteed to 24088be a permanently reserved UCS-2 code position if <tt>UINT_LEAST16_MAX == 240890xFFFF</tt> and it's not a UCS-2 code position otherwise — <i>end 24090note</i>]</ins>. 24091</blockquote> 24092 24093<p> 24094Replace 21.2.3.3 [char.traits.specializations.char32_t] para 3 with: 24095</p> 24096 24097<blockquote> 24098The member <tt>eof()</tt> shall return <del>an implementation-defined constant that 24099cannot appear as a Unicode code point</del> 24100<ins> 24101<tt>UINT_LEAST32_MAX</tt> [<i>Note:</i> this value is guaranteed to be a 24102permanently reserved UCS-4 code position if <tt>UINT_LEAST32_MAX == 241030xFFFFFFFF</tt> and it's not a UCS-4 code position otherwise — <i>end 24104note</i>]</ins>. 24105</blockquote> 24106</li> 24107<li> 24108<p> 24109In 21.2.3.2 [char.traits.specializations.char16_t], in the 24110definition of <tt>char_traits<char16_t></tt> replace the definition of nested 24111typedef <tt>int_type</tt> with: 24112</p> 24113 24114<blockquote><pre>namespace std { 24115 template<> struct char_traits<char16_t> { 24116 typedef char16_t char_type; 24117 typedef <del>uint_least16_t</del> <ins>uint_fast16_t</ins> int_type; 24118 ... 24119</pre></blockquote> 24120 24121<p> 24122Replace 21.2.3.2 [char.traits.specializations.char16_t] para 3 with: 24123</p> 24124 24125<blockquote> 24126The member <tt>eof()</tt> shall return <del>an implementation-defined 24127constant that cannot appear as a valid UTF-16 code unit</del> 24128<ins><tt>UINT_FAST16_MAX</tt> [<i>Note:</i> this value is guaranteed to 24129be a permanently reserved UCS-2 code position if <tt>UINT_FAST16_MAX == 241300xFFFF</tt> and it's not a UCS-2 code position otherwise — <i>end 24131note</i>]</ins>. 24132</blockquote> 24133 24134<p> 24135In 21.2.3.3 [char.traits.specializations.char32_t], in the 24136definition of <tt>char_traits<char32_t></tt> replace the definition of nested 24137typedef <tt>int_type</tt> with: 24138</p> 24139 24140<blockquote><pre>namespace std { 24141 template<> struct char_traits<char32_t> { 24142 typedef char32_t char_type; 24143 typedef <del>uint_least32_t</del> <ins>uint_fast32_t</ins> int_type; 24144 ... 24145</pre></blockquote> 24146 24147<p> 24148Replace 21.2.3.3 [char.traits.specializations.char32_t] para 3 with: 24149</p> 24150 24151<blockquote> 24152The member <tt>eof()</tt> shall return <del>an implementation-defined constant that 24153cannot appear as a Unicode code point</del> 24154<ins> 24155<tt>UINT_FAST32_MAX</tt> [<i>Note:</i> this value is guaranteed to be a 24156permanently reserved UCS-4 code position if <tt>UINT_FAST32_MAX == 241570xFFFFFFFF</tt> and it's not a UCS-4 code position otherwise — <i>end 24158note</i>]</ins>. 24159</blockquote> 24160</li> 24161</ol> 24162</blockquote> 24163 24164 24165 24166<p><b>Proposed resolution:</b></p> 24167<p> 24168</p> 24169 24170 24171 24172 24173 24174<hr> 24175<h3><a name="1201"></a>1201. Do we always want to unwrap <tt>ref</tt>-wrappers in <tt>make_tuple</tt></h3> 24176<p><b>Section:</b> 20.5.2.4 [tuple.creation], 20.3.4 [pairs] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Future">Tentatively NAD Future</a> 24177 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-09-05 <b>Last modified:</b> 2009-10-26</p> 24178<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20NAD%20Future">Tentatively NAD Future</a> status.</p> 24179<p><b>Discussion:</b></p> 24180<p> 24181Spotting a recent thread on the boost lists regarding collapsing 24182optional representations in <tt>optional<optional<T>></tt> instances, I wonder if 24183we have some of the same issues with <tt>make_tuple</tt>, and now <tt>make_pair</tt>? 24184</p> 24185 24186<p> 24187Essentially, if my generic code in my own library is handed a 24188<tt>reference_wrapper</tt> by a user, and my library in turn delegates some logic 24189to <tt>make_pair</tt> or <tt>make_tuple</tt>, then I am going to end up with a <tt>pair</tt>/<tt>tuple</tt> 24190holding a real reference rather than the intended reference wrapper. 24191</p> 24192 24193<p> 24194There are two things as a library author I can do at this point: 24195</p> 24196 24197<ol type="i"> 24198<li> 24199document my library also has the same reference-wrapper behaviour as 24200<tt>std::make_tuple</tt> 24201</li> 24202<li> 24203roll my own <tt>make_tuple</tt> that does not unwrap rereferences, a lost 24204opportunity to re-use the standard library. 24205</li> 24206</ol> 24207 24208<p> 24209(There may be some metaprogramming approaches my library can use to wrap 24210the <tt>make_tuple</tt> call, but all will be significantly more complex than 24211simply implementing a simplified <tt>make_tuple</tt>.) 24212</p> 24213 24214<p> 24215Now I don't propose we lose this library facility, I think unwrapping 24216references will be the common behaviour. However, we might want to 24217consider adding another overload that does nothing special with 24218<tt>ref</tt>-wrappers. Note that we already have a second overload of <tt>make_tuple</tt> 24219in the library, called <tt>tie</tt>. 24220</p> 24221 24222<p><i>[ 242232009-09-30 Daniel adds: 24224]</i></p> 24225 24226 24227<blockquote> 24228<p> 24229I suggest to change the currently proposed paragraph for 24230<tt>make_simple_pair</tt> 24231</p> 24232 24233<blockquote><pre>template<typename... Types> 24234 pair<typename decay<Types>::type...> make_simple_pair(Types&&... t); 24235</pre> 24236<blockquote> 24237<p> 24238<del><i>Type requirements:</i> <tt>sizeof...(Types) == 2</tt>.</del> 24239<ins><i>Remarks:</i> The program shall be ill-formed, if 24240<tt>sizeof...(Types) != 2</tt>.</ins> 24241</p> 24242<p> 24243... 24244</p> 24245</blockquote> 24246</blockquote> 24247 24248<p> 24249or alternatively (but with a slightly different semantic): 24250</p> 24251 24252<blockquote> 24253<blockquote> 24254<i>Remarks:</i> If <tt>sizeof...(Types) != 2</tt>, this function shall not 24255participate in overload resolution. 24256</blockquote> 24257</blockquote> 24258 24259<p> 24260to follow a currently introduced style and because the library does 24261not have yet a specific "<i>Type requirements</i>" element. If such thing 24262would be considered as useful this should be done as a separate 24263issue. Given the increasing complexity of either of these wordings 24264it might be preferable to use the normal two-argument-declaration 24265style again in either of the following ways: 24266</p> 24267 24268<ol type="A"> 24269<li> 24270<pre>template<class T1, class T2> 24271pair<typename decay<T1>::type, typename decay<T2>::type> 24272make_simple_pair(T1&& t1, T2&& t2); 24273</pre> 24274</li> 24275<li> 24276<pre>template<class T1, class T2> 24277pair<V1, V2> make_simple_pair(T1&& t1, T2&& t2); 24278</pre> 24279<blockquote> 24280Let <tt>V1</tt> be <tt>typename decay<T1>::type</tt> and <tt>V2</tt> be 24281<tt>typename decay<T2>::type</tt>. 24282</blockquote> 24283</li> 24284</ol> 24285 24286</blockquote> 24287 24288<p><i>[ 242892009-10 post-Santa Cruz: 24290]</i></p> 24291 24292 24293<blockquote> 24294Mark as Tentatively NAD Future. 24295</blockquote> 24296 24297 24298 24299<p><b>Proposed resolution:</b></p> 24300<p> 24301Add the following function to 20.3.4 [pairs] and signature in 24302appropriate synopses: 24303</p> 24304 24305<blockquote><pre>template<typename... Types> 24306 pair<typename decay<Types>::type...> make_simple_pair(Types&&... t); 24307</pre> 24308<blockquote> 24309<p> 24310<i>Type requirements:</i> <tt>sizeof...(Types) == 2</tt>. 24311</p> 24312<p> 24313<i>Returns:</i> <tt>pair<typename decay<Types>::type...>(std::forward<Types>(t)...)</tt>. 24314</p> 24315</blockquote> 24316</blockquote> 24317 24318<p><i>[ 24319Draughting note: I chose a variadic representation similar to <tt>make_tuple</tt> 24320rather than naming both types as it is easier to read through the 24321clutter of metaprogramming this way. Given there are exactly two 24322elements, the committee may prefer to draught with two explicit template 24323type parameters instead 24324]</i></p> 24325 24326 24327<p> 24328Add the following function to 20.5.2.4 [tuple.creation] and 24329signature in appropriate synopses: 24330</p> 24331 24332<blockquote><pre>template<typename... Types> 24333 tuple<typename decay<Types>::type...> make_simple_tuple(Types&&... t); 24334</pre> 24335<blockquote> 24336<p> 24337<i>Returns:</i> <tt>tuple<typename decay<Types>::type...>(std::forward<Types>(t)...)</tt>. 24338</p> 24339</blockquote> 24340</blockquote> 24341 24342 24343 24344 24345 24346<hr> 24347<h3><a name="1202"></a>1202. <tt>integral_constant</tt> needs a spring clean</h3> 24348<p><b>Section:</b> 20.6.3 [meta.help] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 24349 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-09-05 <b>Last modified:</b> 2009-09-06</p> 24350<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#meta.help">issues</a> in [meta.help].</p> 24351<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 24352<p><b>Discussion:</b></p> 24353<p> 24354The specification of <tt>integral_constant</tt> has been inherited 24355essentially unchanged from TR1: 24356</p> 24357 24358<blockquote><pre>template <class T, T v> 24359struct integral_constant { 24360 static const T value = v; 24361 typedef T value_type; 24362 typedef integral_constant<T,v> type; 24363}; 24364</pre></blockquote> 24365 24366<p> 24367In light of 0x language changes there are several things we might 24368consider changing, notably the form of specification for value. 24369</p> 24370 24371<p> 24372The current form requires a static data member have storage allocated 24373for it, where we could now implement without this using the new enum 24374syntax: 24375</p> 24376 24377<blockquote><pre>template <class T, T v> 24378struct integral_constant { 24379 <b>enum : T { value = v };</b> 24380 typedef T value_type; 24381 typedef integral_constant type; 24382}; 24383</pre></blockquote> 24384 24385<p> 24386The effective difference between these two implementation is: 24387</p> 24388 24389<ol type="i"> 24390<li> 24391No requirement to allocate storage for data member (which we hope but do 24392not guarantee compilers strip today) 24393</li> 24394 24395<li> 24396You can no longer take the address of the constant as 24397<tt>&integral_constant<T,v>::value;</tt> 24398</li> 24399</ol> 24400 24401<p> 24402Also note the editorial change to drop the explicit qualification of 24403<tt>integral_constant</tt> in the <tt>typedef type</tt>. This makes it quite clear we 24404mean the current instantiation, and cannot be mistaken for a recursive 24405metaprogram. 24406</p> 24407 24408<p> 24409Even if we don't mandate this implementation, it would be nice to give 24410vendors freedom under QoI to choose their preferred representation. 24411</p> 24412 24413<p> 24414The other side of this issue is if we choose to retain the static 24415constant form. In that case we should go further and insist on 24416<tt>constexpr</tt>, much like we did throughout <tt>numeric_limits</tt>: 24417</p> 24418 24419<blockquote><pre>template <class T, T v> 24420struct integral_constant { 24421 static <b>constexpr</b> T value = v; 24422 typedef T value_type; 24423 typedef integral_constant type; 24424}; 24425</pre></blockquote> 24426 24427<p> 24428[Footnote] It turns out <tt>constexpr</tt> is part of the Tentatively Ready 24429resolution for <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1019">1019</a>. I don't want to interfere with that issue, but 24430would like a new issue to consider if the fixed-base enum implementation 24431should be allowed. 24432</p> 24433 24434<p><i>[ 244352009-09-05 Daniel adds: 24436]</i></p> 24437 24438 24439<blockquote> 24440<p> 24441I think that the suggested resolution is incomplete and 24442may have some possible unwanted side-effects. To understand 24443why, note that <tt>integral_constant</tt> is <em>completely</em> specified 24444by code in 20.6.3 [meta.help]. While this is usually considered 24445as a good thing, let me give a possible user-defined 24446specialization that would break given the suggested changes: 24447</p> 24448 24449<blockquote><pre>enum NodeColor { Red, Black }; 24450 24451std::integral_constant<NodeColor, Red> red; 24452</pre></blockquote> 24453 24454<p> 24455The reason why that breaks is due to the fact that 24456current core language rules does only allow integral 24457types as enum-bases, see 7.2 [dcl.enum]/2. 24458</p> 24459 24460<p> 24461So, I think that we cannot leave the implementation the 24462freedom to decide which way they would like to provide 24463the implementation, because that is easily user-visible 24464(I don't speak of addresses, but of instantiation errors), 24465therefore if applied, this should be either specified or 24466wording must be added that gives a note about this 24467freedom of implementation. 24468</p> 24469 24470<p> 24471Another possible disadvantage seems to me that user-expectations 24472are easy to disappoint if they see a failure 24473of the test 24474</p> 24475 24476<blockquote><pre>assert(typeid(std::integral_constant<int, 0>::value) == typeid(int)); 24477</pre></blockquote> 24478 24479<p> 24480or of 24481</p> 24482 24483<blockquote><pre>static_assert(std::is_same<decltype(std::integral_constant<int, 0>::value), const int>::value, "Bad library"); 24484</pre></blockquote> 24485 24486</blockquote> 24487 24488 24489 24490<p><b>Proposed resolution:</b></p> 24491 24492 24493 24494 24495 24496<hr> 24497<h3><a name="1204"></a>1204. Global permission to move</h3> 24498<p><b>Section:</b> 17.6.3.9 [res.on.arguments] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 24499 <b>Submitter:</b> Howard Hinnant <b>Opened:</b> 2009-09-12 <b>Last modified:</b> 2009-10-20</p> 24500<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 24501<p><b>Discussion:</b></p> 24502<p> 24503When a library function binds an rvalue reference parameter to an argument, the 24504library must be able to assume that the bound argument is a temporary, and not 24505a moved-from lvalue. The reason for this is that the library function must be 24506able to modify that argument without concern that such modifications will corrupt 24507the logic of the calling code. For example: 24508</p> 24509 24510<blockquote><pre>template <class T, class A> 24511void 24512vector<T, A>::push_back(value_type&& v) 24513{ 24514 <font color="#c80000">// This function should move from v, potentially modifying</font> 24515 <font color="#c80000">// the object v is bound to.</font> 24516} 24517</pre></blockquote> 24518 24519<p> 24520If <tt>v</tt> is truly bound to a temporary, then <tt>push_back</tt> has the 24521<em>only</em> reference to this temporary in the entire program. Thus any 24522modifications will be invisible to the rest of the program. 24523</p> 24524 24525<p> 24526If the client supplies <tt>std::move(x)</tt> to <tt>push_back</tt>, the onus is 24527on the client to ensure that the value of <tt>x</tt> is no longer important to 24528the logic of his program after this statement. I.e. the client is making a statement 24529that <tt>push_back</tt> may treat <tt>x</tt> as a temporary. 24530</p> 24531 24532<blockquote><em> 24533The above statement is the very foundation upon which move semantics is based. 24534</em></blockquote> 24535 24536<p> 24537The standard is currently lacking a global statement to this effect. I propose 24538the following addition to 17.6.3.9 [res.on.arguments]: 24539</p> 24540 24541<blockquote> 24542<p> 24543Each of the following statements applies to all arguments to functions 24544defined in the C++ standard library, unless explicitly stated otherwise. 24545</p> 24546<ul> 24547<li> 24548If an argument to a function has an invalid value (such as a value 24549outside the domain of the function, or a pointer invalid for its 24550intended use), the behavior is undefined. 24551</li> 24552<li> 24553If a function argument is described as being an array, the pointer 24554actually passed to the function shall have a value such that all address 24555computations and accesses to objects (that would be valid if the pointer 24556did point to the first element of such an array) are in fact valid. 24557</li> 24558<li><ins> 24559If a function argument binds to an rvalue reference parameter, the C++ 24560standard library may assume that this parameter is a unique reference 24561to this argument. If the parameter is a generic parameter of the 24562form <tt>T&&</tt>, and an lvalue of type <tt>A</tt> is bound, 24563then the binding is considered to be to an lvalue reference 24564(14.9.2.1 [temp.deduct.call]) and thus not covered by this clause. 24565[<i>Note:</i> 24566If a program casts an lvalue to an rvalue while passing that lvalue to 24567a library function (e.g. <tt>move(x)</tt>), then the program is effectively 24568asking the library to treat that lvalue as a temporary. The library is at 24569liberty to optimize away aliasing checks which might be needed if the argument 24570were an lvalue. 24571— <i>end note</i>] 24572</ins></li> 24573</ul> 24574 24575</blockquote> 24576 24577<p> 24578Such a global statement will eliminate the need for piecemeal statements such as 2457923.2.1 [container.requirements.general]/13: 24580</p> 24581 24582<blockquote> 24583An object bound to an rvalue reference parameter of a member function of 24584a container shall not be an element of that container; no diagnostic 24585required. 24586</blockquote> 24587 24588<p> 24589Additionally this clarifies that move assignment operators need not perform the 24590traditional <tt>if (this != &rhs)</tt> test commonly found (and needed) in 24591copy assignment operators. 24592</p> 24593 24594<p><i>[ 245952009-09-13 Niels adds: 24596]</i></p> 24597 24598 24599<blockquote> 24600Note: This resolution supports the change of 27.9.1.3 [filebuf.assign]/1, 24601proposed by LWG <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#900">900</a>. 24602</blockquote> 24603 24604<p><i>[ 246052009 Santa Cruz: 24606]</i></p> 24607 24608 24609<blockquote> 24610Move to Ready. 24611</blockquote> 24612 24613 24614 24615<p><b>Proposed resolution:</b></p> 24616<p> 24617Add a bullet to 17.6.3.9 [res.on.arguments]: 24618</p> 24619 24620<blockquote> 24621<p> 24622Each of the following statements applies to all arguments to functions 24623defined in the C++ standard library, unless explicitly stated otherwise. 24624</p> 24625<ul> 24626<li> 24627If an argument to a function has an invalid value (such as a value 24628outside the domain of the function, or a pointer invalid for its 24629intended use), the behavior is undefined. 24630</li> 24631<li> 24632If a function argument is described as being an array, the pointer 24633actually passed to the function shall have a value such that all address 24634computations and accesses to objects (that would be valid if the pointer 24635did point to the first element of such an array) are in fact valid. 24636</li> 24637<li><ins> 24638If a function argument binds to an rvalue reference parameter, the C++ 24639standard library may assume that this parameter is a unique reference 24640to this argument. If the parameter is a generic parameter of the 24641form <tt>T&&</tt>, and an lvalue of type <tt>A</tt> is bound, 24642then the binding is considered to be to an lvalue reference 24643(14.9.2.1 [temp.deduct.call]) and thus not covered by this clause. 24644[<i>Note:</i> 24645If a program casts an lvalue to an rvalue while passing that lvalue to 24646a library function (e.g. <tt>move(x)</tt>), then the program is effectively 24647asking the library to treat that lvalue as a temporary. The library is at 24648liberty to optimize away aliasing checks which might be needed if the argument 24649were an lvalue. 24650— <i>end note</i>] 24651</ins></li> 24652</ul> 24653</blockquote> 24654 24655<p> 24656Delete 23.2.1 [container.requirements.general]/13: 24657</p> 24658 24659<blockquote><del> 24660An object bound to an rvalue reference parameter of a member function of 24661a container shall not be an element of that container; no diagnostic 24662required. 24663</del></blockquote> 24664 24665 24666 24667 24668 24669 24670<hr> 24671<h3><a name="1205"></a>1205. Some algorithms could more clearly document their handling of empty ranges</h3> 24672<p><b>Section:</b> 25 [algorithms] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 24673 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-09-13 <b>Last modified:</b> 2009-09-13</p> 24674<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#algorithms">active issues</a> in [algorithms].</p> 24675<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#algorithms">issues</a> in [algorithms].</p> 24676<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 24677<p><b>Discussion:</b></p> 24678<p> 24679There are a number of algorithms whose result might depend on the 24680handling of an empty range. In some cases the result is not clear, 24681while in others it would help readers to clearly mention the result 24682rather than require some subtle intuition of the supplied wording. 24683</p> 24684 24685<p> 2468625.2.1 [alg.all_of] 24687</p> 24688 24689<blockquote> 24690<i>Returns:</i> <tt>true</tt> if <tt>pred(*i)</tt> is <tt>true</tt> for every 24691iterator <tt>i</tt> in the range <tt>[first,last)</tt>, ... 24692</blockquote> 24693 24694<p> 24695What does this mean if the range is empty? 24696</p> 24697 24698<p> 24699I believe that we intend this to be <tt>true</tt> and suggest a 24700non-normative note to clarify: 24701</p> 24702 24703<p> 24704Add to p1 25.2.1 [alg.all_of]: 24705</p> 24706 24707<blockquote> 24708[<i>Note:</i> Returns <tt>true</tt> if <tt>[first,last)</tt> is empty. 24709— <i>end note</i>] 24710</blockquote> 24711 24712<p> 2471325.2.3 [alg.none_of] 24714</p> 24715 24716<blockquote> 24717<i>Returns:</i> <tt>true</tt> if <tt>pred(*i)</tt> is <tt>false</tt> for every 24718iterator <tt>i</tt> in the range <tt>[first,last)</tt>, ... 24719</blockquote> 24720 24721<p> 24722What does this mean if the range empty? 24723</p> 24724 24725<p> 24726I believe that we intend this to be <tt>true</tt> and suggest a 24727non-normative note to clarify: 24728</p> 24729 24730<p> 24731Add to p1 25.2.3 [alg.none_of]: 24732</p> 24733 24734<blockquote> 24735[<i>Note:</i> Returns <tt>true</tt> if <tt>[first,last)</tt> is empty. 24736— <i>end note</i>] 24737</blockquote> 24738 24739<p> 2474025.2.2 [alg.any_of] 24741</p> 24742 24743<p> 24744The specification for an empty range is actually fairly clear in this 24745case, but a note wouldn't hurt and would be consistent with proposals 24746for <tt>all_of</tt>/<tt>none_of</tt> algorithms. 24747</p> 24748 24749<p> 24750Add to p1 25.2.2 [alg.any_of]: 24751</p> 24752 24753<blockquote> 24754[<i>Note:</i> Returns <tt>false</tt> if <tt>[first,last)</tt> is empty. 24755— <i>end note</i>] 24756</blockquote> 24757 24758<p> 2475925.2.6 [alg.find.end] 24760</p> 24761 24762<p> 24763what does this mean if <tt>[first2,last2)</tt> is empty? 24764</p> 24765 24766<p> 24767I believe the wording suggests the algorithm should return 24768<tt>last1</tt> in this case, but am not 100% sure. Is this in fact the 24769correct result anyway? Surely an empty range should always match and the 24770naive expected result would be <tt>first1</tt>? 24771</p> 24772 24773<p> 24774My proposed wording is a note to clarify the current semantic: 24775</p> 24776 24777<p> 24778Add to p2 25.2.6 [alg.find.end]: 24779</p> 24780 24781<blockquote> 24782[<i>Note:</i> Returns <tt>last1</tt> if <tt>[first2,last2)</tt> is 24783empty. — <i>end note</i>] 24784</blockquote> 24785 24786<p> 24787I would prefer a normative wording treating empty ranges specially, but 24788do not believe we can change semantics at this point in the process, 24789unless existing implementations actually yield this result: 24790</p> 24791 24792<p> 24793Alternative wording: (NOT a note) 24794</p> 24795<p> 24796Add to p2 25.2.6 [alg.find.end]: 24797</p> 24798<blockquote> 24799Returns <tt>first1</tt> if <tt>[first2,last2)</tt> is empty. 24800</blockquote> 24801 24802<p> 2480325.2.7 [alg.find.first.of] 24804</p> 24805 24806<p> 24807The phrasing seems precise when <tt>[first2, last2)</tt> is empty, but a small 24808note to confirm the reader's understanding might still help. 24809</p> 24810 24811<p> 24812Add to p2 25.2.7 [alg.find.first.of] 24813</p> 24814<blockquote> 24815[<i>Note:</i> Returns <tt>last1</tt> if <tt>[first2,last2)</tt> is 24816empty. — <i>end note</i>] 24817</blockquote> 24818 24819<p> 2482025.2.12 [alg.search] 24821</p> 24822 24823<p> 24824What is the expected result if <tt>[first2, last2)</tt> is empty? 24825</p> 24826 24827<p> 24828I believe the wording suggests the algorithm should return <tt>last1</tt> in this 24829case, but am not 100% sure. Is this in fact the correct result anyway? 24830Surely an empty range should always match and the naive expected result 24831would be <tt>first1</tt>? 24832</p> 24833 24834<p> 24835My proposed wording is a note to clarify the current semantic: 24836</p> 24837 24838<p> 24839Add to p2 25.2.12 [alg.search]: 24840</p> 24841 24842<blockquote> 24843[<i>Note:</i> Returns <tt>last1</tt> if <tt>[first2,last2)</tt> is 24844empty. — <i>end note</i>] 24845</blockquote> 24846 24847<p> 24848Again, I would prefer a normative wording treating empty ranges 24849specially, but do not believe we can change semantics at this point in 24850the process, unless existing implementations actually yield this result: 24851</p> 24852 24853<p> 24854Alternative wording: (NOT a note) 24855</p> 24856<p> 24857Add to p2 25.2.12 [alg.search]: 24858</p> 24859 24860<blockquote> 24861Returns <tt>first1</tt> if <tt>[first2,last2)</tt> is empty. 24862</blockquote> 24863 24864<p> 2486525.3.13 [alg.partitions] 24866</p> 24867 24868<p> 24869Is an empty range partitioned or not? 24870</p> 24871 24872<p> 24873Proposed wording: 24874</p> 24875 24876<p> 24877Add to p1 25.3.13 [alg.partitions]: 24878</p> 24879 24880<blockquote> 24881[<i>Note:</i> Returns <tt>true</tt> if <tt>[first,last)</tt> is empty. 24882— <i>end note</i>] 24883</blockquote> 24884 24885<p> 2488625.4.5.1 [includes] 24887</p> 24888 24889<blockquote> 24890<i>Returns:</i> <tt>true</tt> if every element in the range 24891<tt>[first2,last2)</tt> is contained in the range 24892<tt>[first1,last1)</tt>. ... 24893</blockquote> 24894 24895<p> 24896I really don't know what this means if <tt>[first2,last2)</tt> is empty. 24897I could loosely guess that this implies empty ranges always match, and 24898my proposed wording is to clarify exactly that: 24899</p> 24900 24901<p> 24902Add to p1 25.4.5.1 [includes]: 24903</p> 24904 24905<blockquote> 24906[<i>Note:</i> Returns <tt>true</tt> if <tt>[first2,last2)</tt> is empty. 24907— <i>end note</i>] 24908</blockquote> 24909 24910<p> 2491125.4.6.2 [pop.heap] 24912</p> 24913 24914<p> 24915The effects clause is invalid if the range <tt>[first,last)</tt> is empty, unlike 24916all the other heap alogorithms. The should be called out in the 24917requirements. 24918</p> 24919 24920<p> 24921Proposed wording: 24922</p> 24923<p> 24924Revise p2 25.4.6.2 [pop.heap] 24925</p> 24926 24927<blockquote> 24928<i>Requires:</i> The range <tt>[first,last)</tt> shall be a valid 24929<ins>non-empty</ins> heap. 24930</blockquote> 24931 24932<p> 24933[Editorial] Reverse order of 25.4.6.2 [pop.heap] p1 and p2. 24934</p> 24935 24936<p> 2493725.4.7 [alg.min.max] 24938</p> 24939 24940<p> 24941<tt>minmax_element</tt> does not clearly specify behaviour for an empty 24942range in the same way that <tt>min_element</tt> and <tt>max_element</tt> do. 24943</p> 24944 24945<p> 24946Add to p31 25.4.7 [alg.min.max]: 24947</p> 24948 24949<blockquote> 24950Returns <tt>make_pair(first, first)</tt> if <tt>first == last</tt>. 24951</blockquote> 24952 24953<p> 2495425.4.8 [alg.lex.comparison] 24955</p> 24956 24957<p> 24958The wording here seems quite clear, especially with the sample algorithm 24959implementation. A note is recommended purely for consistency with the 24960rest of these issue resolutions: 24961</p> 24962 24963<p> 24964Add to p1 25.4.8 [alg.lex.comparison]: 24965</p> 24966 24967<blockquote> 24968[<i>Note:</i> An empty sequence is lexicographically less than any other 24969non-empty sequence, but not to another empty sequence. — <i>end note</i>] 24970</blockquote> 24971 24972 24973<p><b>Proposed resolution:</b></p> 24974<p> 24975Add to p1 25.2.1 [alg.all_of]: 24976</p> 24977<blockquote> 24978[<i>Note:</i> Returns <tt>true</tt> if <tt>[first,last)</tt> is empty. 24979— <i>end note</i>] 24980</blockquote> 24981 24982<p> 24983Add to p1 25.2.2 [alg.any_of]: 24984</p> 24985<blockquote> 24986[<i>Note:</i> Returns <tt>false</tt> if <tt>[first,last)</tt> is empty. 24987— <i>end note</i>] 24988</blockquote> 24989 24990<p> 24991Add to p1 25.2.3 [alg.none_of]: 24992</p> 24993<blockquote> 24994[<i>Note:</i> Returns <tt>true</tt> if <tt>[first,last)</tt> is empty. 24995— <i>end note</i>] 24996</blockquote> 24997 24998<p> 24999Add to p2 25.2.6 [alg.find.end]: 25000</p> 25001<blockquote> 25002[<i>Note:</i> Returns <tt>last1</tt> if <tt>[first2,last2)</tt> is 25003empty. — <i>end note</i>] 25004</blockquote> 25005 25006<p> 25007Add to p2 25.2.7 [alg.find.first.of] 25008</p> 25009<blockquote> 25010[<i>Note:</i> Returns <tt>last1</tt> if <tt>[first2,last2)</tt> is 25011empty. — <i>end note</i>] 25012</blockquote> 25013 25014<p> 25015Add to p2 25.2.12 [alg.search]: 25016</p> 25017<blockquote> 25018[<i>Note:</i> Returns <tt>last1</tt> if <tt>[first2,last2)</tt> is 25019empty. — <i>end note</i>] 25020</blockquote> 25021 25022<p> 25023Add to p1 25.3.13 [alg.partitions]: 25024</p> 25025<blockquote> 25026[<i>Note:</i> Returns <tt>true</tt> if <tt>[first,last)</tt> is empty. 25027— <i>end note</i>] 25028</blockquote> 25029 25030<p> 25031Add to p1 25.4.5.1 [includes]: 25032</p> 25033<blockquote> 25034[<i>Note:</i> Returns <tt>true</tt> if <tt>[first2,last2)</tt> is empty. 25035— <i>end note</i>] 25036</blockquote> 25037 25038<p> 25039Revise p2 25.4.6.2 [pop.heap] 25040</p> 25041<blockquote> 25042Requires: The range <tt>[first,last)</tt> shall be a valid 25043<ins>non-empty</ins> heap. 25044</blockquote> 25045 25046<p> 25047[Editorial] 25048</p> 25049<blockquote> 25050Reverse order of 25.4.6.2 [pop.heap] p1 and p2. 25051</blockquote> 25052 25053<p> 25054Add to p31 25.4.7 [alg.min.max]: 25055</p> 25056<blockquote> 25057Returns <tt>make_pair(first, first)</tt> if <tt>first == last</tt>. 25058</blockquote> 25059 25060<p> 25061Add to p1 25.4.8 [alg.lex.comparison]: 25062</p> 25063<blockquote> 25064[<i>Note:</i> An empty sequence is lexicographically less than any other 25065non-empty sequence, but not less than another empty sequence. — 25066<i>end note</i>] 25067</blockquote> 25068 25069 25070 25071 25072 25073 25074<hr> 25075<h3><a name="1206"></a>1206. Incorrect requires for <tt>move_backward</tt> and <tt>copy_backward</tt></h3> 25076<p><b>Section:</b> 25.3.2 [alg.move] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 25077 <b>Submitter:</b> Howard Hinnant <b>Opened:</b> 2009-09-13 <b>Last modified:</b> 2009-09-13</p> 25078<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 25079<p><b>Discussion:</b></p> 25080<p> 2508125.3.2 [alg.move], p6 says: 25082</p> 25083 25084<blockquote> 25085<pre>template<class BidirectionalIterator1, class BidirectionalIterator2> 25086 BidirectionalIterator2 25087 move_backward(BidirectionalIterator1 first, 25088 BidirectionalIterator1 last, 25089 BidirectionalIterator2 result); 25090</pre> 25091<blockquote> 25092<p>...</p> 25093<p> 25094<i>Requires:</i> <tt>result</tt> shall not be in the range 25095<tt>[first,last)</tt>. 25096</p> 25097</blockquote> 25098</blockquote> 25099 25100<p> 25101This is essentially an "off-by-one" error. 25102</p> 25103 25104<p> 25105When <tt>result == last</tt>, which 25106<em>is</em> allowed by this specification, then the range <tt>[first, last)</tt> 25107is being move assigned into the range <tt>[first, last)</tt>. The <tt>move</tt> 25108(forward) algorithm doesn't allow self move assignment, and neither should 25109<tt>move_backward</tt>. So <tt>last</tt> should be included in the range which 25110<tt>result</tt> can not be in. 25111</p> 25112 25113<p> 25114Conversely, when <tt>result == first</tt>, which <em>is not</em> allowed by this 25115specification, then the range <tt>[first, last)</tt> 25116is being move assigned into the range <tt>[first - (last-first), first)</tt>. 25117I.e. into a <em>non-overlapping</em> range. Therefore <tt>first</tt> should 25118not be included in the range which <tt>result</tt> can not be in. 25119</p> 25120 25121<p> 25122The same argument applies to <tt>copy_backward</tt> though copy assigning elements 25123to themselves (<tt>result == last</tt>) should be harmless (though is disallowed 25124by <tt>copy</tt>). 25125</p> 25126 25127 25128 25129<p><b>Proposed resolution:</b></p> 25130<p> 25131Change 25.3.2 [alg.move], p6: 25132</p> 25133 25134<blockquote> 25135<pre>template<class BidirectionalIterator1, class BidirectionalIterator2> 25136 BidirectionalIterator2 25137 move_backward(BidirectionalIterator1 first, 25138 BidirectionalIterator1 last, 25139 BidirectionalIterator2 result); 25140</pre> 25141<blockquote> 25142<p>...</p> 25143<p> 25144<i>Requires:</i> <tt>result</tt> shall not be in the range 25145<tt><del>[</del><ins>(</ins>first,last<ins>]</ins><del>)</del></tt>. 25146</p> 25147</blockquote> 25148</blockquote> 25149 25150<p> 25151Change 25.3.1 [alg.copy], p13: 25152</p> 25153 25154<blockquote> 25155<pre>template<class BidirectionalIterator1, class BidirectionalIterator2> 25156 BidirectionalIterator2 25157 copy_backward(BidirectionalIterator1 first, 25158 BidirectionalIterator1 last, 25159 BidirectionalIterator2 result); 25160</pre> 25161<blockquote> 25162<p>...</p> 25163<p> 25164<i>Requires:</i> <tt>result</tt> shall not be in the range 25165<tt><del>[</del><ins>(</ins>first,last<ins>]</ins><del>)</del></tt>. 25166</p> 25167</blockquote> 25168</blockquote> 25169 25170 25171 25172 25173 25174<hr> 25175<h3><a name="1207"></a>1207. Underspecified std::list operations?</h3> 25176<p><b>Section:</b> 23.3.4.4 [list.ops] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 25177 <b>Submitter:</b> Lo�c Joly <b>Opened:</b> 2009-09-13 <b>Last modified:</b> 2009-09-19</p> 25178<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#list.ops">active issues</a> in [list.ops].</p> 25179<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#list.ops">issues</a> in [list.ops].</p> 25180<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 25181<p><b>Discussion:</b></p> 25182<p> 25183It looks to me like some operations of <tt>std::list</tt> 25184(<tt>sort</tt>, <tt>reverse</tt>, <tt>remove</tt>, <tt>unique</tt> & 25185<tt>merge</tt>) do not specify the validity of iterators, pointers & 25186references to elements of the list after those operations. Is it implied 25187by some other text in the standard? 25188</p> 25189 25190<p> 25191I believe <tt>sort</tt> & <tt>reverse</tt> do not invalidating 25192anything, <tt>remove</tt> & <tt>unique</tt> only invalidates what 25193refers to erased elements, <tt>merge</tt> does not invalidate anything 25194(with the same precision as <tt>splice</tt> for elements who changed of 25195container). Are those assumptions correct ? 25196</p> 25197 25198 25199<p><b>Proposed resolution:</b></p> 25200 25201 25202 25203 25204 25205<hr> 25206<h3><a name="1208"></a>1208. valarray initializer_list constructor has incorrect effects</h3> 25207<p><b>Section:</b> 26.6.2.1 [valarray.cons] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Tentatively Ready</a> 25208 <b>Submitter:</b> Howard Hinnant <b>Opened:</b> 2009-09-23 <b>Last modified:</b> 2009-10-29</p> 25209<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#valarray.cons">issues</a> in [valarray.cons].</p> 25210<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20Ready">Tentatively Ready</a> status.</p> 25211<p><b>Discussion:</b></p> 25212<p> 2521326.6.2.1 [valarray.cons] says: 25214</p> 25215 25216<blockquote> 25217<pre>valarray(initializer_list<T> il); 25218</pre> 25219<blockquote> 25220<i>Effects:</i> Same as <tt>valarray(il.begin(), il.end())</tt>. 25221</blockquote> 25222</blockquote> 25223 25224<p> 25225But there is no <tt>valarray</tt> constructor taking two <tt>const T*</tt>. 25226</p> 25227 25228<p><i>[ 252292009-10-29 Howard: 25230]</i></p> 25231 25232 25233<blockquote> 25234Moved to Tentatively Ready after 6 positive votes on c++std-lib. 25235</blockquote> 25236 25237 25238<p><b>Proposed resolution:</b></p> 25239<p> 25240Change 26.6.2.1 [valarray.cons]: 25241</p> 25242 25243<blockquote> 25244<pre>valarray(initializer_list<T> il); 25245</pre> 25246<blockquote> 25247<i>Effects:</i> Same as <tt>valarray(il.begin(), il.<del>end</del><ins>size</ins>())</tt>. 25248</blockquote> 25249</blockquote> 25250 25251 25252 25253 25254 25255<hr> 25256<h3><a name="1209"></a>1209. match_results should be moveable</h3> 25257<p><b>Section:</b> 28.10.1 [re.results.const] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 25258 <b>Submitter:</b> Stephan T. Lavavej <b>Opened:</b> 2009-09-15 <b>Last modified:</b> 2009-09-21</p> 25259<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 25260<p><b>Discussion:</b></p> 25261<p> 25262In Working Draft 25263<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2914.pdf">N2914</a>, 25264<tt>match_results</tt> lacks a move constructor and move 25265assignment operator. Because it owns dynamically allocated memory, it 25266should be moveable. 25267</p> 25268 25269<p> 25270As far as I can tell, this isn't tracked by an active issue yet; Library 25271Issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#723">723</a> doesn't talk about <tt>match_results</tt>. 25272</p> 25273 25274<p><i>[ 252752009-09-21 Daniel provided wording. 25276]</i></p> 25277 25278 25279 25280<p><b>Proposed resolution:</b></p> 25281<ol> 25282<li> 25283<p> 25284Add the following member declarations to 28.10 [re.results]/3: 25285</p> 25286 25287<blockquote><pre>// 28.10.1, construct/copy/destroy: 25288explicit match_results(const Allocator& a = Allocator()); 25289match_results(const match_results& m); 25290<ins>match_results(match_results&& m);</ins> 25291match_results& operator=(const match_results& m); 25292<ins>match_results& operator=(match_results&& m);</ins> 25293~match_results(); 25294</pre></blockquote> 25295</li> 25296 25297<li> 25298<p> 25299Add the following new prototype descriptions to 28.10.1 [re.results.const] 25300using the table numbering of 25301<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2723.pdf">N2723</a>: 25302</p> 25303 25304<blockquote> 25305<pre>match_results(const match_results& m); 25306</pre> 25307 25308<blockquote> 253094 <i>Effects:</i> Constructs an object of class <tt>match_results</tt>, as a 25310copy of <tt>m</tt>. 25311</blockquote> 25312 25313<pre><ins>match_results(match_results&& m);</ins> 25314</pre> 25315 25316<blockquote> 25317<p> 25318<ins>5 <i>Effects:</i> Move-constructs an object of class <tt>match_results</tt> 25319from <tt>m</tt> satisfying the same postconditions as Table 132. Additionally 25320the stored <tt>Allocator</tt> value is move constructed from <tt>m.get_allocator()</tt>. 25321After the initialization of <tt>*this</tt> sets <tt>m</tt> to an unspecified but valid 25322state.</ins> 25323</p> 25324 25325<p> 25326<ins>6 <i>Throws:</i> Nothing if the allocator's move constructor throws nothing.</ins> 25327</p> 25328</blockquote> 25329 25330<pre>match_results& operator=(const match_results& m); 25331</pre> 25332 25333<blockquote> 253347 <i>Effects:</i> Assigns <tt>m</tt> to <tt>*this</tt>. The postconditions of this function are 25335indicated in Table 132. 25336</blockquote> 25337 25338<pre><ins>match_results& operator=(match_results&& m);</ins> 25339</pre> 25340 25341<blockquote> 25342<p> 25343<ins>8 <i>Effects:</i> Move-assigns <tt>m</tt> to <tt>*this</tt>. The postconditions of this 25344function are indicated in Table 132. After the assignment, <tt>m</tt> is in 25345a valid but unspecified state.</ins> 25346</p> 25347 25348<p> 25349<ins>9 <i>Throws:</i> Nothing.</ins> 25350</p> 25351</blockquote> 25352</blockquote> 25353</li> 25354 25355</ol> 25356 25357 25358 25359 25360 25361<hr> 25362<h3><a name="1210"></a>1210. iterator reachability should not require a container</h3> 25363<p><b>Section:</b> 24.2 [iterator.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 25364 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-09-18 <b>Last modified:</b> 2009-09-19</p> 25365<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#iterator.requirements">active issues</a> in [iterator.requirements].</p> 25366<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#iterator.requirements">issues</a> in [iterator.requirements].</p> 25367<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 25368<p><b>Discussion:</b></p> 25369<p> 25370p6 Iterator requirements 24.2 [iterator.requirements] 25371</p> 25372 25373<blockquote> 25374An iterator <tt>j</tt> is called reachable from an iterator <tt>i</tt> if and only if 25375there is a finite sequence of applications of the expression <tt>++i</tt> that 25376makes <tt>i == j</tt>. If <tt>j</tt> is reachable from <tt>i</tt>, they refer to the same 25377container. 25378</blockquote> 25379 25380<p> 25381A good example would be stream iterators, which do not refer to a 25382container. Typically, the end iterator from a range of stream iterators 25383will compare equal for many such ranges. I suggest striking the second 25384sentence. 25385</p> 25386 25387<p> 25388An alternative wording might be: 25389</p> 25390 25391<blockquote> 25392If <tt>j</tt> is reachable from <tt>i</tt>, and both <tt>i</tt> and 25393<tt>j</tt> are dereferencable iterators, then they refer to the same 25394range. 25395</blockquote> 25396 25397 25398<p><b>Proposed resolution:</b></p> 25399<p> 25400Change 24.2 [iterator.requirements], p6: 25401</p> 25402 25403<blockquote> 25404An iterator <tt>j</tt> is called <i>reachable</i> from an iterator 25405<tt>i</tt> if and only if there is a finite sequence of applications of 25406the expression <tt>++i</tt> that makes <tt>i == j</tt>. <del>If 25407<tt>j</tt> is reachable from <tt>i</tt>, they refer to the same 25408container.</del> 25409</blockquote> 25410 25411 25412 25413 25414 25415<hr> 25416<h3><a name="1211"></a>1211. move iterators should be restricted as input iterators</h3> 25417<p><b>Section:</b> 24.5.3.1 [move.iterator] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 25418 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-09-18 <b>Last modified:</b> 2009-10-26</p> 25419<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#move.iterator">issues</a> in [move.iterator].</p> 25420<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 25421<p><b>Discussion:</b></p> 25422<p> 25423I contend that while we can support both bidirectional and random access 25424traversal, the category of a move iterator should never be better than 25425<tt>input_iterator_tag</tt>. 25426</p> 25427 25428<p> 25429The contentious point is that you cannot truly have a multipass property 25430when values are moved from a range. This is contentious if you view a 25431moved-from object as still holding a valid value within the range. 25432</p> 25433 25434<p> 25435The second reason comes from the Forward Iterator requirements table: 25436</p> 25437 25438<blockquote> 25439<p> 25440Forward iterators 24.2.3 [forward.iterators] 25441</p> 25442 25443<p> 25444Table 102 -- Forward iterator requirements 25445</p> 25446 25447<blockquote> 25448For expression <tt>*a</tt> the return type is: 25449"<tt>T&</tt> if <tt>X</tt> is mutable, otherwise <tt>const T&</tt>" 25450</blockquote> 25451</blockquote> 25452 25453<p> 25454There is a similar constraint on <tt>a->m</tt>. 25455</p> 25456 25457<p> 25458There is no support for rvalue references, nor do I believe their should 25459be. Again, opinions may vary but either this table or the definition of 25460<tt>move_iterator</tt> need updating. 25461</p> 25462 25463<p> 25464Note: this requirement probably need updating anyway if we wish to 25465support proxy iterators but I am waiting to see a new working paper 25466before filing that issue. 25467</p> 25468 25469<p><i>[ 254702009-10 post-Santa Cruz: 25471]</i></p> 25472 25473 25474<blockquote> 25475Move to Open. Howard to put his rationale mentioned above into the issue 25476as a note. 25477</blockquote> 25478 25479<p><i>[ 254802009-10-26 Howard adds: 25481]</i></p> 25482 25483 25484<blockquote> 25485<p> 25486<tt>vector::insert(pos, iter, iter)</tt> is significantly more effcient when 25487<tt>iter</tt> is a random access iterator, as compared to when it is an 25488input iterator. 25489</p> 25490 25491<p> 25492When <tt>iter</tt> is an input iterator, the best algorithm 25493is to append the inserted range to the end of the <tt>vector</tt> using 25494<tt>push_back</tt>. This may involve several reallocations before the input 25495range is exhausted. After the append, then one can use <tt>std::rotate</tt> 25496to place the inserted range into the correct position in the vector. 25497</p> 25498 25499<p> 25500But when <tt>iter</tt> is a random access iterator, the best algorithm 25501is to first compute the size of the range to be inserted (<tt>last - first</tt>), 25502do a buffer reallocation if necessary, scoot existing elements in the <tt>vector</tt> 25503down to make the "hole", and then insert the new elements directly to their correct 25504place. 25505</p> 25506 25507<blockquote><b> 25508The insert-with-random-access-iterators algorithm is considerably more efficient 25509than the insert-with-input-iterators algorithm 25510</b></blockquote> 25511 25512<p> 25513Now consider: 25514</p> 25515 25516<blockquote><pre>vector<A> v; 25517<font color="#c80000">// ... build up a large vector of A ...</font> 25518vector<A> temp; 25519<font color="#c80000">// ... build up a large temporary vector of A to later be inserted ...</font> 25520typedef move_iterator<vector<A>::iterator> MI; 25521<font color="#c80000">// Now insert the temporary elements:</font> 25522v.insert(v.begin() + N, MI(temp.begin()), MI(temp.end())); 25523</pre></blockquote> 25524 25525<p> 25526A major motivation for using <tt>move_iterator</tt> in the above example is the 25527expectation that <tt>A</tt> is cheap to move but expensive to copy. I.e. the 25528customer is looking for <em>high performance</em>. If we allow <tt>vector::insert</tt> 25529to subtract two <tt>MI</tt>'s to get the distance between them, the customer enjoys 25530substantially better performance, compared to if we say that <tt>vector::insert</tt> 25531can not subtract two <tt>MI</tt>'s. 25532</p> 25533 25534<p> 25535I can find no rationale for not giving this performance boost to our customers. 25536Therefore I am strongly against restricting <tt>move_iterator</tt> to the 25537<tt>input_iterator_tag</tt> category. 25538</p> 25539 25540<p> 25541I believe that the requirement that forward 25542iterators have a dereference that returns an lvalue reference to cause unacceptable 25543pessimization. For example <tt>vector<bool>::iterator</tt> also does not return 25544a <tt>bool&</tt> on dereference. Yet I am not aware of a single vendor that 25545is willing to ship <tt>vector<bool>::iterator</tt> as an input iterator. 25546Everyone classifies it as a random access iterator. Not only does this not 25547cause any problems, it prevents significant performance problems. 25548</p> 25549 25550</blockquote> 25551 25552 25553 25554<p><b>Proposed resolution:</b></p> 25555<p> 25556Class template move_iterator 24.5.3.1 [move.iterator] 25557</p> 25558 25559<blockquote><pre>namespace std { 25560template <class Iterator> 25561class move_iterator { 25562public: 25563 ... 25564 typedef <del>typename iterator_traits<Iterator>::iterator_category</del> <ins>input_iterator_tag</ins> iterator_category; 25565</pre></blockquote> 25566 25567 25568 25569 25570 25571<hr> 25572<h3><a name="1212"></a>1212. result of post-increment/decrement operator</h3> 25573<p><b>Section:</b> 24.2 [iterator.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 25574 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-09-18 <b>Last modified:</b> 2009-09-19</p> 25575<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#iterator.requirements">active issues</a> in [iterator.requirements].</p> 25576<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#iterator.requirements">issues</a> in [iterator.requirements].</p> 25577<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 25578<p><b>Discussion:</b></p> 25579<p>Forward iterator and bidirectional iterator place different 25580requirements on the result of post-increment/decrement operator. The 25581same form should be used in each case. 25582</p> 25583 25584<p> 25585Merging row from: 25586</p> 25587 25588<blockquote><pre>Table 102 -- Forward iterator requirements 25589Table 103 -- Bidirectional iterator requirements 25590 25591 r++ : convertible to const X& 25592 r-- : convertible to const X& 25593 25594 *r++ : T& if X is mutable, otherwise const T& 25595 *r-- : convertible to T 25596</pre></blockquote> 25597 25598 25599<p><b>Proposed resolution:</b></p> 25600 25601 25602 25603 25604 25605<hr> 25606<h3><a name="1213"></a>1213. Meaning of valid and singular iterator underspecified</h3> 25607<p><b>Section:</b> 24.2 [iterator.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 25608 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2009-09-19 <b>Last modified:</b> 2009-09-19</p> 25609<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#iterator.requirements">active issues</a> in [iterator.requirements].</p> 25610<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#iterator.requirements">issues</a> in [iterator.requirements].</p> 25611<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 25612<p><b>Discussion:</b></p> 25613<p> 25614The terms <em>valid</em> iterator and <em>singular</em> aren't 25615properly defined. The fuzziness of those terms became even worse 25616after the resolution of <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#208">208</a> (including further updates by <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#278">278</a>). In 2561724.2 [iterator.requirements] as of 25618<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2723.pdf">N2723</a> 25619the standard says now: 25620</p> 25621 25622<blockquote> 25623<p> 256245 - These values are called past-the-end values. Values of an iterator <tt>i</tt> for 25625which the expression <tt>*i</tt> is defined are called dereferenceable. The library 25626never assumes that past-the-end values are dereferenceable. Iterators 25627can also have singular values that are not associated with any 25628container. [...] Results of most expressions are undefined for singular 25629values; the only exceptions are destroying an iterator that holds a 25630singular value and the assignment of a non-singular value to an iterator 25631that holds a singular value. [...] Dereferenceable values are always 25632non-singular. 25633</p> 25634 25635<p> 2563610 - An invalid iterator is an iterator that may be singular. 25637</p> 25638</blockquote> 25639 25640<p> 25641First, issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#208">208</a> intentionally removed the earlier constraint that past-the-end 25642values are always non-singular. The reason for this was to support null 25643pointers as past-the-end iterators of e.g. empty sequences. But there 25644seem to exist different views on what a singular (iterator) value is. E.g. 25645according to the <a href="http://www.sgi.com/tech/stl/trivial.html">SGI definition</a> 25646a null pointer is <em>not</em> a singular value: 25647</p> 25648 25649<blockquote> 25650Dereferenceable iterators are always nonsingular, but the converse is 25651not true. 25652For example, a null pointer is nonsingular (there are well defined operations 25653involving null pointers) even thought it is not dereferenceable. 25654</blockquote> 25655 25656<p> 25657and <a href="http://www.sgi.com/tech/stl/InputIterator.html">proceeds</a>: 25658</p> 25659 25660<blockquote> 25661An iterator is valid if it is dereferenceable or past-the-end. 25662</blockquote> 25663 25664<p> 25665Even if the standard prefers a different meaning of singular here, the 25666change was 25667incomplete, because by restricting feasible expressions of singular 25668iterators to 25669destruction and assignment isn't sufficient for a past-the-end 25670iterator: Of-course 25671it must still be equality-comparable and in general be a readable value. 25672</p> 25673 25674<p> 25675Second, the standard doesn't clearly say whether a past-the-end value is 25676a valid iterator or not. E.g. 20.8.13 [specialized.algorithms]/1 says: 25677</p> 25678 25679<blockquote> 25680In all of the following algorithms, the formal template parameter 25681<tt>ForwardIterator</tt> 25682is required to satisfy the requirements of a forward iterator (24.1.3) 25683[..], and is 25684required to have the property that no exceptions are thrown from [..], or 25685dereference of valid iterators. 25686</blockquote> 25687 25688<p> 25689The standard should make better clear what "singular pointer" and "valid 25690iterator" means. The fact that the meaning of a valid <em>value</em> 25691has a core language meaning doesn't imply that for an iterator concept 25692the term "valid iterator" has the same meaning. 25693</p> 25694 25695<p> 25696Let me add a final example: In X [allocator.concepts.members] of 25697<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2914.pdf">N2914</a> 25698we find: 25699</p> 25700 25701<blockquote><pre>pointer X::allocate(size_type n); 25702</pre> 25703 25704<blockquote> 2570511 <i>Returns:</i> a pointer to the allocated memory. [<i>Note:</i> if <tt>n == 0</tt>, the return 25706value is unspecified. —<i>end note</i>] 25707</blockquote> 25708 25709<p> 25710[..] 25711</p> 25712 25713<pre>void X::deallocate(pointer p, size_type n); 25714</pre> 25715 25716<blockquote> 25717<i>Preconditions:</i> <tt>p</tt> shall be a non-singular pointer value obtained from a call 25718to <tt>allocate()</tt> on this allocator or one that compares equal to it. 25719</blockquote> 25720</blockquote> 25721 25722<p> 25723If singular pointer value would include null pointers this make the 25724preconditions 25725unclear if the pointer value is a result of <tt>allocate(0)</tt>: Since the return value 25726is unspecified, it could be a null pointer. Does that mean that programmers 25727need to check the pointer value for a null value before calling deallocate? 25728</p> 25729 25730 25731<p><b>Proposed resolution:</b></p> 25732 25733 25734 25735 25736 25737<hr> 25738<h3><a name="1214"></a>1214. Insufficient/inconsistent key immutability requirements for associative containers</h3> 25739<p><b>Section:</b> 23.2.4 [associative.reqmts] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 25740 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2009-09-20 <b>Last modified:</b> 2009-09-20</p> 25741<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#associative.reqmts">active issues</a> in [associative.reqmts].</p> 25742<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#associative.reqmts">issues</a> in [associative.reqmts].</p> 25743<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 25744<p><b>Discussion:</b></p> 25745<p> 25746Scott Meyers' mentions on a recent posting on <a href="http://groups.google.de/group/comp.std.c++/msg/6f9160fc428bcbea">c.s.c++</a> 25747some arguments that point to an incomplete resolution 25748of <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#103">103</a> and to an inconsistency of requirements on keys in ordered and 25749unordered associative 25750containers: 25751</p> 25752 25753<blockquote> 25754<p> 257551) <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#103">103</a> introduced the term immutable without defining it in a unique manner in 2575623.2.4 [associative.reqmts]/5: 25757</p> 25758 25759<blockquote> 25760[..] Keys in an associative container are immutable. 25761</blockquote> 25762 25763<p> 25764According to conventional dictionaries immutable is an unconditional way of 25765saying that something cannot be changed. So without any further explicit 25766allowance a user <em>always</em> runs into undefined behavior if (s)he attempts 25767to modify such a key. IMO this was not the intend of the committee to resolve 25768<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#103">103</a> in that way because the comments suggest an interpretation that 25769should give any user the freedom to modify the key in an <em>explicit</em> way 25770<em>provided</em> it would not affect the sort order in that container. 25771</p> 25772 25773<p> 257742) Another observation was that surprisingly no similar 'safety guards' 25775exists against unintentional key changes for the unordered associative 25776containers, specifically there is no such requirement as in 2577723.2.4 [associative.reqmts]/6 that "both <tt>iterator</tt> and <tt>const_iterator</tt> are constant 25778iterators". But the need for such protection against unintentional 25779changes as well as the constraints in which manner any explicit 25780changes may be performed are both missing and necessary, because 25781such changes could potentially change the <em>equivalence</em> of keys that 25782is measured by the <tt>hasher</tt> and <tt>key_equal</tt>. 25783</p> 25784 25785<p> 25786I suggest to fix the unconditional wording involved with "immutable keys" 25787by at least adding a hint for the reader that users <em>may</em> perform such 25788changes in an explicit manner <em>and</em> to perform similar wording changes 25789as <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#103">103</a> did for the ordered associative containers also for the unordered 25790containers. 25791</p> 25792</blockquote> 25793 25794 25795<p><b>Proposed resolution:</b></p> 25796 25797 25798 25799 25800 25801<hr> 25802<h3><a name="1215"></a>1215. <tt>list::merge</tt> with unequal allocators</h3> 25803<p><b>Section:</b> 23.3.4.4 [list.ops] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 25804 <b>Submitter:</b> Pablo Halpern <b>Opened:</b> 2009-09-24 <b>Last modified:</b> 2009-09-24</p> 25805<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#list.ops">active issues</a> in [list.ops].</p> 25806<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#list.ops">issues</a> in [list.ops].</p> 25807<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 25808<p><b>Discussion:</b></p> 25809<p> 25810In Bellevue (I think), we passed 25811<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2525.pdf">N2525</a>, 25812which, among other things, specifies that the behavior of 25813<tt>list::splice</tt> is undefined if the allocators of the two lists 25814being spliced do not compare equal. The same rationale should apply to 25815<tt>list::merge</tt>. The intent of <tt>list::merge</tt> (AFAIK) is to 25816move nodes from one sorted <tt>list</tt> into another sorted 25817<tt>list</tt> without copying the elements. This is possible only if the 25818allocators compare equal. 25819</p> 25820 25821 25822<p><b>Proposed resolution:</b></p> 25823<p> 25824Relative to the August 2009 WP, 25825<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2857.pdf">N2857</a>, 25826change 23.3.4.4 [list.ops], 25827paragraphs 22-25 as follows: 25828</p> 25829 25830<blockquote> 25831<pre>void merge(list&& x); 25832template <class Compare> void merge(list&& x, Compare comp); 25833</pre> 25834<blockquote> 25835<p> 25836<i>Requires</i>: both the list and the argument list shall be sorted 25837according to operator< or comp. 25838</p> 25839<p> 25840<i>Effects</i>: If <tt>(&x == this)</tt> does nothing; otherwise, merges the 25841two sorted ranges <tt>[begin(), end())</tt> and <tt>[x.begin(), 25842x.end())</tt>. The result is a range in which the elements will be 25843sorted in non-decreasing order according to the ordering defined by 25844<tt>comp</tt>; that is, for every iterator <tt>i</tt>, in the range other than the 25845<tt>first</tt>, the condition <tt>comp(*i, *(i - 1)<ins>)</ins></tt> will be 25846<tt>false</tt>. 25847</p> 25848<p> 25849<i>Remarks</i>: Stable. If <tt>(&x != this)</tt> the range <tt>[x.begin(), x.end())</tt> is 25850empty after the merge. <ins>No elements are copied by this operation. 25851The behavior is undefined if <tt>this->get_allocator() != 25852x.get_allocator()</tt>.</ins> 25853</p> 25854<p> 25855<i>Complexity</i>: At most <tt>size() + x.size() - 1</tt> applications of <tt>comp</tt> 25856if <tt>(&x != this)</tt>; otherwise, no applications of <tt>comp</tt> are performed. If an 25857exception is thrown other than by a comparison there are no effects. 25858</p> 25859</blockquote> 25860</blockquote> 25861 25862 25863 25864 25865 25866<hr> 25867<h3><a name="1216"></a>1216. LWG 1066 Incomplete?</h3> 25868<p><b>Section:</b> 18.8.6 [except.nested] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 25869 <b>Submitter:</b> Pete Becker <b>Opened:</b> 2009-09-25 <b>Last modified:</b> 2009-10-20</p> 25870<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#except.nested">active issues</a> in [except.nested].</p> 25871<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#except.nested">issues</a> in [except.nested].</p> 25872<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 25873<p><b>Discussion:</b></p> 25874<p> 25875LWG <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1066">1066</a> adds <tt>[[noreturn]]</tt> to a bunch of things. 25876It doesn't add it to <tt>rethrow_nested()</tt>, which seems like an obvious 25877candidate. I've made the changes indicated in the issue, and haven't 25878changed <tt>rethrow_nested()</tt>. 25879</p> 25880 25881<p><i>[ 258822009 Santa Cruz: 25883]</i></p> 25884 25885 25886<blockquote> 25887Move to Ready. 25888</blockquote> 25889 25890 25891 25892<p><b>Proposed resolution:</b></p> 25893<p> 25894Add <tt>[[noreturn]]</tt> to <tt>rethrow_nested()</tt> in 18.8.6 [except.nested]. 25895</p> 25896 25897 25898 25899 25900 25901<hr> 25902<h3><a name="1218"></a>1218. mutex destructor synchronization</h3> 25903<p><b>Section:</b> 30.4.1 [thread.mutex.requirements] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 25904 <b>Submitter:</b> Jeffrey Yasskin <b>Opened:</b> 2009-09-30 <b>Last modified:</b> 2009-09-30</p> 25905<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#thread.mutex.requirements">active issues</a> in [thread.mutex.requirements].</p> 25906<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#thread.mutex.requirements">issues</a> in [thread.mutex.requirements].</p> 25907<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 25908<p><b>Discussion:</b></p> 25909<p> 25910If an object <tt>*o</tt> contains a mutex <tt>mu</tt> and a 25911correctly-maintained reference count <tt>c</tt>, is the following code 25912safe? 25913</p> 25914 25915<blockquote><pre>o->mu.lock(); 25916bool del = (--(o->c) == 0); 25917o->mu.unlock(); 25918if (del) { delete o; } 25919</pre></blockquote> 25920 25921<p> 25922If the implementation of <tt>mutex::unlock()</tt> can touch the mutex's 25923memory after the moment it becomes free, this wouldn't be safe, and 25924"Construction and destruction of an object of a Mutex type need not be 25925thread-safe" 30.4.1 [thread.mutex.requirements] may imply that 25926it's not safe. Still, it's useful to allow mutexes to guard reference 25927counts, and if it's not allowed, users are likely to write bugs. 25928</p> 25929 25930 25931<p><b>Proposed resolution:</b></p> 25932<p> 25933</p> 25934 25935 25936 25937 25938 25939<hr> 25940<h3><a name="1219"></a>1219. unique_lock::lock and resource_deadlock_would_occur</h3> 25941<p><b>Section:</b> 30.4.3.2.2 [thread.lock.unique.locking] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 25942 <b>Submitter:</b> Jeffrey Yasskin <b>Opened:</b> 2009-09-30 <b>Last modified:</b> 2009-09-30</p> 25943<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#thread.lock.unique.locking">active issues</a> in [thread.lock.unique.locking].</p> 25944<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#thread.lock.unique.locking">issues</a> in [thread.lock.unique.locking].</p> 25945<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 25946<p><b>Discussion:</b></p> 25947<p> 25948<tt>unique_lock::lock</tt> and friends raise 25949"<tt>resource_deadlock_would_occur</tt> -- if the current thread already 25950owns the mutex (i.e., on entry, <tt>owns</tt> is <tt>true</tt>)." 1) 25951The current thread owning a mutex is not the same as any particular 25952<tt>unique_lock::owns</tt> being <tt>true</tt>. 2) There's no need to 25953raise this exception for a <tt>recursive_mutex</tt> if <tt>owns</tt> is 25954<tt>false</tt>. 3) If <tt>owns</tt> is true, we need to raise some 25955exception or the unique_lock will lose track of whether to unlock itself 25956on destruction, but "deadlock" isn't it. For (3), s/bool owns/int 25957ownership_level/ would fix it. 25958</p> 25959 25960 25961<p><b>Proposed resolution:</b></p> 25962 25963 25964 25965 25966 25967<hr> 25968<h3><a name="1220"></a>1220. What does condition_variable wait on?</h3> 25969<p><b>Section:</b> 30.5 [thread.condition] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Tentatively Ready</a> 25970 <b>Submitter:</b> Jeffrey Yasskin <b>Opened:</b> 2009-09-30 <b>Last modified:</b> 2009-11-06</p> 25971<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#thread.condition">active issues</a> in [thread.condition].</p> 25972<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#thread.condition">issues</a> in [thread.condition].</p> 25973<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20Ready">Tentatively Ready</a> status.</p> 25974<p><b>Discussion:</b></p> 25975<p> 25976"Class <tt>condition_variable</tt> provides a condition variable that can only 25977wait on an object of type <tt>unique_lock</tt>" should say "...object of type 25978<tt>unique_lock<mutex></tt>" 25979</p> 25980 25981<p><i>[ 259822009-11-06 Howard adds: 25983]</i></p> 25984 25985 25986<blockquote> 25987Moved to Tentatively Ready after 5 positive votes on c++std-lib. 25988</blockquote> 25989 25990 25991 25992<p><b>Proposed resolution:</b></p> 25993<p> 25994Change 30.5 [thread.condition], p1: 25995</p> 25996 25997<blockquote> 25998Condition variables provide synchronization primitives used to block a 25999thread until notified by some other thread that some condition is met or 26000until a system time is reached. Class <tt>condition_variable</tt> 26001provides a condition variable that can only wait on an object of type 26002<tt>unique_lock<ins><mutex></ins></tt>, allowing maximum 26003efficiency on some platforms. Class <tt>condition_variable_any</tt> 26004provides a general condition variable that can wait on objects of 26005user-supplied lock types. 26006</blockquote> 26007 26008 26009 26010 26011 26012<hr> 26013<h3><a name="1221"></a>1221. condition_variable wording</h3> 26014<p><b>Section:</b> 30.5.1 [thread.condition.condvar] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 26015 <b>Submitter:</b> Jeffrey Yasskin <b>Opened:</b> 2009-09-30 <b>Last modified:</b> 2009-09-30</p> 26016<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#thread.condition.condvar">active issues</a> in [thread.condition.condvar].</p> 26017<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#thread.condition.condvar">issues</a> in [thread.condition.condvar].</p> 26018<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 26019<p><b>Discussion:</b></p> 26020<p> 2602130.5.1 [thread.condition.condvar] says: 26022</p> 26023 26024<blockquote> 26025<pre>~condition_variable(); 26026</pre> 26027<blockquote> 26028<i>Precondition:</i> There shall be no thread blocked on <tt>*this</tt>. 26029[<i>Note:</i> That is, all threads shall have been notified; they may 26030subsequently block on the lock specified in the wait. Beware that 26031destroying a <tt>condition_variable</tt> object while the corresponding 26032predicate is <tt>false</tt> is likely to lead to undefined behavior. 26033— <i>end note</i>] 26034</blockquote> 26035</blockquote> 26036 26037<p> 26038The text hasn't introduced the notion of a "corresponding predicate" 26039yet. 26040</p> 26041 26042 26043<p><b>Proposed resolution:</b></p> 26044 26045 26046 26047 26048 26049<hr> 26050<h3><a name="1222"></a>1222. condition_variable incorrect effects for exception safety</h3> 26051<p><b>Section:</b> 30.5 [thread.condition] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 26052 <b>Submitter:</b> Jeffrey Yasskin <b>Opened:</b> 2009-09-30 <b>Last modified:</b> 2009-09-30</p> 26053<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#thread.condition">active issues</a> in [thread.condition].</p> 26054<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#thread.condition">issues</a> in [thread.condition].</p> 26055<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 26056<p><b>Discussion:</b></p> 26057<p> 2605830.5.1 [thread.condition.condvar] says: 26059</p> 26060 26061<blockquote> 26062<pre>void wait(unique_lock<mutex>& lock); 26063</pre> 26064<blockquote> 26065<p>...</p> 26066<p> 26067<i>Effects:</i> 26068</p> 26069<ul> 26070<li>...</li> 26071<li> 26072If the function exits via an exception, <tt>lock.unlock()</tt> shall be 26073called prior to exiting the function scope. 26074</li> 26075</ul> 26076</blockquote> 26077</blockquote> 26078 26079<p> 26080Should that be <tt>lock.lock()</tt>? 26081</p> 26082 26083 26084<p><b>Proposed resolution:</b></p> 26085 26086<p> 26087Change 30.5.1 [thread.condition.condvar] p10: 26088</p> 26089 26090<blockquote> 26091<pre>void wait(unique_lock<mutex>& lock); 26092</pre> 26093<blockquote> 26094<p>...</p> 26095<p> 26096<i>Effects:</i> 26097</p> 26098<ul> 26099<li>...</li> 26100<li> 26101If the function exits via an exception, <tt>lock.<del>un</del>lock()</tt> shall be 26102called prior to exiting the function scope. 26103</li> 26104</ul> 26105</blockquote> 26106</blockquote> 26107 26108<p> 26109And make a similar change in p16, and in 30.5.2 [thread.condition.condvarany], 26110p8 and p13. 26111</p> 26112 26113 26114 26115 26116 26117 26118<hr> 26119<h3><a name="1223"></a>1223. condition_variable_any lock matching?</h3> 26120<p><b>Section:</b> 30.5.2 [thread.condition.condvarany] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 26121 <b>Submitter:</b> Jeffrey Yasskin <b>Opened:</b> 2009-09-30 <b>Last modified:</b> 2009-09-30</p> 26122<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#thread.condition.condvarany">active issues</a> in [thread.condition.condvarany].</p> 26123<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#thread.condition.condvarany">issues</a> in [thread.condition.condvarany].</p> 26124<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 26125<p><b>Discussion:</b></p> 26126<p> 26127For <tt>condition_variable_any</tt>, must all lock arguments to concurrent wait calls 26128"match" in some way, similar to the requirement in 2612930.5.1 [thread.condition.condvar] that <tt>lock.mutex()</tt> returns the same 26130value for each of the lock arguments supplied by all concurrently 26131waiting threads (via <tt>wait</tt> or <tt>timed_wait</tt>)? 26132</p> 26133 26134 26135 26136<p><b>Proposed resolution:</b></p> 26137 26138 26139 26140 26141 26142<hr> 26143<h3><a name="1224"></a>1224. condition_variable_any support for recursive mutexes?</h3> 26144<p><b>Section:</b> 30.5.2 [thread.condition.condvarany] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 26145 <b>Submitter:</b> Jeffrey Yasskin <b>Opened:</b> 2009-09-30 <b>Last modified:</b> 2009-09-30</p> 26146<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#thread.condition.condvarany">active issues</a> in [thread.condition.condvarany].</p> 26147<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#thread.condition.condvarany">issues</a> in [thread.condition.condvarany].</p> 26148<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 26149<p><b>Discussion:</b></p> 26150<p> 26151For <tt>condition_variable_any</tt>, are recursive mutexes allowed? (I think "no") 26152</p> 26153 26154 26155 26156<p><b>Proposed resolution:</b></p> 26157 26158 26159 26160 26161 26162<hr> 26163<h3><a name="1225"></a>1225. C++0x result_of issue </h3> 26164<p><b>Section:</b> 20.7.4 [func.ret] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 26165 <b>Submitter:</b> Sebastian Gesemann <b>Opened:</b> 2009-10-05 <b>Last modified:</b> 2009-10-17</p> 26166<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#func.ret">issues</a> in [func.ret].</p> 26167<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 26168<p><b>Discussion:</b></p> 26169<p> 26170I think the text about <tt>std::result_of</tt> could be a little more precise. 26171Quoting from 26172<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2960.pdf">N2960</a>... 26173</p> 26174 26175<blockquote> 26176<p> 2617720.7.4 [func.ret] Function object return types 26178</p> 26179 26180<pre>template<class> class result_of; 26181 26182template<class Fn, class... ArgTypes> 26183class result_of<Fn(ArgTypes...)> { 26184public: 26185 typedef <i>see below</i> type; 26186}; 26187</pre> 26188 26189<p> 26190Given an rvalue <tt>fn</tt> of type <tt>Fn</tt> and values <tt>t1, t2, 26191..., tN</tt> of types <tt>T1, T2, ... TN</tt> in <tt>ArgTypes</tt> 26192respectivly, the <tt>type</tt> member is the result type of the 26193expression <tt>fn(t1,t2,...,tN)</tt>. the values <tt>ti</tt> are lvalues 26194when the corresponding type <tt>Ti</tt> is an lvalue-reference type, and 26195rvalues otherwise. 26196</p> 26197</blockquote> 26198 26199<p> 26200This text doesn't seem to consider lvalue reference types for <tt>Fn</tt>. 26201Also, it's not clear whether this class template can be used for 26202"SFINAE" like <tt>std::enable_if</tt>. Example: 26203</p> 26204 26205<blockquote><pre>template<typename Fn, typename... Args> 26206typename std::result_of<Fn(Args...)>::type 26207apply(Fn && fn, Args && ...args) 26208{ 26209 // Fn may be an lvalue reference, too 26210 return std::forward<Fn>(fn)(std::forward<Args>(args)...); 26211} 26212</pre></blockquote> 26213 26214<p> 26215Either <tt>std::result_of<...></tt> can be instantiated and simply may not have 26216a typedef "<tt>type</tt>" (-->SFINAE) or instantiating the class template for 26217some type combinations will be a "hard" compile-time error. 26218</p> 26219 26220 26221<p><b>Proposed resolution:</b></p> 26222 26223<p><i>[ 26224These changes will require compiler support 26225]</i></p> 26226 26227 26228<p> 26229Change 20.7.4 [func.ret]: 26230</p> 26231 26232<blockquote><pre>template<class> class result_of; // <i>undefined</i> 26233 26234template<class Fn, class... ArgTypes> 26235class result_of<Fn(ArgTypes...)> { 26236public: 26237 <del>typedef</del> <i>see below</i> <del>type;</del> 26238}; 26239</pre> 26240 26241<p><del> 26242Given an rvalue <tt>fn</tt> of type <tt>Fn</tt> and values <tt>t1, t2, 26243..., tN</tt> of types <tt>T1, T2, ... TN</tt> in <tt>ArgTypes</tt> 26244respectivly, the <tt>type</tt> member is the result type of the 26245expression <tt>fn(t1,t2,...,tN)</tt>. the values <tt>ti</tt> are lvalues 26246when the corresponding type <tt>Ti</tt> is an lvalue-reference type, and 26247rvalues otherwise. 26248</del></p> 26249 26250<p> 26251<ins>The class template <tt>result_of</tt> shall meet the requirements of a 26252<i>TransformationTrait</i>: Given the types <tt>Fn</tt>, <tt>T1</tt>, <tt>T2</tt>, ..., <tt>TN</tt> every 26253template specialization <tt>result_of<Fn(T1,T2,...,TN)></tt> shall define the 26254member typedef type equivalent to <tt>decltype(<i>RE</i>)</tt> if and only if 26255the expression <tt><i>RE</i></tt> 26256</ins></p> 26257 26258<blockquote><pre><ins> 26259value<Fn>() ( value<T1>(), value<T2>(), ... value<TN>() ) 26260</ins></pre></blockquote> 26261 26262<p><ins> 26263would be well-formed. Otherwise, there shall be no member typedef 26264<tt>type</tt> defined. 26265</ins></p> 26266 26267</blockquote> 26268 26269<p><i>[ 26270The <tt>value<></tt> helper function is a utility Daniel Kr�gler 26271proposed in 26272<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2958.html">N2958</a>. 26273]</i></p> 26274 26275 26276 26277 26278 26279 26280<hr> 26281<h3><a name="1226"></a>1226. Incomplete changes of #890</h3> 26282<p><b>Section:</b> 30.6.2 [futures.errors] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Tentatively Ready</a> 26283 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2009-10-05 <b>Last modified:</b> 2009-10-27</p> 26284<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20Ready">Tentatively Ready</a> status.</p> 26285<p><b>Discussion:</b></p> 26286<p> 26287Defect issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#890">890</a> overlooked to adapt the <tt>future_category</tt> from 2628830.6.1 [futures.overview] and 30.6.2 [futures.errors]: 26289</p> 26290 26291<blockquote><pre>extern const error_category* const future_category; 26292</pre></blockquote> 26293 26294<p> 26295which should be similarly transformed into function form. 26296</p> 26297 26298<p><i>[ 262992009-10-27 Howard: 26300]</i></p> 26301 26302 26303<blockquote> 26304Moved to Tentatively Ready after 5 positive votes on c++std-lib. 26305</blockquote> 26306 26307 26308 26309<p><b>Proposed resolution:</b></p> 26310<ol> 26311<li> 26312<p> 26313Change in 30.6.1 [futures.overview], header <tt><future></tt> synopsis: 26314</p> 26315 26316<blockquote><pre><del>extern</del> const error_category<ins>&</ins><del>* const</del> future_category<ins>()</ins>; 26317</pre></blockquote> 26318</li> 26319 26320<li> 26321<p> 26322Change in 30.6.2 [futures.errors]: 26323</p> 26324 26325<blockquote><pre><del>extern</del> const error_category<ins>&</ins><del>* const</del> future_category<ins>()</ins>; 26326</pre> 26327 26328<blockquote> 26329<p> 26330<del>1- <tt>future_category</tt> shall point to a statically initialized object 26331of a type derived from class <tt>error_category</tt>.</del> 26332</p> 26333<p> 26334<ins>1- <i>Returns:</i> A reference to an object of a type 26335derived from class <tt>error_category</tt>.</ins> 26336</p> 26337</blockquote> 26338 26339<pre>constexpr error_code make_error_code(future_errc e); 26340</pre> 26341 26342<blockquote> 263433 <i>Returns:</i> <tt>error_code(static_cast<int>(e), 26344<del>*</del>future_category<ins>()</ins>)</tt>. 26345</blockquote> 26346 26347<pre>constexpr error_code make_error_condition(future_errc e); 26348</pre> 26349 26350<blockquote> 263514 <i>Returns:</i> <tt>error_condition(static_cast<int>(e), 26352<del>*</del>future_category<ins>()</ins>)</tt>. 26353</blockquote> 26354</blockquote> 26355</li> 26356</ol> 26357 26358 26359 26360 26361 26362<hr> 26363<h3><a name="1227"></a>1227. <tt><bitset></tt> synopsis overspecified</h3> 26364<p><b>Section:</b> 20.3.7 [template.bitset] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 26365 <b>Submitter:</b> Bo Persson <b>Opened:</b> 2009-10-05 <b>Last modified:</b> 2009-10-26</p> 26366<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#template.bitset">active issues</a> in [template.bitset].</p> 26367<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#template.bitset">issues</a> in [template.bitset].</p> 26368<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 26369<p><b>Discussion:</b></p> 26370<p> 26371The resolutions to some library defect reports, like <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#1178">1178</a> 26372requires that <tt>#includes</tt> in each synopsis should be taken 26373literally. This means that the <tt><bitset></tt> header now 26374<em>must</em> include <tt><stdexcept></tt>, even though none of the 26375exceptions are mentioned in the <tt><bitset></tt> header. 26376</p> 26377<p> 26378Many other classes are required to throw exceptions like 26379<tt>invalid_argument</tt> and <tt>out_of_range</tt>, without explicitly 26380including <tt><stdexcept></tt> in their synopsis. It is totally 26381possible for implementations to throw the needed exceptions from utility 26382functions, whose implementations are not visible in the headers. 26383</p> 26384<p> 26385I propose that <tt><stdexcept></tt> is removed from the 26386<tt><bitset></tt> header. 26387</p> 26388 26389<p><i>[ 263902009-10 Santa Cruz: 26391]</i></p> 26392 26393 26394<blockquote> 26395Moved to Ready. 26396</blockquote> 26397 26398 26399 26400<p><b>Proposed resolution:</b></p> 26401<p> 26402Change 20.3.7 [template.bitset]: 26403</p> 26404 26405<blockquote><pre>#include <cstddef> // for size_t 26406#include <string> 26407<del>#include <stdexcept> // for invalid_argument,</del> 26408 <del>// out_of_range, overflow_error</del> 26409#include <iosfwd> // for istream, ostream 26410namespace std { 26411... 26412</pre></blockquote> 26413 26414 26415 26416 26417 26418<hr> 26419<h3><a name="1228"></a>1228. User-specialized nothrow type traits</h3> 26420<p><b>Section:</b> 20.6.4.3 [meta.unary.prop] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Open">Open</a> 26421 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-10-07 <b>Last modified:</b> 2009-10-26</p> 26422<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#meta.unary.prop">active issues</a> in [meta.unary.prop].</p> 26423<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#meta.unary.prop">issues</a> in [meta.unary.prop].</p> 26424<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Open">Open</a> status.</p> 26425<p><b>Discussion:</b></p> 26426<p> 26427According to p1 20.6.2 [meta.type.synop]: 26428</p> 26429 26430<blockquote> 26431The behavior of a program that adds specializations for any of the class 26432templates defined in this subclause is undefined unless otherwise 26433specified. 26434</blockquote> 26435 26436<p> 26437I believe we should 'otherwise specify' for the nothrow traits, are 26438these are exactly the use cases where the end user actually has more 26439information than the compiler. 26440</p> 26441 26442<p><i>[ 264432009-10 Santa Cruz: 26444]</i></p> 26445 26446 26447<blockquote> 26448Moved to Open. Definitely need to give the users the ability to ensure 26449that the traits give the right answers. Unsure we want to give them the 26450ability to say this in more than one way. Believes the noexcept proposal 26451already gives this. 26452</blockquote> 26453 26454 26455 26456<p><b>Proposed resolution:</b></p> 26457<p> 26458Add the following comment: 26459</p> 26460 26461<blockquote> 26462user specialization permitted to derive from <tt>std::true_type</tt> when the 26463operation is known not to throw. 26464</blockquote> 26465 26466<p> 26467to the following traits in 20.6.4.3 [meta.unary.prop] Table 43 Type 26468property predicates. 26469</p> 26470 26471<p><i>[ 26472This may require a new Comments column 26473]</i></p> 26474 26475 26476<blockquote><pre>has_nothrow_default_constructor 26477has_nothrow_copy_constructor 26478has_nothrow_assign 26479</pre></blockquote> 26480 26481 26482 26483 26484 26485<hr> 26486<h3><a name="1231"></a>1231. <tt>weak_ptr</tt> comparisons incompletely resolved</h3> 26487<p><b>Section:</b> 20.8.15.3.5 [util.smartptr.weak.obs] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Tentatively Ready</a> 26488 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2009-10-10 <b>Last modified:</b> 2009-11-06</p> 26489<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20Ready">Tentatively Ready</a> status.</p> 26490<p><b>Discussion:</b></p> 26491<p> 26492The 26493<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2637.pdf">n2637</a> 26494paper suggested several updates of the ordering semantics of 26495<tt>shared_ptr</tt> 26496and <tt>weak_ptr</tt>, among those the explicit comparison operators of <tt>weak_ptr</tt> were 26497removed/deleted, instead a corresponding functor <tt>owner_less</tt> was added. 26498The problem 26499is that 26500<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2637.pdf">n2637</a> 26501did not clearly enough specify, how the previous wording 26502parts describing 26503the comparison semantics of <tt>weak_ptr</tt> should be removed. 26504</p> 26505 26506<p><i>[ 265072009-11-06 Howard adds: 26508]</i></p> 26509 26510 26511<blockquote> 26512Moved to Tentatively Ready after 5 positive votes on c++std-lib. 26513</blockquote> 26514 26515 26516 26517<p><b>Proposed resolution:</b></p> 26518<ol> 26519<li> 26520<p> 26521Change 20.8.15.3 [util.smartptr.weak]/2 as described, the intention is to fix 26522the now no longer valid 26523requirement that <tt>weak_ptr</tt> is <tt>LessComparable</tt> [Note the deleted comma]: 26524</p> 26525 26526<blockquote> 26527Specializations of <tt>weak_ptr</tt> shall be <tt>CopyConstructible</tt><del>,</del> 26528<ins>and</ins> <tt>CopyAssignable</tt>, 26529<del>and <tt>LessThanComparable</tt>,</del> allowing their use in standard containers. 26530</blockquote> 26531</li> 26532 26533<li> 26534<p> 26535In 20.8.15.3.5 [util.smartptr.weak.obs] remove the paragraphs 9-11 including prototype: 26536</p> 26537 26538<blockquote> 26539<del>template<class T, class U> bool operator<(const weak_ptr<T>& a, const weak_ptr<U>& b);</del> 26540 26541<p> 26542<del><i>Returns:</i> an unspecified value such that</del> 26543</p> 26544<ul> 26545<li> 26546<del><tt>operator<</tt> is a strict weak ordering as described in 25.4;</del> 26547</li> 26548<li> 26549<del>under the equivalence relation defined by <tt>operator<</tt>, <tt>!(a 26550< b) && !(b < a)</tt>, two <tt>weak_ptr</tt> instances are 26551equivalent if and only if they share ownership or are both empty.</del> 26552</li> 26553</ul> 26554 26555<p> 26556<del><i>Throws:</i> nothing.</del> 26557</p> 26558 26559<p> 26560<del>[<i>Note:</i> Allows <tt>weak_ptr</tt> objects to be used as keys in associative 26561containers. — <i>end note</i>]</del> 26562</p> 26563</blockquote> 26564</li> 26565</ol> 26566 26567 26568 26569 26570 26571<hr> 26572<h3><a name="1233"></a>1233. Missing <tt>unique_ptr</tt> signatures in synopsis</h3> 26573<p><b>Section:</b> 20.8 [memory] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">Tentatively NAD Editorial</a> 26574 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2009-10-11 <b>Last modified:</b> 2009-11-04</p> 26575<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#memory">issues</a> in [memory].</p> 26576<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20NAD%20Editorial">Tentatively NAD Editorial</a> status.</p> 26577<p><b>Discussion:</b></p> 26578<p> 26579Related to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#296">296</a>. Some <tt>unique_ptr</tt> signatures are missing 26580from the synopsis in 20.8 [memory]. 26581</p> 26582 26583<p><i>[ 265842009-11-04 Howard adds: 26585]</i></p> 26586 26587 26588<blockquote> 26589Moved to Tentatively NAD Editorial. The editor has adopted the fix. 26590</blockquote> 26591 26592 26593<p><b>Proposed resolution:</b></p> 26594<p> 26595Add in 20.8 [memory], Header <tt><memory></tt> synopsis 26596missing declarations as shown below: 26597</p> 26598 26599<blockquote><pre>// 20.8.11 Class unique_ptr: 26600template <class X> class default_delete; 26601<ins>template<class T> struct default_delete<T[]>;</ins> 26602template <class X, class D = default_delete<T>> class unique_ptr; 26603<ins>template<class T, class D> class unique_ptr<T[], D>;</ins> 26604 26605<ins>template<class T, class D> void swap(unique_ptr<T, D>& x, unique_ptr<T, D>& y);</ins> 26606 26607<ins>template<class T1, class D1, class T2, class D2> 26608bool operator==(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);</ins> 26609<ins>template<class T1, class D1, class T2, class D2> 26610bool operator!=(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);</ins> 26611<ins>template<class T1, class D1, class T2, class D2> 26612bool operator<(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);</ins> 26613<ins>template<class T1, class D1, class T2, class D2> 26614bool operator<=(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);</ins> 26615<ins>template<class T1, class D1, class T2, class D2> 26616bool operator>(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);</ins> 26617<ins>template<class T1, class D1, class T2, class D2> 26618bool operator>=(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);</ins> 26619</pre></blockquote> 26620 26621 26622 26623 26624 26625<hr> 26626<h3><a name="1234"></a>1234. "Do the right thing" and NULL</h3> 26627<p><b>Section:</b> 23.2.3 [sequence.reqmts] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 26628 <b>Submitter:</b> Matt Austern <b>Opened:</b> 2009-10-09 <b>Last modified:</b> 2009-10-13</p> 26629<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#sequence.reqmts">active issues</a> in [sequence.reqmts].</p> 26630<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#sequence.reqmts">issues</a> in [sequence.reqmts].</p> 26631<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 26632<p><b>Discussion:</b></p> 26633<p> 26634On g++ 4.2.4 (x86_64-linux-gnu), the following file gives a compile 26635error: 26636</p> 26637 26638<blockquote><pre>#include <vector> 26639void foo() { std::vector<int*> v(500l, NULL); } 26640</pre></blockquote> 26641 26642<p> 26643Is this supposed to work? 26644</p> 26645 26646<p> 26647The issue: if <tt>NULL</tt> happens to be defined as <tt>0l</tt>, this is an invocation of 26648the constructor with two arguments of the same integral type. 2664923.2.3 [sequence.reqmts]/11 says that this will behave as if the the 26650overloaded constructor 26651</p> 26652 26653<blockquote><pre>X(size_type, const value_type& = value_type(), 26654 const allocator_type& = allocator_type()) 26655</pre></blockquote> 26656 26657<p> 26658were called instead, with the arguments 26659<tt>static_cast<size_type>(first)</tt>, <tt>last</tt> and 26660<tt>alloc</tt>, respectively. However, it does not say whether this 26661actually means invoking that constructor with the exact textual form of 26662the arguments as supplied by the user, or whether the standard permits 26663an implementation to invoke that constructor with variables of the same 26664type and value as what the user passed in. In most cases this is a 26665distinction without a difference. In this particular case it does make a 26666difference, since one of those things is a null pointer constant and the 26667other is not. 26668</p> 26669 26670<p> 26671Note that an implementation based on forwarding functions will use the 26672latter interpretation. 26673</p> 26674 26675 26676<p><b>Proposed resolution:</b></p> 26677 26678 26679 26680 26681 26682<hr> 26683<h3><a name="1237"></a>1237. Constrained error_code/error_condition members</h3> 26684<p><b>Section:</b> 19.5 [syserr] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Ready</a> 26685 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2009-10-14 <b>Last modified:</b> 2009-10-26</p> 26686<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#syserr">issues</a> in [syserr].</p> 26687<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Ready">Ready</a> status.</p> 26688<p><b>Discussion:</b></p> 26689<p> 26690I'm just reflecting on the now SFINAE-constrained constructors 26691and assignment operators of <tt>error_code</tt> and <tt>error_condition</tt>: 26692</p> 26693<p> 26694These are the <em>only</em> library components that are pro-actively 26695announcing that they are using <tt>std::enable_if</tt> as constraining tool, 26696which has IMO several disadvantages: 26697</p> 26698 26699<ol> 26700<li> 26701<p> 26702With the availability of template default arguments and 26703decltype, using <tt>enable_if</tt> in C++0x standard library, seems 26704unnecessary restricting implementation freedom. E.g. there 26705should be not need for a useless specification of a dummy 26706default function argument, which only confuses the reader. 26707A more reasonable implementation could e.g. be 26708</p> 26709 26710<blockquote><pre>template <class ErrorCodeEnum 26711 class = typename enable_if<is_error_code_enum<ErrorCodeEnum>::value>::type> 26712error_code(ErrorCodeEnum e); 26713</pre></blockquote> 26714 26715<p> 26716As currently specified, the function signatures are so unreadable, 26717that errors quite easily happen, see e.g. <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1229">1229</a>. 26718</p> 26719</li> 26720 26721<li> 26722<p> 26723We have a <em>lot</em> of constrained functions in other places, that 26724now have a standard phrase that is easily understandable: 26725</p> 26726 26727<blockquote> 26728<i>Remarks:</i> This constructor/function shall participate in overload 26729resolution if and only if X. 26730</blockquote> 26731 26732<p> 26733where X describes the condition. Why should these components deviate? 26734</p> 26735</li> 26736 26737<li> 26738<p> 26739If <tt>enable_if</tt> would <em>not</em> be explicitly specified, the standard library 26740is much better prepared for the future. It would also be possible, that 26741libraries with partial support for not-yet-standard-concepts could provide 26742a much better diagnostic as is possible with <tt>enable_if</tt>. This again 26743would allow for experimental concept implementations in the wild, 26744which as a result would make concept standardization a much more 26745natural thing, similar to the way as templates were standardized 26746in C++. 26747</p> 26748 26749<p> 26750In summary: I consider it as a library defect that <tt>error_code</tt> and 26751<tt>error_condition</tt> explicitly require a dependency to <tt>enable_if</tt> and 26752do limit implementation freedom and I volunteer to prepare a 26753corresponding resolution. 26754</p> 26755</li> 26756</ol> 26757 26758<p><i>[ 267592009-10-18 Beman adds: 26760]</i></p> 26761 26762 26763<blockquote> 26764I support this proposed resolution, and thank Daniel for writing it up. 26765</blockquote> 26766 26767<p><i>[ 267682009-10 Santa Cruz: 26769]</i></p> 26770 26771 26772<blockquote> 26773Moved to Ready. 26774</blockquote> 26775 26776 26777 26778<p><b>Proposed resolution:</b></p> 26779<p><i>[ 26780Should this resolution be accepted, I recommend to resolve <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1229">1229</a> as NAD 26781]</i></p> 26782 26783 26784<ol> 26785<li> 26786<p> 26787In 19.5.2.1 [syserr.errcode.overview]/1, class <tt>error_code</tt>, 26788change as indicated: 26789</p> 26790 26791<blockquote><pre>// 19.5.2.2 constructors: 26792error_code(); 26793error_code(int val, const error_category& cat); 26794template <class ErrorCodeEnum> 26795 error_code(ErrorCodeEnum e<del>, 26796 typename enable_if<is_error_code_enum<ErrorCodeEnum>::value>::type * = 0</del>); 26797 26798// 19.5.2.3 modifiers: 26799void assign(int val, const error_category& cat); 26800template <class ErrorCodeEnum> 26801 <del>typename enable_if<is_error_code_enum<ErrorCodeEnum>::value>::type</del><ins>error_code</ins>& 26802 operator=(ErrorCodeEnum e); 26803void clear(); 26804</pre></blockquote> 26805</li> 26806 26807<li> 26808<p> 26809Change 19.5.2.2 [syserr.errcode.constructors] around the prototype before p. 7: 26810</p> 26811 26812<blockquote><pre>template <class ErrorCodeEnum> 26813error_code(ErrorCodeEnum e<del>, 26814 typename enable_if<is_error_code_enum<ErrorCodeEnum>::value>::type * = 0</del>); 26815</pre> 26816<blockquote> 26817<p> 26818<ins><i>Remarks:</i> This constructor shall not participate in overload 26819resolution, unless 26820<tt>is_error_code_enum<ErrorCodeEnum>::value == true</tt>.</ins> 26821</p> 26822</blockquote> 26823</blockquote> 26824</li> 26825 26826<li> 26827<p> 26828Change 19.5.2.3 [syserr.errcode.modifiers] around the prototype before p. 3: 26829</p> 26830 26831<blockquote><pre>template <class ErrorCodeEnum> 26832 <del>typename enable_if<is_error_code_enum<ErrorCodeEnum>::value>::type</del><ins>error_code</ins>& 26833 operator=(ErrorCodeEnum e); 26834</pre> 26835 26836<blockquote> 26837<ins><i>Remarks:</i> This operator shall not participate in overload resolution, unless 26838<tt>is_error_code_enum<ErrorCodeEnum>::value == true</tt>.</ins> 26839</blockquote> 26840</blockquote> 26841</li> 26842 26843<li> 26844<p> 26845In 19.5.3.1 [syserr.errcondition.overview]/1, class <tt>error_condition</tt>, change 26846as indicated: 26847</p> 26848 26849<blockquote><pre>// 19.5.3.2 constructors: 26850error_condition(); 26851error_condition(int val, const error_category& cat); 26852template <class ErrorConditionEnum> 26853 error_condition(ErrorConditionEnum e<del>, 26854 typename enable_if<is_error_condition_enum<ErrorConditionEnum>::type* = 0</del>); 26855 26856// 19.5.3.3 modifiers: 26857void assign(int val, const error_category& cat); 26858template<<del>typename</del><ins>class</ins> ErrorConditionEnum> 26859 <del>typename enable_if<is_error_condition_enum<ErrorConditionEnum>, error_code>::type</del><ins>error_condition</ins> & 26860 operator=( ErrorConditionEnum e ); 26861void clear(); 26862</pre></blockquote> 26863</li> 26864 26865<li> 26866<p> 26867Change 19.5.3.2 [syserr.errcondition.constructors] around the 26868prototype before p. 7: 26869</p> 26870 26871<blockquote><pre>template <class ErrorConditionEnum> 26872 error_condition(ErrorConditionEnum e<del>, 26873 typename enable_if<is_error_condition_enum<ErrorConditionEnum>::value>::type* = 0</del>); 26874</pre> 26875<blockquote> 26876<ins><i>Remarks:</i> This constructor shall not participate in overload 26877resolution, unless 26878<tt>is_error_condition_enum<ErrorConditionEnum>::value == true</tt>.</ins> 26879</blockquote> 26880</blockquote> 26881</li> 26882 26883<li> 26884<p> 26885Change 19.5.3.3 [syserr.errcondition.modifiers] around the 26886prototype before p. 3: 26887</p> 26888 26889<blockquote><pre>template <class ErrorConditionEnum> 26890 <del>typename enable_if<is_error_condition_enum<ErrorConditionEnum>::value>::type</del><ins>error_condition</ins>& 26891 operator=(ErrorConditionEnum e); 26892</pre> 26893 26894<blockquote> 26895<p> 26896<ins><i>Remarks:</i> This operator shall not participate in overload resolution, unless 26897<tt>is_error_condition_enum<ErrorConditionEnum>::value == true</tt>.</ins> 26898</p> 26899 26900<p> 26901<i>Postcondition:</i> <tt>*this == make_error_condition(e)</tt>. 26902</p> 26903 26904<p> 26905<ins><i>Returns:</i> <tt>*this</tt></ins> 26906</p> 26907</blockquote> 26908</blockquote> 26909 26910</li> 26911</ol> 26912 26913 26914 26915 26916 26917 26918<hr> 26919<h3><a name="1238"></a>1238. defining algorithms taking iterator for range</h3> 26920<p><b>Section:</b> 25 [algorithms] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Future">Tentatively NAD Future</a> 26921 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-10-15 <b>Last modified:</b> 2009-11-03</p> 26922<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#algorithms">active issues</a> in [algorithms].</p> 26923<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#algorithms">issues</a> in [algorithms].</p> 26924<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20NAD%20Future">Tentatively NAD Future</a> status.</p> 26925<p><b>Discussion:</b></p> 26926<p> 26927The library has many algorithms that take a source range represented by 26928a pair of iterators, and the start of some second sequence given by a 26929single iterator. Internally, these algorithms will produce undefined 26930behaviour if the second 'range' is not as large as the input range, but 26931none of the algorithms spell this out in Requires clauses, and there is 26932no catch-all wording to cover this in clause 17 or the front matter of 2693325. 26934</p> 26935 26936<p> 26937There was an attempt to provide such wording in paper 26938<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2944.pdf">n2944</a> 26939but this 26940seems incidental to the focus of the paper, and getting the wording of 26941this issue right seems substantially more difficult than the simple 26942approach taken in that paper. Such wording will be removed from an 26943updated paper, and hopefully tracked via the LWG issues list instead. 26944</p> 26945 26946<p> 26947It seems there are several classes of problems here and finding wording 26948to solve all in one paragraph could be too much. I suspect we need 26949several overlapping requirements that should cover the desired range of 26950behaviours. 26951</p> 26952 26953<p> 26954Motivating examples: 26955</p> 26956 26957<p> 26958A good initial example is the <tt>swap_ranges</tt> algorithm. Here there is a 26959clear requirement that <tt>first2</tt> refers to the start of a valid range at 26960least as long as the range <tt>[first1, last1)</tt>. <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2944.pdf">n2944</a> tries to solve this 26961by positing a hypothetical <tt>last2</tt> iterator that is implied by the 26962signature, and requires <tt>distance(first2,last2) < distance(first1,last1)</tt>. 26963 This mostly works, although I am uncomfortable assuming that <tt>last2</tt> is 26964clearly defined and well known without any description of how to obtain 26965it (and I have no idea how to write that). 26966</p> 26967 26968<p> 26969A second motivating example might be the <tt>copy</tt> algorithm. Specifically, 26970let us image a call like: 26971</p> 26972 26973<blockquote><pre>copy(istream_iterator<int>(is),istream_iterator(),ostream_iterator<int>(os)); 26974</pre></blockquote> 26975 26976<p> 26977In this case, our input iterators are literally simple <tt>InputIterators</tt>, 26978and the destination is a simple <tt>OutputIterator</tt>. In neither case am I 26979happy referring to <tt>std::distance</tt>, in fact it is not possible for the 26980<tt>ostream_iterator</tt> at all as it does not meet the requirements. However, 26981any wording we provide must cover both cases. Perhaps we might deduce 26982<tt>last2 == ostream_iterator<int>{}</tt>, but that might not always be valid for 26983user-defined iterator types. I can well imagine an 'infinite range' 26984that writes to <tt>/dev/null</tt> and has no meaningful <tt>last2</tt>. 26985</p> 26986 26987<p> 26988The motivating example in <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2944.pdf">n2944</a> is <tt>std::equal</tt>, and that seems to fall somewhere between the 26989two. 26990</p> 26991 26992<p> 26993Outlying examples might be <tt>partition_copy</tt> that takes two output 26994iterators, and the <tt>_n</tt> algorithms where a range is specified by a 26995specific number of iterations, rather than traditional iterator pair. 26996We should also <em>not</em> accidentally apply inappropriate constraints to 26997<tt>std::rotate</tt> which takes a third iterator that is not intended to be a 26998separate range at all. 26999</p> 27000 27001<p> 27002I suspect we want some wording similar to: 27003</p> 27004 27005<blockquote> 27006For algorithms that operate on ranges where the end iterator of the 27007second range is not specified, the second range shall contain at least 27008as many elements as the first. 27009</blockquote> 27010 27011<p> 27012I don't think this quite captures the intent yet though. I am not sure 27013if 'range' is the right term here rather than sequence. More awkwardly, 27014I am not convinced we can describe an Output sequence such as produce by 27015an <tt>ostream_iterator</tt> as "containing elements", at least not as a 27016precondition to the call before they have been written. 27017</p> 27018 27019<p> 27020Another idea was to describe require that the trailing iterator support 27021at least distance(input range) applications of <tt>operator++</tt> and may be 27022written through the same number of times if a mutable/output iterator. 27023</p> 27024 27025<p> 27026We might also consider handling the case of an output range vs. an input 27027range in separate paragraphs, if that simplifies how we describe some of 27028these constraints. 27029</p> 27030 27031<p><i>[ 270322009-11-03 Howard adds: 27033]</i></p> 27034 27035 27036<blockquote> 27037Moved to Tentatively NAD Future after 5 positive votes on c++std-lib. 27038</blockquote> 27039 27040 27041<p><b>Proposed resolution:</b></p> 27042 27043 27044 27045 27046 27047<hr> 27048<h3><a name="1239"></a>1239. Defect report</h3> 27049<p><b>Section:</b> 20.6.4.3 [meta.unary.prop] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#NAD%20Editorial">Tentatively NAD Editorial</a> 27050 <b>Submitter:</b> David Abrahams <b>Opened:</b> 2009-10-16 <b>Last modified:</b> 2009-10-26</p> 27051<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#meta.unary.prop">active issues</a> in [meta.unary.prop].</p> 27052<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#meta.unary.prop">issues</a> in [meta.unary.prop].</p> 27053<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20NAD%20Editorial">Tentatively NAD Editorial</a> status.</p> 27054<p><b>Discussion:</b></p> 27055<p> 27056Table 43 defines a number of traits that yield true for arrays of class 27057types with the trait's property, but not arrays of other types with that 27058property. For example, <tt>has_trivial_default_constructor</tt>: 27059</p> 27060 27061<blockquote> 27062<tt>T</tt> is a trivial type (3.9) or a class type with a trivial default 27063constructor (12.1) or an array of such a class type. 27064</blockquote> 27065 27066<p><i>[ 270672009-10 post-Santa Cruz: 27068]</i></p> 27069 27070 27071<blockquote> 27072<p> 27073An array of a trivial type is a trivial type. 27074</p> 27075<p> 27076Mark as Tentatively NAD Editorial. The wording is OK as is, 27077since an array of a trivial type is a trivial type, but the wording as 27078proposed might be clearer. 27079</p> 27080</blockquote> 27081 27082 27083 27084<p><b>Proposed resolution:</b></p> 27085<p> 27086Change all the traits in question following this pattern: 27087</p> 27088 27089<blockquote> 27090<tt>T</tt> is a trivial type (3.9) or a class type with a trivial default 27091 constructor (12.1)<ins>,</ins> or an array of such a <del>class</del> type. 27092</blockquote> 27093 27094<p> 27095i.e., add a comma and delete a "class." 27096</p> 27097 27098 27099 27100 27101 27102<hr> 27103<h3><a name="1240"></a>1240. Deleted comparison functions of std::function not needed</h3> 27104<p><b>Section:</b> 20.7.15.2 [func.wrap.func] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 27105 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2009-10-18 <b>Last modified:</b> 2009-10-19</p> 27106<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#func.wrap.func">issues</a> in [func.wrap.func].</p> 27107<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 27108<p><b>Discussion:</b></p> 27109<p> 27110The class template <tt>std::function</tt> contains the following member 27111declarations: 27112</p> 27113 27114<blockquote><pre>// deleted overloads close possible hole in the type system 27115template<class R2, class... ArgTypes2> 27116 bool operator==(const function<R2(ArgTypes2...)>&) = delete; 27117template<class R2, class... ArgTypes2> 27118 bool operator!=(const function<R2(ArgTypes2...)>&) = delete; 27119</pre></blockquote> 27120 27121<p> 27122The leading comment here is part of the history of <tt>std::function</tt>, which 27123was introduced with <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2002/n1402.html#undefined_operators">N1402</a>. 27124During that time no explicit conversion functions existed, and the 27125"safe-bool" idiom (based on pointers-to-member) was a popular 27126technique. The only disadvantage of this idiom was that given two 27127objects <tt>f1</tt> and <tt>f2</tt> of type <tt>std::function</tt> the expression 27128</p> 27129 27130<blockquote><pre>f1 == f2; 27131</pre></blockquote> 27132 27133<p> 27134was well-formed, just because the built-in <tt>operator==</tt> for pointer to member 27135was considered after a single user-defined conversion. To fix this, an 27136overload set of <em>undefined</em> comparison functions was added, 27137such that overload resolution would prefer those ending up in a linkage error. 27138The new language facility of deleted functions provided a much better 27139diagnostic mechanism to fix this issue. 27140</p> 27141 27142<p> 27143The central point of this issue is, that with the replacement of the 27144safe-bool idiom by explicit conversion to bool the original "hole in the 27145type system" does no longer exist and therefore the comment is wrong and 27146the superfluous function definitions should be removed as well. An 27147explicit conversion function is considered in direct-initialization 27148situations only, which indirectly contain the so-called "contextual 27149conversion to bool" (4 [conv]/3). These conversions are not considered for 27150<tt>==</tt> or <tt>!=</tt> as defined by the core language. 27151</p> 27152 27153 27154<p><b>Proposed resolution:</b></p> 27155<p> 27156In 20.7.15.2 [func.wrap.func]/1, class function change as indicated: 27157</p> 27158 27159<blockquote><pre>// 20.7.15.2.3, function capacity: 27160explicit operator bool() const; 27161 27162<del>// deleted overloads close possible hole in the type system</del> 27163<del>template<class R2, class... ArgTypes2></del> 27164 <del>bool operator==(const function<R2(ArgTypes2...)>&) = delete;</del> 27165<del>template<class R2, class... ArgTypes2></del> 27166 <del>bool operator!=(const function<R2(ArgTypes2...)>&) = delete;</del> 27167</pre></blockquote> 27168 27169 27170 27171 27172 27173<hr> 27174<h3><a name="1241"></a>1241. unique_copy needs to require EquivalenceRelation</h3> 27175<p><b>Section:</b> 25.3.9 [alg.unique] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Ready">Tentatively Ready</a> 27176 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2009-10-17 <b>Last modified:</b> 2009-10-31</p> 27177<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#alg.unique">issues</a> in [alg.unique].</p> 27178<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Tentatively%20Ready">Tentatively Ready</a> status.</p> 27179<p><b>Discussion:</b></p> 27180<p> 27181A lot of fixes were silently applied during concept-time and we should 27182not lose them again. The Requires clause of 25.3.9 [alg.unique]/5 27183doesn't mention that <tt>==</tt> and the predicate need to satisfy an 27184<tt>EquivalenceRelation</tt>, as it is correctly said for 27185<tt>unique</tt>. This was intentionally fixed during conceptification, 27186were we had: 27187</p> 27188 27189<blockquote><pre>template<InputIterator InIter, class OutIter> 27190 requires OutputIterator<OutIter, RvalueOf<InIter::value_type>::type> 27191 && EqualityComparable<InIter::value_type> 27192 && HasAssign<InIter::value_type, InIter::reference> 27193 && Constructible<InIter::value_type, InIter::reference> 27194 OutIter unique_copy(InIter first, InIter last, OutIter result); 27195 27196template<InputIterator InIter, class OutIter, 27197 EquivalenceRelation<auto, InIter::value_type> Pred> 27198 requires OutputIterator<OutIter, RvalueOf<InIter::value_type>::type> 27199 && HasAssign<InIter::value_type, InIter::reference> 27200 && Constructible<InIter::value_type, InIter::reference> 27201 && CopyConstructible<Pred> 27202 OutIter unique_copy(InIter first, InIter last, OutIter result, Pred pred); 27203</pre></blockquote> 27204 27205<p> 27206Note that EqualityComparable implied an equivalence relation. 27207</p> 27208 27209<p><i>[ 27210N.B. <tt>adjacent_find</tt> was also specified to require 27211<tt>EquivalenceRelation</tt>, but that was considered as a defect in 27212concepts, see <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#1000">1000</a> 27213]</i></p> 27214 27215 27216<p><i>[ 272172009-10-31 Howard adds: 27218]</i></p> 27219 27220 27221<blockquote> 27222Moved to Tentatively Ready after 5 positive votes on c++std-lib. 27223</blockquote> 27224 27225 27226 27227<p><b>Proposed resolution:</b></p> 27228<p> 27229Change 25.3.9 [alg.unique]/5 as indicated: 27230</p> 27231 27232<blockquote><pre>template<class InputIterator, class OutputIterator> 27233 OutputIterator 27234 unique_copy(InputIterator first, InputIterator last, OutputIterator result); 27235 27236template<class InputIterator, class OutputIterator, class BinaryPredicate> 27237 OutputIterator 27238 unique_copy(InputIterator first, InputIterator last, 27239 OutputIterator result, BinaryPredicate pred); 27240</pre> 27241<blockquote> 27242<i>Requires:</i> <ins>The comparison function shall be an equivalence 27243relation.</ins> The ranges <tt>[first,last)</tt> and 27244<tt>[result,result+(last-first))</tt> shall not overlap. The expression 27245<tt>*result = *first</tt> shall be valid. If neither 27246<tt>InputIterator</tt> nor <tt>OutputIterator</tt> meets the 27247requirements of forward iterator then the value type of 27248<tt>InputIterator</tt> shall be <tt>CopyConstructible</tt> (34) and 27249<tt>CopyAssignable</tt> (table 36). Otherwise <tt>CopyConstructible</tt> 27250is not required. 27251</blockquote> 27252</blockquote> 27253 27254 27255 27256 27257 27258<hr> 27259<h3><a name="1244"></a>1244. wait_*() in *future for synchronous functions</h3> 27260<p><b>Section:</b> 30.6 [futures] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 27261 <b>Submitter:</b> Detlef Vollmann <b>Opened:</b> 2009-10-22 <b>Last modified:</b> 2009-10-23</p> 27262<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#futures">issues</a> in [futures].</p> 27263<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 27264<p><b>Discussion:</b></p> 27265<p> 27266With the addition of <tt>async()</tt>, a <tt>future</tt> might be 27267associated with a function that is not running in a different thread but 27268is stored to by run synchronously on the <tt>get()</tt> call. It's not 27269clear what the <tt>wait()</tt> functions should do in this case. 27270</p> 27271 27272<p> 27273Suggested resolution: 27274</p> 27275 27276<p> 27277Throw an exception. 27278</p> 27279 27280 27281<p><b>Proposed resolution:</b></p> 27282 27283 27284 27285 27286 27287<hr> 27288<h3><a name="1245"></a>1245. <tt>std::hash<string></tt> & co</h3> 27289<p><b>Section:</b> 20.7.16 [unord.hash] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 27290 <b>Submitter:</b> Paolo Carlini <b>Opened:</b> 2009-10-22 <b>Last modified:</b> 2009-10-25</p> 27291<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#unord.hash">active issues</a> in [unord.hash].</p> 27292<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#unord.hash">issues</a> in [unord.hash].</p> 27293<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 27294<p><b>Discussion:</b></p> 27295<p> 27296In 20.7.16 [unord.hash], <tt>operator()</tt> is specified as 27297taking the argument by value. Moreover, it is said that <tt>operator()</tt> shall 27298not throw exceptions. 27299</p> 27300 27301<p> 27302However, for the specializations for class types, like <tt>string</tt>, <tt>wstring</tt>, 27303etc, the former requirement seems suboptimal from the performance point 27304of view (a specific PR has been filed about this in the GCC Bugzilla) 27305and, together with the latter requirement, hard if not impossible to 27306fulfill. It looks like pass by const reference should be allowed in such 27307cases. 27308</p> 27309 27310 27311<p><b>Proposed resolution:</b></p> 27312<p> 27313Add to 20.7.16 [unord.hash]/2: 27314</p> 27315 27316<blockquote> 27317<pre>namespace std { 27318 template <class T> 27319 struct hash : public std::unary_function<T, std::size_t> { 27320 std::size_t operator()(T val) const; 27321 }; 27322} 27323</pre> 27324 27325<p> 27326The return value of <tt>operator()</tt> is unspecified, except that 27327equal arguments shall yield the same result. <tt>operator()</tt> shall 27328not throw exceptions. <ins>It is also unspecified whether 27329<tt>operator()</tt> of <tt>std::hash</tt> specializations for class 27330types takes its argument by value or const reference.</ins> 27331</p> 27332</blockquote> 27333 27334 27335 27336 27337 27338<hr> 27339<h3><a name="1246"></a>1246. <tt>vector::resize()</tt> missing efficiency guarantee</h3> 27340<p><b>Section:</b> 23.3.6.2 [vector.capacity] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 27341 <b>Submitter:</b> David Abrahams <b>Opened:</b> 2009-10-24 <b>Last modified:</b> 2009-10-25</p> 27342<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#vector.capacity">issues</a> in [vector.capacity].</p> 27343<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 27344<p><b>Discussion:</b></p> 27345<p> 27346If <tt>v</tt> is a <tt>vector</tt>, I think repeated calls to 27347<tt>v.resize( v.size() + 1 )</tt> should be amortized O(1), but it's not 27348clear that's true from the text of the standard: 27349</p> 27350 27351<blockquote><pre>void resize(size_type sz); 27352</pre> 27353<blockquote> 27354<i>Effects:</i> If <tt>sz < size()</tt>, equivalent to <tt>erase(begin() + sz, end());</tt>. If 27355<tt>size() < sz</tt>, appends <tt>sz - size()</tt> default constructed elements to the 27356sequence. 27357</blockquote> 27358</blockquote> 27359 27360<p> 27361Seems to me if we used <tt>push_back</tt> instead of appends, we might be giving 27362the guarantee I'd like. Thoughts? 27363</p> 27364 27365 27366<p><b>Proposed resolution:</b></p> 27367<p> 27368In 23.3.6.2 [vector.capacity]/10, change 27369</p> 27370 27371<blockquote><pre>void resize(size_type sz); 27372</pre> 27373<blockquote> 27374<i>Effects:</i> If <tt>sz < size()</tt>, equivalent to <tt>erase(begin() + sz, end());</tt>. If 27375<tt>size() < sz</tt>, <del>appends <tt>sz - size()</tt> default constructed elements to the 27376sequence</del> 27377<ins>equivalent to <tt>sz - size()</tt> consecutive evaluations of <tt>push_back(T())</tt></ins>. 27378</blockquote> 27379</blockquote> 27380 27381 27382 27383 27384 27385 27386<hr> 27387<h3><a name="1247"></a>1247. <tt>auto_ptr</tt> is overspecified</h3> 27388<p><b>Section:</b> D.10.1 [auto.ptr] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#Review">Review</a> 27389 <b>Submitter:</b> Alisdair Meredith <b>Opened:</b> 2009-10-24 <b>Last modified:</b> 2009-11-06</p> 27390<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#auto.ptr">issues</a> in [auto.ptr].</p> 27391<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#Review">Review</a> status.</p> 27392<p><b>Discussion:</b></p> 27393<p> 27394This issue is extracted as the ongoing point-of-interest from earlier 27395issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#463">463</a>. 27396</p> 27397 27398<p> 27399<tt>auto_ptr</tt> is overspecified as the <tt>auto_ptr_ref</tt> 27400implementation detail is formally specified, and the technique is 27401observable so workarounds for compiler defects can cause a working 27402implementation of the primary <tt>auto_ptr</tt> template become 27403non-conforming. 27404</p> 27405 27406<p> 27407<tt>auto_ptr_ref</tt> is a documentation aid to describe a possible 27408mechanism to implement the class. It should be marked exposition only, 27409as per similar classes, e.g., <tt>istreambuf_iterator::proxy</tt> 27410</p> 27411 27412<p><i>[ 274132009-10-25 Daniel adds: 27414]</i></p> 27415 27416 27417<blockquote> 27418<p> 27419I wonder, whether the revised wording shouldn't be as straight as 27420for <tt>istream_buf</tt> by adding one further sentence: 27421</p> 27422 27423<blockquote> 27424An implementation is permitted to provide equivalent functionality without 27425providing a class with this name. 27426</blockquote> 27427</blockquote> 27428 27429<p><i>[ 274302009-11-06 Alisdair adds Daniel's suggestion to the proposed wording. 27431]</i></p> 27432 27433 27434<p><i>[ 274352009-11-06 Howard moves issue to Review. 27436]</i></p> 27437 27438 27439 27440 27441<p><b>Proposed resolution:</b></p> 27442<p> 27443Add the term "exposition only" in the following two places: 27444</p> 27445 27446<p> 27447Ammend D.10.1 [auto.ptr]p2: 27448</p> 27449 27450<blockquote> 27451<p> 27452<ins>The exposition only class </ins> <del>T</del><ins>t</ins>emplate <tt>auto_ptr_ref</tt> 27453holds a reference to an <tt>auto_ptr</tt>. It is used by the 27454<tt>auto_ptr</tt> conversions to allow <tt>auto_ptr</tt> objects to be 27455passed to and returned from functions. 27456<ins>An implementation is permitted to provide equivalent functionality 27457without providing a class with this name.</ins> 27458</p> 27459 27460<blockquote><pre>namespace std { 27461 template <class Y> struct auto_ptr_ref { }; <ins>// exposition only</ins> 27462</pre></blockquote> 27463</blockquote> 27464 27465 27466 27467 27468 27469<hr> 27470<h3><a name="1249"></a>1249. basic_ios default ctor</h3> 27471<p><b>Section:</b> 27.5.4.1 [basic.ios.cons] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 27472 <b>Submitter:</b> Martin Sebor <b>Opened:</b> 2009-10-25 <b>Last modified:</b> 2009-10-26</p> 27473<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#basic.ios.cons">issues</a> in [basic.ios.cons].</p> 27474<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 27475<p><b>Discussion:</b></p> 27476<p> 27477The basic_ios default ctor is required to leave the objects members 27478uninitialized (see below). The paragraph says the object must be 27479initialized by calling basic_ios::init() before it's destroyed by 27480I can't find a requirement that it be initialized before calling 27481any of the class other member functions. Am I not looking in the 27482right place or that an issue? 27483</p> 27484 27485<p><i>[ 274862009-10-25 Daniel adds: 27487]</i></p> 27488 27489 27490<blockquote> 27491<p> 27492I agree, that your wording makes that clearer, but suggest to write 27493</p> 27494 27495<blockquote> 27496... calling <tt>basic_ios::init<del>()</del></tt> before ... 27497</blockquote> 27498 27499<p> 27500Doing so, I recommend to adapt that of <tt>ios_base();</tt> as well, where 27501we have: 27502</p> 27503 27504<blockquote> 27505<i>Effects:</i> Each <tt>ios_base</tt> member has an indeterminate value 27506after construction. These members shall be initialized by calling 27507<tt>basic_ios::init</tt>. If an <tt>ios_base</tt> object is destroyed 27508before these initializations have taken place, the behavior is 27509undefined. 27510</blockquote> 27511</blockquote> 27512 27513 27514 27515<p><b>Proposed resolution:</b></p> 27516<p> 27517Change 27.5.2.7 [ios.base.cons] p1: 27518</p> 27519 27520<blockquote><pre>ios_base(); 27521</pre> 27522<blockquote> 27523<i>Effects:</i> Each <tt>ios_base</tt> member has an indeterminate value 27524after construction. <del>These</del> <ins>The object's</ins> members shall be initialized by calling 27525<tt>basic_ios::init</tt> <ins>before the object's first use or before 27526 it is destroyed, whichever comes first; otherwise the behavior 27527 is undefined.</ins>. <del>If an <tt>ios_base</tt> object is destroyed 27528before these initializations have taken place, the behavior is 27529undefined.</del> 27530</blockquote> 27531</blockquote> 27532 27533<p> 27534Change 27.5.4.1 [basic.ios.cons] p2: 27535</p> 27536 27537<blockquote><pre>basic_ios(); 27538</pre> 27539<blockquote> 27540<i>Effects:</i> Constructs an object of class <tt>basic_ios</tt> 27541(27.5.2.7) leaving its member objects uninitialized. The object shall be 27542initialized by calling <del>its</del> 27543<tt><ins>basic_ios::</ins>init</tt> <ins>before its first 27544use or before it is destroyed, whichever comes first; otherwise the 27545behavior is undefined.</ins> <del>member function. If it is destroyed 27546before it has been initialized the behavior is undefined.</del> 27547</blockquote> 27548</blockquote> 27549 27550 27551 27552 27553 27554<hr> 27555<h3><a name="1250"></a>1250. <tt><bitset></tt> still overspecified</h3> 27556<p><b>Section:</b> 20.3.7 [template.bitset] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 27557 <b>Submitter:</b> Martin Sebor <b>Opened:</b> 2009-10-29 <b>Last modified:</b> 2009-10-29</p> 27558<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#template.bitset">active issues</a> in [template.bitset].</p> 27559<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#template.bitset">issues</a> in [template.bitset].</p> 27560<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 27561<p><b>Discussion:</b></p> 27562<p> 27563Issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1227">1227</a> — <tt><bitset></tt> synopsis overspecified makes the observation 27564that <tt>std::bitset</tt>, and in fact the whole library, may be implemented 27565without needing to <tt>#include <stdexcept></tt> in any library header. The 27566proposed resolution removes the <tt>#include <stdexcept></tt> directive from 27567the header. 27568</p> 27569 27570<p> 27571I'd like to add that the <tt><bitset></tt> header (as well as the rest of 27572the library) has also been implemented without #including the 27573<tt><cstddef></tt> header in any library header. In the case of <tt>std::bitset</tt>, 27574the template is fully usable (i.e., it may be instantiated and all 27575its member functions may be used) without ever mentioning <tt>size_t</tt>. 27576In addition, just like no library header except for <tt><bitset></tt> 27577<tt>#includes <stdexcept></tt> in its synopsis, no header but <tt><bitset></tt> 27578<tt>#includes <cstddef></tt> either. 27579</p> 27580 27581<p> 27582Thus I suggest that the <tt>#include <cstddef></tt> directive be similarly 27583removed from the synopsis of <tt><bitset></tt>. 27584</p> 27585 27586 27587<p><b>Proposed resolution:</b></p> 27588<p> 27589Change 20.3.7 [template.bitset]: 27590</p> 27591 27592<blockquote><pre><del>#include <cstddef> // for size_t</del> 27593#include <string> 27594#include <iosfwd> // for istream, ostream 27595namespace std { 27596... 27597</pre></blockquote> 27598 27599 27600 27601 27602 27603<hr> 27604<h3><a name="1251"></a>1251. move constructing <tt>basic_stringbuf</tt></h3> 27605<p><b>Section:</b> 27.8.1.1 [stringbuf.cons] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 27606 <b>Submitter:</b> Martin Sebor <b>Opened:</b> 2009-10-29 <b>Last modified:</b> 2009-10-29</p> 27607<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#stringbuf.cons">issues</a> in [stringbuf.cons].</p> 27608<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 27609<p><b>Discussion:</b></p> 27610<p> 27611I just came across issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1204">1204</a> -- Global permission to move, which 27612seems to address the concern raised by the example in c++std-lib-25030. 27613</p> 27614<p> 27615IIUC, the example violates the permission to assume that arguments 27616bound to rvalue references are unnamed temporaries granted to 27617implementations by the resolution of issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1204">1204</a> - Global permission 27618to move. 27619</p> 27620 27621<p> 27622I.e., the <tt>ostringstream(ostringstream &&rhs)</tt> ctor can leave the <tt>rhs</tt> 27623pointers pointing to the newly constructed object's buffer just as 27624long as the dtor doesn't change or invalidate the buffer. The caller 27625may not make any assumptions about rhs after the move beyond it being 27626safe to destroy or reassign. 27627</p> 27628 27629<p> 27630So unless I misunderstood something, I still think the <tt>basic_stringbuf</tt> 27631move ctor is overspecified. Specifically, I think the third sentence 27632in the Effects clause and the last 6 bullets in the Postconditions 27633clause can, and IMO should, be stricken. 27634</p> 27635 27636 27637<p><b>Proposed resolution:</b></p> 27638<p> 27639Strike from 27.8.1.1 [stringbuf.cons]: 27640</p> 27641 27642<blockquote><pre>basic_stringbuf(basic_stringbuf&& rhs); 27643</pre> 27644<blockquote> 27645<p> 27646<i>Effects:</i> Move constructs from the rvalue <tt>rhs</tt>. It is 27647implementation-defined whether the sequence pointers in <tt>*this</tt> 27648(<tt>eback()</tt>, <tt>gptr()</tt>, <tt>egptr()</tt>, <tt>pbase()</tt>, 27649<tt>pptr()</tt>, <tt>epptr()</tt>) obtain the values which <tt>rhs</tt> 27650had. <del>Whether they do or not, <tt>*this</tt> and <tt>rhs</tt> reference 27651separate buffers (if any at all) after the construction.</del> The openmode, 27652locale and any other state of <tt>rhs</tt> is also copied. 27653</p> 27654 27655<p> 27656<i>Postconditions:</i> Let <tt>rhs_p</tt> refer to the state of 27657<tt>rhs</tt> just prior to this construction and let <tt>rhs_a</tt> 27658referto the state of <tt>rhs</tt> just after this construction. 27659</p> 27660<ul> 27661<li> 27662<tt>str() == rhs_p.str()</tt> 27663</li> 27664<li> 27665<tt>gptr() - eback() == rhs_p.gptr() - rhs_p.eback()</tt> 27666</li> 27667<li> 27668<tt>egptr() - eback() == rhs_p.egptr() - rhs_p.eback()</tt> 27669</li> 27670<li> 27671<tt>pptr() - pbase() == rhs_p.pptr() - rhs_p.pbase()</tt> 27672</li> 27673<li> 27674<tt>epptr() - pbase() == rhs_p.epptr() - rhs_p.pbase()</tt> 27675</li> 27676<li><del> 27677if <tt>(eback()) eback() != rhs_a.eback()</tt> 27678</del></li> 27679<li><del> 27680if <tt>(gptr()) gptr() != rhs_a.gptr()</tt> 27681</del></li> 27682<li><del> 27683if <tt>(egptr()) egptr() != rhs_a.egptr()</tt> 27684</del></li> 27685<li><del> 27686if <tt>(pbase()) pbase() != rhs_a.pbase()</tt> 27687</del></li> 27688<li><del> 27689if <tt>(pptr()) pptr() != rhs_a.pptr()</tt> 27690</del></li> 27691<li><del> 27692if <tt>(epptr()) epptr() != rhs_a.epptr()</tt> 27693</del></li> 27694</ul> 27695</blockquote> 27696</blockquote> 27697 27698 27699 27700 27701 27702 27703<hr> 27704<h3><a name="1252"></a>1252. <tt>wbuffer_convert::state_type</tt> inconsistency</h3> 27705<p><b>Section:</b> 22.3.3.2.3 [conversions.buffer] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 27706 <b>Submitter:</b> Bo Persson <b>Opened:</b> 2009-10-21 <b>Last modified:</b> 2009-10-31</p> 27707<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 27708<p><b>Discussion:</b></p> 27709<p> 27710The synopisis for <tt>wbuffer_convert</tt> 22.3.3.2.3 [conversions.buffer]/2 contains 27711</p> 27712 27713<blockquote><pre>typedef typename Tr::state_type state_type; 27714</pre></blockquote> 27715 27716<p> 27717making <tt>state_type</tt> a synonym for (possibly) some 27718<tt>char_traits<x>::state_type</tt>. 27719</p> 27720 27721<p> 27722However, in paragraph 9 of the same section, we have 27723</p> 27724 27725<blockquote><pre>typedef typename Codecvt::state_type state_type; 27726</pre> 27727 27728<blockquote> 27729The type shall be a synonym for <tt>Codecvt::state_type</tt>. 27730</blockquote> 27731</blockquote> 27732 27733<p> 27734From what I can see, it might be hard to implement 27735<tt>wbuffer_convert</tt> if the types were not both 27736<tt>std::mbstate_t</tt>, but I cannot find a requirement that they must 27737be the same type. 27738</p> 27739 27740 27741<p><b>Proposed resolution:</b></p> 27742 27743 27744 27745 27746 27747<hr> 27748<h3><a name="1253"></a>1253. invalidation of iterators and <tt>emplace</tt> vs. <tt>insert</tt> inconsistence in assoc. containers</h3> 27749<p><b>Section:</b> 23.2.4 [associative.reqmts] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 27750 <b>Submitter:</b> Boris Dušek <b>Opened:</b> 2009-10-24 <b>Last modified:</b> 2009-10-31</p> 27751<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#associative.reqmts">active issues</a> in [associative.reqmts].</p> 27752<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#associative.reqmts">issues</a> in [associative.reqmts].</p> 27753<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 27754<p><b>Discussion:</b></p> 27755<p> 27756In the latest published draft 27757<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2960.pdf">N2960</a>, 27758section 23.2.4 [associative.reqmts], paragraph 8, it is specifies 27759that that <tt>insert</tt> does not invalidate any iterators. As per 2776023.2.1 [container.requirements.general], paragraph 12, this holds 27761true not only for <tt>insert</tt>, but <tt>emplace</tt> as well. This 27762gives the <tt>insert</tt> member a special treatment w.r.t. 27763<tt>emplace</tt> member in 23.2.4 [associative.reqmts], par. 8, 27764since both modify the container. For the sake of consistency, in 23.2.4 [associative.reqmts], par. 8: either reference to 27765<tt>insert</tt> should be removed (i.e. count on 23.2.1 [container.requirements.general], par. 12), or reference to 27766<tt>emplace</tt> be added (i.e. mention all members of assoc. containers 27767that modify it). 27768</p> 27769 27770 27771<p><b>Proposed resolution:</b></p> 27772<p> 27773</p> 27774 27775 27776 27777 27778 27779<hr> 27780<h3><a name="1254"></a>1254. Misleading sentence in <tt>vector<bool>::flip</tt></h3> 27781<p><b>Section:</b> 23.3.7 [vector.bool] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 27782 <b>Submitter:</b> Christopher Jefferson <b>Opened:</b> 2009-11-01 <b>Last modified:</b> 2009-11-01</p> 27783<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#vector.bool">issues</a> in [vector.bool].</p> 27784<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 27785<p><b>Discussion:</b></p> 27786<p> 27787The effects of <tt>vector<bool>::flip</tt> has the line: 27788</p> 27789 27790<blockquote> 27791It is unspecified whether the function has any effect on allocated but 27792unused bits. 27793</blockquote> 27794 27795<p> 27796While this is technically true, it is misleading, as any member function 27797in any standard container may change unused but allocated memory. Users 27798can never observe such changes as it would also be undefined behaviour 27799to read such memory. 27800</p> 27801 27802 27803<p><b>Proposed resolution:</b></p> 27804<p> 27805Strike second sentence from the definition of <tt>vector<bool>::flip()</tt>, 2780623.3.7 [vector.bool], paragraph 5. 27807</p> 27808 27809<blockquote> 27810<i>Effects:</i> Replaces each element in the container with its complement. 27811<del>It is unspecified whether the function has any effect on allocated 27812but unused bits.</del> 27813</blockquote> 27814 27815 27816 27817 27818 27819<hr> 27820<h3><a name="1255"></a>1255. <tt>declval</tt> should be added to the library</h3> 27821<p><b>Section:</b> 20.3 [utility] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 27822 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2009-11-03 <b>Last modified:</b> 2009-11-04</p> 27823<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 27824<p><b>Discussion:</b></p> 27825<p> 27826During the Santa Cruz meeting it was decided to split off the provision 27827of the library utility <tt>value()</tt> proposed in <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2979.html">N2979</a> 27828from the concrete request of the 27829<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2939.html#uk300">UK 300</a> 27830comment. 27831The provision of a new library component that allows the production of 27832values in unevaluated expressions is considered as important 27833to realize constrained templates in C++0x where concepts are not 27834available. 27835</p> 27836 27837<p> 27838The following proposed resolution is an improvement over that suggested in 27839<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2958.html">N2958</a>, 27840because the proposed component can now be defined without loss of 27841general usefulness and any <i>use</i> by user-code will make the program ill-formed. 27842A possible prototype implementation that satisfies the core language 27843requirements 27844can be written as: 27845</p> 27846 27847<blockquote><pre>template<class T> 27848 struct declval_protector { 27849 static const bool stop = false; 27850 static typename std::add_rvalue_reference<T>::type delegate(); <font color="#c80000">// undefined</font> 27851 }; 27852 27853template<class T> 27854typename std::add_rvalue_reference<T>::type declval() { 27855 static_assert(declval_protector<T>::stop, "declval() must not be used!"); 27856 return declval_protector<T>::delegate(); 27857} 27858</pre></blockquote> 27859 27860<p> 27861Further-on the earlier suggested name <tt>value()</tt> has been changed to <tt>declval()</tt> 27862after discussions with committee members. 27863</p> 27864 27865<p> 27866Finally the suggestion shown below demonstrates that it can simplify 27867existing standard wording by directly using it in the library 27868specification, and that it also improves an overlooked corner case for 27869<tt>common_type</tt> by adding support for <tt>cv void</tt>. 27870</p> 27871 27872 27873<p><b>Proposed resolution:</b></p> 27874<p><i>[ 27875The following edit assumes that the earlier component identity 27876has been removed as part of applying the solution of <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#939">939</a>, 27877<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2951.html">N2951</a>, 27878and 27879<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2984.html">N2984</a>. 27880Note that the proposal does not depend on this application, 27881but it just simplifies the editorial representation 27882]</i></p> 27883 27884 27885<ol> 27886<li> 27887<p> 27888Change 20.3 [utility], header <tt><utility></tt> synopsis 27889as indicated: 27890</p> 27891 27892<blockquote><pre>// 20.3.2, forward/move: 27893template <class T, class U> T&& forward(U&& u);; 27894template <class T> typename remove_reference<T>::type&& move(T&&); 27895 27896<ins>// 20.3.3, declval:</ins> 27897<ins>template <class T> typename add_rvalue_reference<T>::type declval(); // for unused context</ins> 27898</pre></blockquote> 27899</li> 27900 27901<li> 27902<p> 27903Immediately after the current section 20.3.3 [forward] insert a 27904new section: 27905</p> 27906<p> 27907<ins>20.3.3 Function template declval [declval]</ins> 27908</p> 27909<p> 27910<ins>The library provides the function template <tt>declval</tt> to simplify 27911the definition of expressions in 27912unevaluated and unused contexts (3.2 [basic.def.odr], 5 [expr]). The 27913template parameter <tt>T</tt> of <tt>declval</tt> may 27914be an incomplete type.</ins> 27915</p> 27916 27917<pre><ins>template <class T> typename add_rvalue_reference<T>::type declval(); // for unused context</ins> 27918</pre> 27919 27920<blockquote> 27921<p> 27922<ins><i>Remarks:</i> If this function is used according to 3.2 [basic.def.odr], 27923the program shall be ill-formed.</ins> 27924</p> 27925 27926<p> 27927<ins>[<i>Example:</i></ins> 27928</p> 27929 27930<blockquote><pre><ins> 27931template<class To, class From> 27932decltype(static_cast<To>(declval<From>())) convert(From&&); 27933</ins></pre></blockquote> 27934 27935<p> 27936<ins> 27937declares a function template <tt>convert</tt>, which does only participate in 27938overloading, if the type <tt>From</tt> can be 27939explicitly casted to type <tt>To</tt> — <i>end example</i>]</ins> 27940</p> 27941</blockquote> 27942 27943</li> 27944 27945<li> 27946<p> 27947This bullet just makes clear that after applying <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n2984.html">N2984</a>, the changes in 20.6.4.3 [meta.unary.prop], before 27948table Type property queries should <em>not</em> use <tt>declval</tt>, 27949because the well-formedness requirement of the specification of 27950<tt>is_constructible</tt> would become more complicated, because we 27951would need to make sure that the expression <i>CE</i> is checked in an 27952unevaluated context. 27953</p> 27954</li> 27955 27956<li> 27957<p> 27958Also 20.6.5 [meta.rel]/4 is not modified similar to the previous bullet, 27959because with 27960the stricter requirements of not using <tt>declval()</tt> the well-formedness condition 27961would be harder to specify. The following changes are only editorial ones (e.g. 27962the removal of the duplicate declaration of <tt>create()</tt>): 27963</p> 27964 27965<blockquote> 27966<p> 27967Given the following function prototype: 27968</p> 27969 27970<blockquote><pre>template <class T> 27971 typename add_rvalue_reference<T>::type create(); 27972</pre></blockquote> 27973 27974<p> 27975the predicate condition for a template specialization 27976<tt>is_convertible<From, To></tt> shall be satisfied if and only 27977if the return expression in the following code would be well-formed, 27978including any 27979im<del>m</del>plicit conversions to the return type of the function: 27980</p> 27981 27982<blockquote><pre><del>template <class T> 27983typename add_rvalue_reference<T>::type create();</del> 27984To test() { 27985 return create<From>(); 27986} 27987</pre></blockquote> 27988</blockquote> 27989</li> 27990 27991<li> 27992<p> 27993Change the entry in column "Comments" for <tt>common_type</tt> in Table 51 — 27994Other transformations (20.6.7 [meta.trans.other]): 27995</p> 27996 27997<p><i>[ 27998NB: This wording change extends the type domain of <tt>common_type</tt> for <tt>cv 27999void => cv void</tt> transformations and thus makes <tt>common_type</tt> usable for 28000all binary type combinations that are supported by <tt>is_convertible</tt> 28001]</i></p> 28002 28003 28004<blockquote> 28005The member typedef <tt>type</tt> shall be defined as set out below. All 28006types in the parameter pack <tt>T</tt> shall be complete <ins>or 28007(possibly cv-qualified) <tt>void</tt></ins>. A program may specialize 28008this trait if at least one template parameter in the specialization is a 28009user-defined type. [<i>Note:</i> Such specializations are needed when 28010only explicit conversions are desired among the template arguments. 28011— <i>end note</i>] 28012</blockquote> 28013</li> 28014 28015<li> 28016<p> 28017Change 20.6.7 [meta.trans.other]/3 as indicated: 28018</p> 28019 28020<p><i>[ 28021NB: This wording change is more than an editorial simplification of 28022the definition of <tt>common_type</tt>: It also extends its usefulness for <tt>cv 28023void</tt> types as outlined above 28024]</i></p> 28025 28026 28027<blockquote> 28028<p> 28029The nested typedef <tt>common_type::type</tt> shall be defined as follows: 28030</p> 28031 28032<blockquote> 28033<p> 28034[..] 28035</p> 28036<pre>template <class T, class U> 28037struct common_type<T, U> { 28038<del>private: 28039 static T&& __t(); 28040 static U&& __u(); 28041public:</del> 28042 typedef decltype(true ? <del>__t</del><ins>declval<T></ins>() : <del>__u</del><ins>declval<U></ins>()) type; 28043}; 28044</pre> 28045</blockquote> 28046</blockquote> 28047</li> 28048</ol> 28049 28050 28051 28052 28053 28054 28055<hr> 28056<h3><a name="1256"></a>1256. <tt>weak_ptr</tt> comparison functions should be removed</h3> 28057<p><b>Section:</b> 20.8.15.3 [util.smartptr.weak] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 28058 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2009-11-04 <b>Last modified:</b> 2009-11-04</p> 28059<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 28060<p><b>Discussion:</b></p> 28061<p> 28062Additional to the necessary cleanup of the description of the the 28063<tt>weak_ptr</tt> component from 20.8.15.3 [util.smartptr.weak] 28064described in <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1231">1231</a> it turns out that the currently deleted 28065comparison functions of <tt>weak_ptr</tt> are not needed at all: There 28066is no safe-bool conversion from <tt>weak_ptr</tt>, and it won't silently 28067chose a conversion to <tt>shared_ptr</tt>. 28068</p> 28069 28070 28071<p><b>Proposed resolution:</b></p> 28072<p> 28073Change 20.8.15.3 [util.smartptr.weak]/1 as indicated: 28074</p> 28075 28076<blockquote><pre>namespace std { 28077template<class T> class weak_ptr { 28078public: 28079... 28080 <del>// comparisons</del> 28081 <del>template<class Y> bool operator<(weak_ptr<Y> const&) const = delete;</del> 28082 <del>template<class Y> bool operator<=(weak_ptr<Y> const&) const = delete;</del> 28083 <del>template<class Y> bool operator>(weak_ptr<Y> const&) const = delete;</del> 28084 <del>template<class Y> bool operator>=(weak_ptr<Y> const&) const = delete;</del> 28085}; 28086... 28087</pre></blockquote> 28088 28089 28090 28091 28092 28093<hr> 28094<h3><a name="1257"></a>1257. Header <ios> still contains a <code>concept_map</code></h3> 28095<p><b>Section:</b> 27.5 [iostreams.base] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 28096 <b>Submitter:</b> Beman Dawes <b>Opened:</b> 2009-11-04 <b>Last modified:</b> 2009-11-04</p> 28097<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#iostreams.base">issues</a> in [iostreams.base].</p> 28098<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 28099<p><b>Discussion:</b></p> 28100<p> 28101The current WP still contains a <tt>concept_map</tt>. 28102</p> 28103 28104 28105<p><b>Proposed resolution:</b></p> 28106<p> 28107Change Iostreams base classes 27.5 [iostreams.base], Header <ios> synopsis, 28108as indicated: 28109</p> 28110 28111<blockquote><pre><del>concept_map ErrorCodeEnum<io_errc> { };</del> 28112<ins>template <> struct is_error_code_enum<io_errc> : true_type { }</ins> 28113error_code make_error_code(io_errc e); 28114error_condition make_error_condition(io_errc e); 28115const error_category& iostream_category(); 28116</pre></blockquote> 28117 28118 28119 28120 28121 28122 28123<hr> 28124<h3><a name="1258"></a>1258. std::function Effects clause impossible to satisfy</h3> 28125<p><b>Section:</b> 20.7.15.2.2 [func.wrap.func.mod] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 28126 <b>Submitter:</b> Daniel Kr�gler <b>Opened:</b> 2009-11-05 <b>Last modified:</b> 2009-11-05</p> 28127<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 28128<p><b>Discussion:</b></p> 28129<p> 28130As of 20.7.15.2.2 [func.wrap.func.mod]/2+ we have the following 28131prototype description: 28132</p> 28133 28134<blockquote><pre>template<class F, Allocator Alloc> 28135 requires Callable<F, ArgTypes...> 28136 && Convertible<Callable<F, ArgTypes...>::result_type, R> 28137 void assign(F, const Alloc&); 28138</pre> 28139<blockquote> 28140<i>Effects:</i> <tt>function(f, a).swap(*this)</tt> 28141</blockquote> 28142</blockquote> 28143 28144<p> 28145Two things: First the concept debris needs to be removed, second and 28146much more importantly, the effects clause is now impossible to satisfy, 28147because there is no constructor that would match the parameter sequence 28148(<tt>FunctionObject</tt>, <tt>Allocator</tt>) [plus the fact that no 28149<tt>f</tt> and no <tt>a</tt> is part of the signature]. The most 28150probable candidate is 28151</p> 28152 28153<blockquote><pre>template<class F, class A> function(allocator_arg_t, const A&, F); 28154</pre></blockquote> 28155 28156<p> 28157and the effects clause needs to be adapted to use this signature. 28158</p> 28159 28160 28161<p><b>Proposed resolution:</b></p> 28162<p> 28163Change in 20.7.15.2.2 [func.wrap.func.mod] the complete prototype description as 28164indicated 28165</p> 28166<p><i>[ 28167Question to 28168the editor: Shouldn't there a paragraph number in front of the Effects clause? 28169]</i></p> 28170 28171 28172<blockquote><pre><del>template<class F, Allocator Alloc> 28173 requires Callable<F, ArgTypes...> 28174 && Convertible<Callable<F, ArgTypes...>::result_type, R> 28175 void assign(F, const Alloc&);</del> 28176<ins>template<class F, class A> void assign(F f, const A& a);</ins> 28177</pre> 28178<blockquote> 28179<ins>3</ins> <i>Effects:</i> <tt>function(<del>f, a</del><ins>allocator_arg, a, 28180f</ins>).swap(*this)</tt> 28181</blockquote> 28182</blockquote> 28183 28184 28185 28186 28187 28188<hr> 28189<h3><a name="1259"></a>1259. Should initializer-list constructors move elements?</h3> 28190<p><b>Section:</b> 23.2.3 [sequence.reqmts] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 28191 <b>Submitter:</b> Sean Hunt <b>Opened:</b> 2009-11-05 <b>Last modified:</b> 2009-11-06</p> 28192<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#sequence.reqmts">active issues</a> in [sequence.reqmts].</p> 28193<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#sequence.reqmts">issues</a> in [sequence.reqmts].</p> 28194<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 28195<p><b>Discussion:</b></p> 28196<p> 28197According to 23.2.3 [sequence.reqmts], <tt>X(il)</tt> is 28198equivalent to <tt>X(il.begin(), il.end())</tt>. Should it instead be 28199equivalent to <tt>X(move_iterator(il.begin()), 28200move_iterator(il.end()))</tt> so that needless copies are not made? This 28201doesn't seem ideal either - it may make more sense to provide two 28202overloads for the constructor, one for move and one for copy. 28203</p> 28204 28205 28206<p><b>Proposed resolution:</b></p> 28207<p> 28208</p> 28209 28210 28211 28212 28213 28214<hr> 28215<h3><a name="1260"></a>1260. <tt>is_constructible<int*,void*></tt> reports true</h3> 28216<p><b>Section:</b> 20.6.4.3 [meta.unary.prop] <b>Status:</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#New">New</a> 28217 <b>Submitter:</b> Peter Dimov <b>Opened:</b> 2009-11-07 <b>Last modified:</b> 2009-11-08</p> 28218<p><b>View other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index-open.html#meta.unary.prop">active issues</a> in [meta.unary.prop].</p> 28219<p><b>View all other</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html#meta.unary.prop">issues</a> in [meta.unary.prop].</p> 28220<p><b>View all issues with</b> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html#New">New</a> status.</p> 28221<p><b>Discussion:</b></p> 28222<p> 28223The specification of <tt>is_constructible<T,Args...></tt> in 28224<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2009/n3000.pdf">N3000</a> 28225uses 28226</p> 28227 28228<blockquote><pre>static_cast<T>(create<Args>()...) 28229</pre></blockquote> 28230 28231<p> 28232for the one-argument case, but <tt>static_cast</tt> also permits 28233unwanted conversions such as <tt>void*</tt> to <tt>T*</tt> and 28234<tt>Base*</tt> to <tt>Derived*</tt>. 28235</p> 28236 28237 28238<p><b>Proposed resolution:</b></p> 28239<p> 28240Change 20.6.4.3 [meta.unary.prop], p6: 28241</p> 28242 28243<blockquote> 28244<p> 28245the predicate condition for a template specialization 28246<tt>is_constructible<T, Args></tt> shall be satisfied, if and only 28247if the following <del>expression <i>CE</i></del> <ins>variable 28248definition</ins> would be well-formed: 28249</p> 28250 28251<ul> 28252<li> 28253<p> 28254if <tt>sizeof...(Args) == <ins>0</ins> <del>1</del></tt><del>, the expression</del>: 28255</p> 28256<blockquote><pre><del>static_cast<T>(create<Args>()...)</del> 28257<ins>T t;</ins> 28258</pre></blockquote> 28259</li> 28260<li> 28261<p> 28262otherwise <del>the expression</del>: 28263</p> 28264<blockquote><pre>T<ins> t</ins>(create<Args>()...); 28265</pre></blockquote> 28266</li> 28267</ul> 28268</blockquote> 28269 28270 28271 28272 28273 28274</body></html>