abi.xml revision 1.1.1.6
1<section xmlns="http://docbook.org/ns/docbook" version="5.0" 2 xml:id="appendix.porting.abi" xreflabel="abi"> 3<?dbhtml filename="abi.html"?> 4 5<info><title>ABI Policy and Guidelines</title> 6 <keywordset> 7 <keyword>C++</keyword> 8 <keyword>ABI</keyword> 9 <keyword>version</keyword> 10 <keyword>dynamic</keyword> 11 <keyword>shared</keyword> 12 <keyword>compatibility</keyword> 13 </keywordset> 14</info> 15 16 17 18<para> 19</para> 20 21<section xml:id="abi.cxx_interface"><info><title>The C++ Interface</title></info> 22 23 24<para> 25 C++ applications often depend on specific language support 26 routines, say for throwing exceptions, or catching exceptions, and 27 perhaps also depend on features in the C++ Standard Library. 28</para> 29 30<para> 31 The C++ Standard Library has many include files, types defined in 32 those include files, specific named functions, and other 33 behavior. The text of these behaviors, as written in source include 34 files, is called the Application Programing Interface, or API. 35</para> 36 37<para> 38 Furthermore, C++ source that is compiled into object files is 39 transformed by the compiler: it arranges objects with specific 40 alignment and in a particular layout, mangling names according to a 41 well-defined algorithm, has specific arrangements for the support of 42 virtual functions, etc. These details are defined as the compiler 43 Application Binary Interface, or ABI. The GNU C++ compiler uses an 44 industry-standard C++ ABI starting with version 3. Details can be 45 found in the <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://mentorembedded.github.io/cxx-abi/abi.html">ABI 46 specification</link>. 47</para> 48 49<para> 50 The GNU C++ compiler, g++, has a compiler command line option to 51 switch between various different C++ ABIs. This explicit version 52 switch is the flag <code>-fabi-version</code>. In addition, some 53 g++ command line options may change the ABI as a side-effect of 54 use. Such flags include <code>-fpack-struct</code> and 55 <code>-fno-exceptions</code>, but include others: see the complete 56 list in the GCC manual under the heading <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://gcc.gnu.org/onlinedocs/gcc/Code-Gen-Options.html#Code%20Gen%20Options">Options 57 for Code Generation Conventions</link>. 58</para> 59 60<para> 61 The configure options used when building a specific libstdc++ 62 version may also impact the resulting library ABI. The available 63 configure options, and their impact on the library ABI, are 64 documented 65<link linkend="manual.intro.setup.configure">here</link>. 66</para> 67 68<para> Putting all of these ideas together results in the C++ Standard 69Library ABI, which is the compilation of a given library API by a 70given compiler ABI. In a nutshell: 71</para> 72 73<para> 74 <quote> 75 library API + compiler ABI = library ABI 76 </quote> 77</para> 78 79<para> 80 The library ABI is mostly of interest for end-users who have 81 unresolved symbols and are linking dynamically to the C++ Standard 82 library, and who thus must be careful to compile their application 83 with a compiler that is compatible with the available C++ Standard 84 library binary. In this case, compatible is defined with the equation 85 above: given an application compiled with a given compiler ABI and 86 library API, it will work correctly with a Standard C++ Library 87 created with the same constraints. 88</para> 89 90<para> 91 To use a specific version of the C++ ABI, one must use a 92 corresponding GNU C++ toolchain (i.e., g++ and libstdc++) that 93 implements the C++ ABI in question. 94</para> 95 96</section> 97 98<section xml:id="abi.versioning"><info><title>Versioning</title></info> 99 100 101<para> The C++ interface has evolved throughout the history of the GNU 102C++ toolchain. With each release, various details have been changed so 103as to give distinct versions to the C++ interface. 104</para> 105 106 <section xml:id="abi.versioning.goals"><info><title>Goals</title></info> 107 108 109<para>Extending existing, stable ABIs. Versioning gives subsequent 110releases of library binaries the ability to add new symbols and add 111functionality, all the while retaining compatibility with the previous 112releases in the series. Thus, program binaries linked with the initial 113release of a library binary will still run correctly if the library 114binary is replaced by carefully-managed subsequent library 115binaries. This is called forward compatibility. 116</para> 117<para> 118The reverse (backwards compatibility) is not true. It is not possible 119to take program binaries linked with the latest version of a library 120binary in a release series (with additional symbols added), substitute 121in the initial release of the library binary, and remain link 122compatible. 123</para> 124 125<para>Allows multiple, incompatible ABIs to coexist at the same time. 126</para> 127 </section> 128 129 <section xml:id="abi.versioning.history"><info><title>History</title></info> 130 131 132<para> 133 How can this complexity be managed? What does C++ versioning mean? 134 Because library and compiler changes often make binaries compiled 135 with one version of the GNU tools incompatible with binaries 136 compiled with other (either newer or older) versions of the same GNU 137 tools, specific techniques are used to make managing this complexity 138 easier. 139</para> 140 141<para> 142 The following techniques are used: 143</para> 144 145 <orderedlist> 146 147 <listitem><para>Release versioning on the libgcc_s.so binary. </para> 148 149 <para>This is implemented via file names and the ELF 150 <constant>DT_SONAME</constant> mechanism (at least on ELF 151 systems). It is versioned as follows: 152 </para> 153 154 <itemizedlist> 155 <listitem><para>GCC 3.x: libgcc_s.so.1</para></listitem> 156 <listitem><para>GCC 4.x: libgcc_s.so.1</para></listitem> 157 </itemizedlist> 158 159 <para>For m68k-linux the versions differ as follows: </para> 160 161 <itemizedlist> 162 <listitem><para>GCC 3.4, GCC 4.x: libgcc_s.so.1 163 when configuring <code>--with-sjlj-exceptions</code>, or 164 libgcc_s.so.2 </para> </listitem> 165 </itemizedlist> 166 167 <para>For hppa-linux the versions differ as follows: </para> 168 169 <itemizedlist> 170 <listitem><para>GCC 3.4, GCC 4.[0-1]: either libgcc_s.so.1 171 when configuring <code>--with-sjlj-exceptions</code>, or 172 libgcc_s.so.2 </para> </listitem> 173 <listitem><para>GCC 4.[2-7]: either libgcc_s.so.3 when configuring 174 <code>--with-sjlj-exceptions</code>) or libgcc_s.so.4 175 </para> </listitem> 176 </itemizedlist> 177 178 </listitem> 179 180 <listitem><para>Symbol versioning on the libgcc_s.so binary.</para> 181 182 <para>It is versioned with the following labels and version 183 definitions, where the version definition is the maximum for a 184 particular release. Labels are cumulative. If a particular release 185 is not listed, it has the same version labels as the preceding 186 release.</para> 187 188 <para>This corresponds to the mapfile: gcc/libgcc-std.ver</para> 189 <itemizedlist> 190 <listitem><para>GCC 3.0.0: GCC_3.0</para></listitem> 191 <listitem><para>GCC 3.3.0: GCC_3.3</para></listitem> 192 <listitem><para>GCC 3.3.1: GCC_3.3.1</para></listitem> 193 <listitem><para>GCC 3.3.2: GCC_3.3.2</para></listitem> 194 <listitem><para>GCC 3.3.4: GCC_3.3.4</para></listitem> 195 <listitem><para>GCC 3.4.0: GCC_3.4</para></listitem> 196 <listitem><para>GCC 3.4.2: GCC_3.4.2</para></listitem> 197 <listitem><para>GCC 3.4.4: GCC_3.4.4</para></listitem> 198 <listitem><para>GCC 4.0.0: GCC_4.0.0</para></listitem> 199 <listitem><para>GCC 4.1.0: GCC_4.1.0</para></listitem> 200 <listitem><para>GCC 4.2.0: GCC_4.2.0</para></listitem> 201 <listitem><para>GCC 4.3.0: GCC_4.3.0</para></listitem> 202 <listitem><para>GCC 4.4.0: GCC_4.4.0</para></listitem> 203 <listitem><para>GCC 4.5.0: GCC_4.5.0</para></listitem> 204 <listitem><para>GCC 4.6.0: GCC_4.6.0</para></listitem> 205 <listitem><para>GCC 4.7.0: GCC_4.7.0</para></listitem> 206 <listitem><para>GCC 4.8.0: GCC_4.8.0</para></listitem> 207 </itemizedlist> 208 </listitem> 209 210 <listitem> 211 <para> 212 Release versioning on the libstdc++.so binary, implemented in 213 the same way as the libgcc_s.so binary above. Listed is the 214 filename: <constant>DT_SONAME</constant> can be deduced from 215 the filename by removing the last two period-delimited numbers. For 216 example, filename <filename>libstdc++.so.5.0.4</filename> 217 corresponds to a <constant>DT_SONAME</constant> of 218 <constant>libstdc++.so.5</constant>. Binaries with equivalent 219 <constant>DT_SONAME</constant>s are forward-compatibile: in 220 the table below, releases incompatible with the previous 221 one are explicitly noted. 222 If a particular release is not listed, its libstdc++.so binary 223 has the same filename and <constant>DT_SONAME</constant> as the 224 preceding release. 225 </para> 226 227 <para>It is versioned as follows: 228 </para> 229 <itemizedlist> 230 <listitem><para>GCC 3.0.0: libstdc++.so.3.0.0</para></listitem> 231 <listitem><para>GCC 3.0.1: libstdc++.so.3.0.1</para></listitem> 232 <listitem><para>GCC 3.0.2: libstdc++.so.3.0.2</para></listitem> 233 <listitem><para>GCC 3.0.3: libstdc++.so.3.0.2 (See Note 1)</para></listitem> 234 <listitem><para>GCC 3.0.4: libstdc++.so.3.0.4</para></listitem> 235 <listitem><para>GCC 3.1.0: libstdc++.so.4.0.0 <emphasis>(Incompatible with previous)</emphasis></para></listitem> 236 <listitem><para>GCC 3.1.1: libstdc++.so.4.0.1</para></listitem> 237 <listitem><para>GCC 3.2.0: libstdc++.so.5.0.0 <emphasis>(Incompatible with previous)</emphasis></para></listitem> 238 <listitem><para>GCC 3.2.1: libstdc++.so.5.0.1</para></listitem> 239 <listitem><para>GCC 3.2.2: libstdc++.so.5.0.2</para></listitem> 240 <listitem><para>GCC 3.2.3: libstdc++.so.5.0.3 (See Note 2)</para></listitem> 241 <listitem><para>GCC 3.3.0: libstdc++.so.5.0.4</para></listitem> 242 <listitem><para>GCC 3.3.1: libstdc++.so.5.0.5</para></listitem> 243 <listitem><para>GCC 3.4.0: libstdc++.so.6.0.0 <emphasis>(Incompatible with previous)</emphasis></para></listitem> 244 <listitem><para>GCC 3.4.1: libstdc++.so.6.0.1</para></listitem> 245 <listitem><para>GCC 3.4.2: libstdc++.so.6.0.2</para></listitem> 246 <listitem><para>GCC 3.4.3: libstdc++.so.6.0.3</para></listitem> 247 <listitem><para>GCC 4.0.0: libstdc++.so.6.0.4</para></listitem> 248 <listitem><para>GCC 4.0.1: libstdc++.so.6.0.5</para></listitem> 249 <listitem><para>GCC 4.0.2: libstdc++.so.6.0.6</para></listitem> 250 <listitem><para>GCC 4.0.3: libstdc++.so.6.0.7</para></listitem> 251 <listitem><para>GCC 4.1.0: libstdc++.so.6.0.7</para></listitem> 252 <listitem><para>GCC 4.1.1: libstdc++.so.6.0.8</para></listitem> 253 <listitem><para>GCC 4.2.0: libstdc++.so.6.0.9</para></listitem> 254 <listitem><para>GCC 4.2.1: libstdc++.so.6.0.9 (See Note 3)</para></listitem> 255 <listitem><para>GCC 4.2.2: libstdc++.so.6.0.9</para></listitem> 256 <listitem><para>GCC 4.3.0: libstdc++.so.6.0.10</para></listitem> 257 <listitem><para>GCC 4.4.0: libstdc++.so.6.0.11</para></listitem> 258 <listitem><para>GCC 4.4.1: libstdc++.so.6.0.12</para></listitem> 259 <listitem><para>GCC 4.4.2: libstdc++.so.6.0.13</para></listitem> 260 <listitem><para>GCC 4.5.0: libstdc++.so.6.0.14</para></listitem> 261 <listitem><para>GCC 4.6.0: libstdc++.so.6.0.15</para></listitem> 262 <listitem><para>GCC 4.6.1: libstdc++.so.6.0.16</para></listitem> 263 <listitem><para>GCC 4.7.0: libstdc++.so.6.0.17</para></listitem> 264 <listitem><para>GCC 4.8.0: libstdc++.so.6.0.18</para></listitem> 265 <listitem><para>GCC 4.8.3: libstdc++.so.6.0.19</para></listitem> 266 <listitem><para>GCC 4.9.0: libstdc++.so.6.0.20</para></listitem> 267 <listitem><para>GCC 5.1.0: libstdc++.so.6.0.21</para></listitem> 268 <listitem><para>GCC 6.1.0: libstdc++.so.6.0.22</para></listitem> 269 </itemizedlist> 270 <para> 271 Note 1: Error should be libstdc++.so.3.0.3. 272 </para> 273 <para> 274 Note 2: Not strictly required. 275 </para> 276 <para> 277 Note 3: This release (but not previous or subsequent) has one 278 known incompatibility, see <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33678">33678</link> 279 in the GCC bug database. 280 </para> 281 </listitem> 282 283 <listitem><para>Symbol versioning on the libstdc++.so binary.</para> 284 285 <para>mapfile: libstdc++-v3/config/abi/pre/gnu.ver</para> 286 <para>It is versioned with the following labels and version 287 definitions, where the version definition is the maximum for a 288 particular release. Note, only symbols which are newly introduced 289 will use the maximum version definition. Thus, for release series 290 with the same label, but incremented version definitions, the later 291 release has both versions. (An example of this would be the 292 GCC 3.2.1 release, which has GLIBCPP_3.2.1 for new symbols and 293 GLIBCPP_3.2 for symbols that were introduced in the GCC 3.2.0 294 release.) If a particular release is not listed, it has the same 295 version labels as the preceding release. 296 </para> 297 <itemizedlist> 298 <listitem><para>GCC 3.0.0: (Error, not versioned)</para></listitem> 299 <listitem><para>GCC 3.0.1: (Error, not versioned)</para></listitem> 300 <listitem><para>GCC 3.0.2: (Error, not versioned)</para></listitem> 301 <listitem><para>GCC 3.0.3: (Error, not versioned)</para></listitem> 302 <listitem><para>GCC 3.0.4: (Error, not versioned)</para></listitem> 303 <listitem><para>GCC 3.1.0: GLIBCPP_3.1, CXXABI_1</para></listitem> 304 <listitem><para>GCC 3.1.1: GLIBCPP_3.1, CXXABI_1</para></listitem> 305 <listitem><para>GCC 3.2.0: GLIBCPP_3.2, CXXABI_1.2</para></listitem> 306 <listitem><para>GCC 3.2.1: GLIBCPP_3.2.1, CXXABI_1.2</para></listitem> 307 <listitem><para>GCC 3.2.2: GLIBCPP_3.2.2, CXXABI_1.2</para></listitem> 308 <listitem><para>GCC 3.2.3: GLIBCPP_3.2.2, CXXABI_1.2</para></listitem> 309 <listitem><para>GCC 3.3.0: GLIBCPP_3.2.2, CXXABI_1.2.1</para></listitem> 310 <listitem><para>GCC 3.3.1: GLIBCPP_3.2.3, CXXABI_1.2.1</para></listitem> 311 <listitem><para>GCC 3.3.2: GLIBCPP_3.2.3, CXXABI_1.2.1</para></listitem> 312 <listitem><para>GCC 3.3.3: GLIBCPP_3.2.3, CXXABI_1.2.1</para></listitem> 313 <listitem><para>GCC 3.4.0: GLIBCXX_3.4, CXXABI_1.3</para></listitem> 314 <listitem><para>GCC 3.4.1: GLIBCXX_3.4.1, CXXABI_1.3</para></listitem> 315 <listitem><para>GCC 3.4.2: GLIBCXX_3.4.2</para></listitem> 316 <listitem><para>GCC 3.4.3: GLIBCXX_3.4.3</para></listitem> 317 <listitem><para>GCC 4.0.0: GLIBCXX_3.4.4, CXXABI_1.3.1</para></listitem> 318 <listitem><para>GCC 4.0.1: GLIBCXX_3.4.5</para></listitem> 319 <listitem><para>GCC 4.0.2: GLIBCXX_3.4.6</para></listitem> 320 <listitem><para>GCC 4.0.3: GLIBCXX_3.4.7</para></listitem> 321 <listitem><para>GCC 4.1.1: GLIBCXX_3.4.8</para></listitem> 322 <listitem><para>GCC 4.2.0: GLIBCXX_3.4.9</para></listitem> 323 <listitem><para>GCC 4.3.0: GLIBCXX_3.4.10, CXXABI_1.3.2</para></listitem> 324 <listitem><para>GCC 4.4.0: GLIBCXX_3.4.11, CXXABI_1.3.3</para></listitem> 325 <listitem><para>GCC 4.4.1: GLIBCXX_3.4.12, CXXABI_1.3.3</para></listitem> 326 <listitem><para>GCC 4.4.2: GLIBCXX_3.4.13, CXXABI_1.3.3</para></listitem> 327 <listitem><para>GCC 4.5.0: GLIBCXX_3.4.14, CXXABI_1.3.4</para></listitem> 328 <listitem><para>GCC 4.6.0: GLIBCXX_3.4.15, CXXABI_1.3.5</para></listitem> 329 <listitem><para>GCC 4.6.1: GLIBCXX_3.4.16, CXXABI_1.3.5</para></listitem> 330 <listitem><para>GCC 4.7.0: GLIBCXX_3.4.17, CXXABI_1.3.6</para></listitem> 331 <listitem><para>GCC 4.8.0: GLIBCXX_3.4.18, CXXABI_1.3.7</para></listitem> 332 <listitem><para>GCC 4.8.3: GLIBCXX_3.4.19, CXXABI_1.3.7</para></listitem> 333 <listitem><para>GCC 4.9.0: GLIBCXX_3.4.20, CXXABI_1.3.8</para></listitem> 334 <listitem><para>GCC 5.1.0: GLIBCXX_3.4.21, CXXABI_1.3.9</para></listitem> 335 <listitem><para>GCC 6.1.0: GLIBCXX_3.4.22, CXXABI_1.3.10</para></listitem> 336 </itemizedlist> 337 </listitem> 338 339 <listitem> 340 <para>Incremental bumping of a compiler pre-defined macro, 341 __GXX_ABI_VERSION. This macro is defined as the version of the 342 compiler v3 ABI, with g++ 3.0 being version 100. This macro will 343 be automatically defined whenever g++ is used (the curious can 344 test this by invoking g++ with the '-v' flag.) 345 </para> 346 347 <para> 348 This macro was defined in the file "lang-specs.h" in the gcc/cp directory. 349 Later versions defined it in "c-common.c" in the gcc directory, and from 350 G++ 3.4 it is defined in c-cppbuiltin.c and its value determined by the 351 '-fabi-version' command line option. 352 </para> 353 354 <para> 355 It is versioned as follows, where 'n' is given by '-fabi-version=n': 356 </para> 357 <itemizedlist> 358 <listitem><para>GCC 3.0: 100</para></listitem> 359 <listitem><para>GCC 3.1: 100 (Error, should be 101)</para></listitem> 360 <listitem><para>GCC 3.2: 102</para></listitem> 361 <listitem><para>GCC 3.3: 102</para></listitem> 362 <listitem><para>GCC 3.4, GCC 4.x: 102 (when n=1)</para></listitem> 363 <listitem><para>GCC 3.4, GCC 4.x: 1000 + n (when n>1) </para></listitem> 364 <listitem><para>GCC 3.4, GCC 4.x: 999999 (when n=0)</para></listitem> 365 </itemizedlist> 366 <para/> 367 </listitem> 368 369 <listitem> 370 <para>Changes to the default compiler option for 371 <code>-fabi-version</code>. 372 </para> 373 <para> 374 It is versioned as follows: 375 </para> 376 <itemizedlist> 377 <listitem><para>GCC 3.0: (Error, not versioned) </para></listitem> 378 <listitem><para>GCC 3.1: (Error, not versioned) </para></listitem> 379 <listitem><para>GCC 3.2: <code>-fabi-version=1</code></para></listitem> 380 <listitem><para>GCC 3.3: <code>-fabi-version=1</code></para></listitem> 381 <listitem><para>GCC 3.4, GCC 4.x: <code>-fabi-version=2</code> <emphasis>(Incompatible with previous)</emphasis></para></listitem> 382 </itemizedlist> 383 <para/> 384 </listitem> 385 386 <listitem> 387 <para>Incremental bumping of a library pre-defined macro. For releases 388 before 3.4.0, the macro is __GLIBCPP__. For later releases, it's 389 __GLIBCXX__. (The libstdc++ project generously changed from CPP to 390 CXX throughout its source to allow the "C" pre-processor the CPP 391 macro namespace.) These macros are defined as the date the library 392 was released, in compressed ISO date format, as an unsigned long. 393 </para> 394 395 <para> 396 This macro is defined in the file "c++config" in the 397 "libstdc++-v3/include/bits" directory. Up to GCC 4.1.0, it was 398 changed every night by an automated script. Since GCC 4.1.0 it is set 399 during configuration to the same value as 400 <filename>gcc/DATESTAMP</filename>, so for an official release its value 401 is the same as the date of the release, which is given in the <link 402 xmlns:xlink="http://www.w3.org/1999/xlink" 403 xlink:href="https://gcc.gnu.org/develop.html#timeline">GCC Release 404 Timeline</link>. 405 </para> 406 407 <para> 408 This macro is not useful for determining whether a particular feature is 409 supported by the version of libstdc++ you are using. The date of a release 410 might be after a feature was added to the development trunk, but the 411 release could be from an older branch. For example, in the 5.4.0 release 412 the macro has the value 20160603 which is greater than the 20160427 value 413 of the macro in the 6.1.0 release, but there are features supported in the 414 6.1.0 release that are not supported in 5.4.0 release. 415 You also can't test for the exact values listed below to try and 416 identify a release, because a snapshot taken from the gcc-5-branch on 417 2016-04-27 would have the same value for the macro as the 6.1.0 release 418 despite being a different version. 419 Many GNU/Linux distributions build their GCC packages from snapshots, so 420 the macro can have dates that doesn't correspond to official releases. 421 </para> 422 423 <para> 424 It is versioned as follows: 425 </para> 426 <itemizedlist> 427 <listitem><para>GCC 3.0.0: 20010615</para></listitem> 428 <listitem><para>GCC 3.0.1: 20010819</para></listitem> 429 <listitem><para>GCC 3.0.2: 20011023</para></listitem> 430 <listitem><para>GCC 3.0.3: 20011220</para></listitem> 431 <listitem><para>GCC 3.0.4: 20020220</para></listitem> 432 <listitem><para>GCC 3.1.0: 20020514</para></listitem> 433 <listitem><para>GCC 3.1.1: 20020725</para></listitem> 434 <listitem><para>GCC 3.2.0: 20020814</para></listitem> 435 <listitem><para>GCC 3.2.1: 20021119</para></listitem> 436 <listitem><para>GCC 3.2.2: 20030205</para></listitem> 437 <listitem><para>GCC 3.2.3: 20030422</para></listitem> 438 <listitem><para>GCC 3.3.0: 20030513</para></listitem> 439 <listitem><para>GCC 3.3.1: 20030804</para></listitem> 440 <listitem><para>GCC 3.3.2: 20031016</para></listitem> 441 <listitem><para>GCC 3.3.3: 20040214</para></listitem> 442 <listitem><para>GCC 3.4.0: 20040419</para></listitem> 443 <listitem><para>GCC 3.4.1: 20040701</para></listitem> 444 <listitem><para>GCC 3.4.2: 20040906</para></listitem> 445 <listitem><para>GCC 3.4.3: 20041105</para></listitem> 446 <listitem><para>GCC 3.4.4: 20050519</para></listitem> 447 <listitem><para>GCC 3.4.5: 20051201</para></listitem> 448 <listitem><para>GCC 3.4.6: 20060306</para></listitem> 449 <listitem><para>GCC 4.0.0: 20050421</para></listitem> 450 <listitem><para>GCC 4.0.1: 20050707</para></listitem> 451 <listitem><para>GCC 4.0.2: 20050921</para></listitem> 452 <listitem><para>GCC 4.0.3: 20060309</para></listitem> 453 <listitem><para> 454 GCC 4.1.0 and later: the GCC release date, as shown in the 455 <link xmlns:xlink="http://www.w3.org/1999/xlink" 456 xlink:href="https://gcc.gnu.org/develop.html#timeline">GCC 457 Release Timeline</link> 458 </para></listitem> 459 </itemizedlist> 460 <para/> 461 </listitem> 462 463 <listitem> 464 <para> 465 Incremental bumping of a library pre-defined macro, 466 _GLIBCPP_VERSION. This macro is defined as the released version of 467 the library, as a string literal. This is only implemented in 468 GCC 3.1.0 releases and higher, and is deprecated in 3.4 (where it 469 is called _GLIBCXX_VERSION). 470 </para> 471 472 <para> 473 This macro is defined in the file "c++config" in the 474 "libstdc++-v3/include/bits" directory and is generated 475 automatically by autoconf as part of the configure-time generation 476 of config.h. 477 </para> 478 479 <para> 480 It is versioned as follows: 481 </para> 482 <itemizedlist> 483 <listitem><para>GCC 3.0.0: "3.0.0"</para></listitem> 484 <listitem><para>GCC 3.0.1: "3.0.0" (Error, should be "3.0.1")</para></listitem> 485 <listitem><para>GCC 3.0.2: "3.0.0" (Error, should be "3.0.2")</para></listitem> 486 <listitem><para>GCC 3.0.3: "3.0.0" (Error, should be "3.0.3")</para></listitem> 487 <listitem><para>GCC 3.0.4: "3.0.0" (Error, should be "3.0.4")</para></listitem> 488 <listitem><para>GCC 3.1.0: "3.1.0"</para></listitem> 489 <listitem><para>GCC 3.1.1: "3.1.1"</para></listitem> 490 <listitem><para>GCC 3.2.0: "3.2"</para></listitem> 491 <listitem><para>GCC 3.2.1: "3.2.1"</para></listitem> 492 <listitem><para>GCC 3.2.2: "3.2.2"</para></listitem> 493 <listitem><para>GCC 3.2.3: "3.2.3"</para></listitem> 494 <listitem><para>GCC 3.3.0: "3.3"</para></listitem> 495 <listitem><para>GCC 3.3.1: "3.3.1"</para></listitem> 496 <listitem><para>GCC 3.3.2: "3.3.2"</para></listitem> 497 <listitem><para>GCC 3.3.3: "3.3.3"</para></listitem> 498 <listitem><para>GCC 3.4: "version-unused"</para></listitem> 499 <listitem><para>GCC 4.x: "version-unused"</para></listitem> 500 </itemizedlist> 501 <para/> 502 </listitem> 503 504 <listitem> 505 <para> 506 Matching each specific C++ compiler release to a specific set of 507 C++ include files. This is only implemented in GCC 3.1.1 releases 508 and higher. 509 </para> 510 <para> 511 All C++ includes are installed in 512 <filename class="directory">include/c++</filename>, then nest in a 513 directory hierarchy corresponding to the C++ compiler's released 514 version. This version corresponds to the variable "gcc_version" in 515 "libstdc++-v3/acinclude.m4," and more details can be found in that 516 file's macro GLIBCXX_CONFIGURE (GLIBCPP_CONFIGURE before GCC 3.4.0). 517 </para> 518 <para> 519 C++ includes are versioned as follows: 520 </para> 521 <itemizedlist> 522 <listitem><para>GCC 3.0.0: include/g++-v3</para></listitem> 523 <listitem><para>GCC 3.0.1: include/g++-v3</para></listitem> 524 <listitem><para>GCC 3.0.2: include/g++-v3</para></listitem> 525 <listitem><para>GCC 3.0.3: include/g++-v3</para></listitem> 526 <listitem><para>GCC 3.0.4: include/g++-v3</para></listitem> 527 <listitem><para>GCC 3.1.0: include/g++-v3</para></listitem> 528 <listitem><para>GCC 3.1.1: include/c++/3.1.1</para></listitem> 529 <listitem><para>GCC 3.2.0: include/c++/3.2</para></listitem> 530 <listitem><para>GCC 3.2.1: include/c++/3.2.1</para></listitem> 531 <listitem><para>GCC 3.2.2: include/c++/3.2.2</para></listitem> 532 <listitem><para>GCC 3.2.3: include/c++/3.2.3</para></listitem> 533 <listitem><para>GCC 3.3.0: include/c++/3.3</para></listitem> 534 <listitem><para>GCC 3.3.1: include/c++/3.3.1</para></listitem> 535 <listitem><para>GCC 3.3.2: include/c++/3.3.2</para></listitem> 536 <listitem><para>GCC 3.3.3: include/c++/3.3.3</para></listitem> 537 <listitem><para>GCC 3.4.x: include/c++/3.4.x</para></listitem> 538 <listitem><para>GCC 4.x.y: include/c++/4.x.y</para></listitem> 539 <listitem><para>GCC 5.x.0: include/c++/5.x.0</para></listitem> 540 </itemizedlist> 541 <para/> 542 </listitem> 543 </orderedlist> 544 545<para> 546 Taken together, these techniques can accurately specify interface 547 and implementation changes in the GNU C++ tools themselves. Used 548 properly, they allow both the GNU C++ tools implementation, and 549 programs using them, an evolving yet controlled development that 550 maintains backward compatibility. 551</para> 552 553 554 </section> 555 556 <section xml:id="abi.versioning.prereq"><info><title>Prerequisites</title></info> 557 558 <para> 559 Minimum environment that supports a versioned ABI: A supported 560 dynamic linker, a GNU linker of sufficient vintage to understand 561 demangled C++ name globbing (ld) or the Sun linker, a shared 562 executable compiled 563 with g++, and shared libraries (libgcc_s, libstdc++) compiled by 564 a compiler (g++) with a compatible ABI. Phew. 565 </para> 566 567 <para> 568 On top of all that, an additional constraint: libstdc++ did not 569 attempt to version symbols (or age gracefully, really) until 570 version 3.1.0. 571 </para> 572 573 <para> 574 Most modern GNU/Linux and BSD versions, particularly ones using 575 GCC 3.1 and later, will meet the 576 requirements above, as does Solaris 2.5 and up. 577 </para> 578 </section> 579 580 <section xml:id="abi.versioning.config"><info><title>Configuring</title></info> 581 582 583 <para> 584 It turns out that most of the configure options that change 585 default behavior will impact the mangled names of exported 586 symbols, and thus impact versioning and compatibility. 587 </para> 588 589 <para> 590 For more information on configure options, including ABI 591 impacts, see: 592 <link linkend="manual.intro.setup.configure">here</link> 593 </para> 594 595 <para> 596 There is one flag that explicitly deals with symbol versioning: 597 --enable-symvers. 598 </para> 599 600 <para> 601 In particular, libstdc++-v3/acinclude.m4 has a macro called 602 GLIBCXX_ENABLE_SYMVERS that defaults to yes (or the argument 603 passed in via --enable-symvers=foo). At that point, the macro 604 attempts to make sure that all the requirement for symbol 605 versioning are in place. For more information, please consult 606 acinclude.m4. 607 </para> 608 </section> 609 610 <section xml:id="abi.versioning.active"><info><title>Checking Active</title></info> 611 612 613 <para> 614 When the GNU C++ library is being built with symbol versioning 615 on, you should see the following at configure time for 616 libstdc++ (showing either 'gnu' or another of the supported styles): 617 </para> 618 619<screen> 620<computeroutput> 621 checking versioning on shared library symbols... gnu 622</computeroutput> 623</screen> 624 625<para> 626 If you don't see this line in the configure output, or if this line 627 appears but the last word is 'no', then you are out of luck. 628</para> 629 630<para> 631 If the compiler is pre-installed, a quick way to test is to compile 632 the following (or any) simple C++ file and link it to the shared 633 libstdc++ library: 634</para> 635 636<programlisting> 637#include <iostream> 638 639int main() 640{ std::cout << "hello" << std::endl; return 0; } 641 642%g++ hello.cc -o hello.out 643 644%ldd hello.out 645 libstdc++.so.5 => /usr/lib/libstdc++.so.5 (0x00764000) 646 libm.so.6 => /lib/tls/libm.so.6 (0x004a8000) 647 libgcc_s.so.1 => /mnt/hd/bld/gcc/gcc/libgcc_s.so.1 (0x40016000) 648 libc.so.6 => /lib/tls/libc.so.6 (0x0036d000) 649 /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x00355000) 650 651%nm hello.out 652</programlisting> 653 654<para> 655If you see symbols in the resulting output with "GLIBCXX_3" as part 656of the name, then the executable is versioned. Here's an example: 657</para> 658 659<para> 660 <code>U _ZNSt8ios_base4InitC1Ev@@GLIBCXX_3.4</code> 661</para> 662 663<para> 664On Solaris 2, you can use <code>pvs -r</code> instead: 665</para> 666 667<programlisting> 668%g++ hello.cc -o hello.out 669 670%pvs -r hello.out 671 libstdc++.so.6 (GLIBCXX_3.4, GLIBCXX_3.4.12); 672 libgcc_s.so.1 (GCC_3.0); 673 libc.so.1 (SUNWprivate_1.1, SYSVABI_1.3); 674</programlisting> 675 676<para> 677<code>ldd -v</code> works too, but is very verbose. 678</para> 679 680 </section> 681</section> 682 683<section xml:id="abi.changes_allowed"><info><title>Allowed Changes</title></info> 684 685 686<para> 687The following will cause the library minor version number to 688increase, say from "libstdc++.so.3.0.4" to "libstdc++.so.3.0.5". 689</para> 690<orderedlist> 691 <listitem><para>Adding an exported global or static data member</para></listitem> 692 <listitem><para>Adding an exported function, static or non-virtual member function</para></listitem> 693 <listitem><para>Adding an exported symbol or symbols by additional instantiations</para></listitem> 694</orderedlist> 695<para> 696Other allowed changes are possible. 697</para> 698 699</section> 700 701<section xml:id="abi.changes_no"><info><title>Prohibited Changes</title></info> 702 703 704<para> 705The following non-exhaustive list will cause the library major version 706number to increase, say from "libstdc++.so.3.0.4" to 707"libstdc++.so.4.0.0". 708</para> 709 710<orderedlist> 711 <listitem><para>Changes in the gcc/g++ compiler ABI</para></listitem> 712<listitem><para>Changing size of an exported symbol</para></listitem> 713<listitem><para>Changing alignment of an exported symbol</para></listitem> 714<listitem><para>Changing the layout of an exported symbol</para></listitem> 715<listitem><para>Changing mangling on an exported symbol</para></listitem> 716<listitem><para>Deleting an exported symbol</para></listitem> 717<listitem><para>Changing the inheritance properties of a type by adding or removing 718 base classes</para></listitem> 719<listitem><para> 720 Changing the size, alignment, or layout of types 721 specified in the C++ standard. These may not necessarily be 722 instantiated or otherwise exported in the library binary, and 723 include all the required locale facets, as well as things like 724 std::basic_streambuf, et al. 725</para></listitem> 726 727<listitem><para> Adding an explicit copy constructor or destructor to a 728class that would otherwise have implicit versions. This will change 729the way the compiler deals with this class in by-value return 730statements or parameters: instead of passing instances of this 731class in registers, the compiler will be forced to use memory. See the 732section on <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://mentorembedded.github.io/cxx-abi/abi.html#calls">Function 733Calling Conventions and APIs</link> 734 of the C++ ABI documentation for further details. 735</para></listitem> 736 737</orderedlist> 738 739</section> 740 741 742 743<section xml:id="abi.impl"><info><title>Implementation</title></info> 744 745 746<orderedlist> 747 <listitem> 748 <para> 749 Separation of interface and implementation 750 </para> 751 <para> 752 This is accomplished by two techniques that separate the API from 753 the ABI: forcing undefined references to link against a library 754 binary for definitions. 755 </para> 756 757<variablelist> 758 <varlistentry> 759 <term>Include files have declarations, source files have defines</term> 760 761 <listitem> 762 <para> 763 For non-templatized types, such as much of <code>class 764 locale</code>, the appropriate standard C++ include, say 765 <code>locale</code>, can contain full declarations, while 766 various source files (say <code> locale.cc, locale_init.cc, 767 localename.cc</code>) contain definitions. 768 </para> 769 </listitem> 770 </varlistentry> 771 772 <varlistentry> 773 <term>Extern template on required types</term> 774 775 <listitem> 776 <para> 777 For parts of the standard that have an explicit list of 778 required instantiations, the GNU extension syntax <code> extern 779 template </code> can be used to control where template 780 definitions reside. By marking required instantiations as 781 <code> extern template </code> in include files, and providing 782 explicit instantiations in the appropriate instantiation files, 783 non-inlined template functions can be versioned. This technique 784 is mostly used on parts of the standard that require <code> 785 char</code> and <code> wchar_t</code> instantiations, and 786 includes <code> basic_string</code>, the locale facets, and the 787 types in <code> iostreams</code>. 788 </para> 789 </listitem> 790 </varlistentry> 791 792 </variablelist> 793 794 <para> 795 In addition, these techniques have the additional benefit that they 796 reduce binary size, which can increase runtime performance. 797 </para> 798 </listitem> 799 800 <listitem> 801 <para> 802 Namespaces linking symbol definitions to export mapfiles 803 </para> 804 <para> 805 All symbols in the shared library binary are processed by a 806 linker script at build time that either allows or disallows 807 external linkage. Because of this, some symbols, regardless of 808 normal C/C++ linkage, are not visible. Symbols that are internal 809 have several appealing characteristics: by not exporting the 810 symbols, there are no relocations when the shared library is 811 started and thus this makes for faster runtime loading 812 performance by the underlying dynamic loading mechanism. In 813 addition, they have the possibility of changing without impacting 814 ABI compatibility. 815 </para> 816 817<para>The following namespaces are transformed by the mapfile:</para> 818 819<variablelist> 820 821 <varlistentry> 822<term><code>namespace std</code></term> 823<listitem><para> Defaults to exporting all symbols in label 824<code>GLIBCXX</code> that do not begin with an underscore, i.e., 825<code>__test_func</code> would not be exported by default. Select 826exceptional symbols are allowed to be visible.</para></listitem> 827 </varlistentry> 828 829 <varlistentry> 830<term><code>namespace __gnu_cxx</code></term> 831<listitem><para> Defaults to not exporting any symbols in label 832<code>GLIBCXX</code>, select items are allowed to be visible.</para></listitem> 833 </varlistentry> 834 835 <varlistentry> 836<term><code>namespace __gnu_internal</code></term> 837<listitem><para> Defaults to not exported, no items are allowed to be visible.</para></listitem> 838 </varlistentry> 839 840 <varlistentry> 841<term><code>namespace __cxxabiv1</code>, aliased to <code> namespace abi</code></term> 842<listitem><para> Defaults to not exporting any symbols in label 843<code>CXXABI</code>, select items are allowed to be visible.</para></listitem> 844 </varlistentry> 845 846</variablelist> 847<para> 848</para> 849</listitem> 850 851 <listitem><para>Freezing the API</para> 852 <para>Disallowed changes, as above, are not made on a stable release 853branch. Enforcement tends to be less strict with GNU extensions that 854standard includes.</para> 855</listitem> 856</orderedlist> 857 858</section> 859 860<section xml:id="abi.testing"><info><title>Testing</title></info> 861 862 863 <section xml:id="abi.testing.single"><info><title>Single ABI Testing</title></info> 864 865 866 <para> 867 Testing for GNU C++ ABI changes is composed of two distinct 868 areas: testing the C++ compiler (g++) for compiler changes, and 869 testing the C++ library (libstdc++) for library changes. 870 </para> 871 872 <para> 873 Testing the C++ compiler ABI can be done various ways. 874 </para> 875 876 <para> 877 One. Intel ABI checker. 878 </para> 879 880<para> 881Two. 882The second is yet unreleased, but has been announced on the gcc 883mailing list. It is yet unspecified if these tools will be freely 884available, and able to be included in a GNU project. Please contact 885Mark Mitchell (mark@codesourcery.com) for more details, and current 886status. 887</para> 888 889<para> 890Three. 891Involves using the vlad.consistency test framework. This has also been 892discussed on the gcc mailing lists. 893</para> 894 895<para> 896Testing the C++ library ABI can also be done various ways. 897</para> 898 899<para> 900One. 901(Brendan Kehoe, Jeff Law suggestion to run 'make check-c++' two ways, 902one with a new compiler and an old library, and the other with an old 903compiler and a new library, and look for testsuite regressions) 904</para> 905 906<para> 907Details on how to set this kind of test up can be found here: 908http://gcc.gnu.org/ml/gcc/2002-08/msg00142.html 909</para> 910 911<para> 912Two. 913Use the 'make check-abi' rule in the libstdc++ Makefile. 914</para> 915 916<para> 917This is a proactive check of the library ABI. Currently, exported symbol 918names that are either weak or defined are checked against a last known 919good baseline. Currently, this baseline is keyed off of 3.4.0 920binaries, as this was the last time the .so number was incremented. In 921addition, all exported names are demangled, and the exported objects 922are checked to make sure they are the same size as the same object in 923the baseline. 924 925Notice that each baseline is relative to a <emphasis>default</emphasis> 926configured library and compiler: in particular, if options such as 927--enable-clocale, or --with-cpu, in case of multilibs, are used at 928configure time, the check may fail, either because of substantive 929differences or because of limitations of the current checking 930machinery. 931</para> 932 933<para> 934This dataset is insufficient, yet a start. Also needed is a 935comprehensive check for all user-visible types part of the standard 936library for sizeof() and alignof() changes. 937</para> 938 939<para> 940Verifying compatible layouts of objects is not even attempted. It 941should be possible to use sizeof, alignof, and offsetof to compute 942offsets for each structure and type in the standard library, saving to 943another datafile. Then, compute this in a similar way for new 944binaries, and look for differences. 945</para> 946 947<para> 948Another approach might be to use the -fdump-class-hierarchy flag to 949get information. However, currently this approach gives insufficient 950data for use in library testing, as class data members, their offsets, 951and other detailed data is not displayed with this flag. 952(See PR g++/7470 on how this was used to find bugs.) 953</para> 954 955<para> 956Perhaps there are other C++ ABI checkers. If so, please notify 957us. We'd like to know about them! 958</para> 959 960 </section> 961 <section xml:id="abi.testing.multi"><info><title>Multiple ABI Testing</title></info> 962 963<para> 964A "C" application, dynamically linked to two shared libraries, liba, 965libb. The dependent library liba is a C++ shared library compiled with 966GCC 3.3, and uses io, exceptions, locale, etc. The dependent library 967libb is a C++ shared library compiled with GCC 3.4, and also uses io, 968exceptions, locale, etc. 969</para> 970 971<para> As above, libone is constructed as follows: </para> 972<programlisting> 973%$bld/H-x86-gcc-3.4.0/bin/g++ -fPIC -DPIC -c a.cc 974 975%$bld/H-x86-gcc-3.4.0/bin/g++ -shared -Wl,-soname -Wl,libone.so.1 -Wl,-O1 -Wl,-z,defs a.o -o libone.so.1.0.0 976 977%ln -s libone.so.1.0.0 libone.so 978 979%$bld/H-x86-gcc-3.4.0/bin/g++ -c a.cc 980 981%ar cru libone.a a.o 982</programlisting> 983 984<para> And, libtwo is constructed as follows: </para> 985 986<programlisting> 987%$bld/H-x86-gcc-3.3.3/bin/g++ -fPIC -DPIC -c b.cc 988 989%$bld/H-x86-gcc-3.3.3/bin/g++ -shared -Wl,-soname -Wl,libtwo.so.1 -Wl,-O1 -Wl,-z,defs b.o -o libtwo.so.1.0.0 990 991%ln -s libtwo.so.1.0.0 libtwo.so 992 993%$bld/H-x86-gcc-3.3.3/bin/g++ -c b.cc 994 995%ar cru libtwo.a b.o 996</programlisting> 997 998<para> ...with the resulting libraries looking like </para> 999 1000<screen> 1001<computeroutput> 1002%ldd libone.so.1.0.0 1003 libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x40016000) 1004 libm.so.6 => /lib/tls/libm.so.6 (0x400fa000) 1005 libgcc_s.so.1 => /mnt/hd/bld/gcc/gcc/libgcc_s.so.1 (0x4011c000) 1006 libc.so.6 => /lib/tls/libc.so.6 (0x40125000) 1007 /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x00355000) 1008 1009%ldd libtwo.so.1.0.0 1010 libstdc++.so.5 => /usr/lib/libstdc++.so.5 (0x40027000) 1011 libm.so.6 => /lib/tls/libm.so.6 (0x400e1000) 1012 libgcc_s.so.1 => /mnt/hd/bld/gcc/gcc/libgcc_s.so.1 (0x40103000) 1013 libc.so.6 => /lib/tls/libc.so.6 (0x4010c000) 1014 /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x00355000) 1015</computeroutput> 1016</screen> 1017 1018<para> 1019 Then, the "C" compiler is used to compile a source file that uses 1020 functions from each library. 1021</para> 1022<programlisting> 1023gcc test.c -g -O2 -L. -lone -ltwo /usr/lib/libstdc++.so.5 /usr/lib/libstdc++.so.6 1024</programlisting> 1025 1026<para> 1027 Which gives the expected: 1028</para> 1029 1030<screen> 1031<computeroutput> 1032%ldd a.out 1033 libstdc++.so.5 => /usr/lib/libstdc++.so.5 (0x00764000) 1034 libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x40015000) 1035 libc.so.6 => /lib/tls/libc.so.6 (0x0036d000) 1036 libm.so.6 => /lib/tls/libm.so.6 (0x004a8000) 1037 libgcc_s.so.1 => /mnt/hd/bld/gcc/gcc/libgcc_s.so.1 (0x400e5000) 1038 /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x00355000) 1039</computeroutput> 1040</screen> 1041 1042<para> 1043 This resulting binary, when executed, will be able to safely use 1044 code from both liba, and the dependent libstdc++.so.6, and libb, 1045 with the dependent libstdc++.so.5. 1046</para> 1047 </section> 1048</section> 1049 1050<section xml:id="abi.issues"><info><title>Outstanding Issues</title></info> 1051 1052 1053<para> 1054 Some features in the C++ language make versioning especially 1055 difficult. In particular, compiler generated constructs such as 1056 implicit instantiations for templates, typeinfo information, and 1057 virtual tables all may cause ABI leakage across shared library 1058 boundaries. Because of this, mixing C++ ABIs is not recommended at 1059 this time. 1060</para> 1061 1062<para> 1063 For more background on this issue, see these bugzilla entries: 1064</para> 1065 1066<para> 1067<link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://gcc.gnu.org/PR24660">24660: versioning weak symbols in libstdc++</link> 1068</para> 1069 1070<para> 1071<link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://gcc.gnu.org/PR19664">19664: libstdc++ headers should have pop/push of the visibility around the declarations</link> 1072</para> 1073 1074</section> 1075 1076<bibliography xml:id="abi.biblio"><info><title>Bibliography</title></info> 1077 1078 <biblioentry xml:id="biblio.abicheck"> 1079 <title> 1080 <link xmlns:xlink="http://www.w3.org/1999/xlink" 1081 xlink:href="http://abicheck.sourceforge.net"> 1082 ABIcheck 1083 </link> 1084 </title> 1085 </biblioentry> 1086 1087 <biblioentry xml:id="biblio.cxxabi"> 1088 <title> 1089 <link xmlns:xlink="http://www.w3.org/1999/xlink" 1090 xlink:href="http://mentorembedded.github.io/cxx-abi/"> 1091 C++ ABI Summary 1092 </link> 1093 </title> 1094 </biblioentry> 1095 1096 1097 <biblioentry> 1098 <title> 1099 <link xmlns:xlink="http://www.w3.org/1999/xlink" 1100 xlink:href="https://software.intel.com/en-us/articles/intel-compilers-for-linux-compatibility-with-gnu-compilers"> 1101 Intel Compilers for Linux: Compatibility with GNU Compilers 1102 </link> 1103 </title> 1104 </biblioentry> 1105 1106 <biblioentry> 1107 <title> 1108 <link xmlns:xlink="http://www.w3.org/1999/xlink" 1109 xlink:href="http://docs.oracle.com/cd/E23824_01/html/819-0690/index.html"> 1110 Linker and Libraries Guide (document 819-0690) 1111 </link> 1112 </title> 1113 </biblioentry> 1114 1115 1116 <biblioentry> 1117 <title> 1118 <link xmlns:xlink="http://www.w3.org/1999/xlink" 1119 xlink:href="http://download.oracle.com/docs/cd/E19422-01/819-3689/index.html"> 1120 Sun Studio 11: C++ Migration Guide (document 819-3689) 1121 </link> 1122 </title> 1123 </biblioentry> 1124 1125 <biblioentry> 1126 <title> 1127 <link xmlns:xlink="http://www.w3.org/1999/xlink" 1128 xlink:href="http://www.akkadia.org/drepper/dsohowto.pdf"> 1129 How to Write Shared Libraries 1130 </link> 1131 </title> 1132 1133 <author> 1134 <personname> 1135 <firstname>Ulrich</firstname><surname>Drepper</surname> 1136 </personname> 1137 </author> 1138 </biblioentry> 1139 1140 <biblioentry> 1141 <title> 1142 <link xmlns:xlink="http://www.w3.org/1999/xlink" 1143 xlink:href="http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ihi0036b/index.html"> 1144 C++ ABI for the ARM Architecture 1145 </link> 1146 </title> 1147 </biblioentry> 1148 1149 <biblioentry> 1150 <title> 1151 <link xmlns:xlink="http://www.w3.org/1999/xlink" 1152 xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2006/n1976.html"> 1153 Dynamic Shared Objects: Survey and Issues 1154 </link> 1155 </title> 1156 1157 <subtitle> 1158 ISO C++ J16/06-0046 1159 </subtitle> 1160 <author><personname><firstname>Benjamin</firstname><surname>Kosnik</surname></personname></author> 1161 </biblioentry> 1162 1163 <biblioentry> 1164 <title> 1165 <link xmlns:xlink="http://www.w3.org/1999/xlink" 1166 xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2006/n2013.html"> 1167 Versioning With Namespaces 1168 </link> 1169 </title> 1170 <subtitle> 1171 ISO C++ J16/06-0083 1172 </subtitle> 1173 <author><personname><firstname>Benjamin</firstname><surname>Kosnik</surname></personname></author> 1174 </biblioentry> 1175 1176 <biblioentry> 1177 <title> 1178 <link xmlns:xlink="http://www.w3.org/1999/xlink" 1179 xlink:href="http://syrcose.ispras.ru/2009/files/02_paper.pdf"> 1180 Binary Compatibility of Shared Libraries Implemented in C++ 1181 on GNU/Linux Systems 1182 </link> 1183 </title> 1184 1185 <subtitle> 1186 SYRCoSE 2009 1187 </subtitle> 1188 <author><personname><firstname>Pavel</firstname><surname>Shved</surname></personname></author> 1189 <author><personname><firstname>Denis</firstname><surname>Silakov</surname></personname></author> 1190 </biblioentry> 1191</bibliography> 1192 1193</section> 1194