1<?xml version="1.0" encoding="UTF-8" standalone="no"?> 2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3<html xmlns="http://www.w3.org/1999/xhtml"> 4 <head> 5 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> 6 <title>DbEnv::rep_set_transport()</title> 7 <link rel="stylesheet" href="apiReference.css" type="text/css" /> 8 <meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /> 9 <link rel="start" href="index.html" title="Berkeley DB C++ API Reference" /> 10 <link rel="up" href="rep.html" title="Chapter 11. Replication Methods" /> 11 <link rel="prev" href="repset_timeout.html" title="DbEnv::rep_set_timeout()" /> 12 <link rel="next" href="repstart.html" title="DbEnv::rep_start()" /> 13 </head> 14 <body> 15 <div class="navheader"> 16 <table width="100%" summary="Navigation header"> 17 <tr> 18 <th colspan="3" align="center">DbEnv::rep_set_transport()</th> 19 </tr> 20 <tr> 21 <td width="20%" align="left"><a accesskey="p" href="repset_timeout.html">Prev</a> </td> 22 <th width="60%" align="center">Chapter 11. 23 Replication Methods 24 </th> 25 <td width="20%" align="right"> <a accesskey="n" href="repstart.html">Next</a></td> 26 </tr> 27 </table> 28 <hr /> 29 </div> 30 <div class="sect1" lang="en" xml:lang="en"> 31 <div class="titlepage"> 32 <div> 33 <div> 34 <h2 class="title" style="clear: both"><a id="reptransport"></a>DbEnv::rep_set_transport()</h2> 35 </div> 36 </div> 37 </div> 38 <pre class="programlisting">#include <db_cxx.h> 39 40int 41DbEnv::rep_set_transport(int envid, 42 int (*send)(DB_ENV *dbenv, 43 const Dbt *control, const Dbt *rec, const DbLsn *lsnp, 44 int envid, u_int32_t flags));</pre> 45 <p> 46 The <code class="methodname">DbEnv::rep_set_transport()</code> method initializes the communication 47 infrastructure for a database environment participating in a replicated application. 48 </p> 49 <p> 50 The <code class="methodname">DbEnv::rep_set_transport()</code> method is not called by most 51 replication applications. It should only be called by Base API applications 52 implementing their own network transport layer, explicitly holding 53 replication group elections and handling replication messages outside 54 of the Replication Manager framework. 55 </p> 56 <p> 57 The <code class="methodname">DbEnv::rep_set_transport()</code> method configures operations 58 performed using the specified <a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a> handle, 59 not all operations performed on the underlying database environment. 60 </p> 61 <p> 62 The <code class="methodname">DbEnv::rep_set_transport()</code> method may be called at any time 63 during the life of the application. 64 </p> 65 <p> 66 The <code class="methodname">DbEnv::rep_set_transport()</code> <span> 67 68 <span> 69 method either returns a non-zero error value or throws an 70 exception that encapsulates a non-zero error value on 71 failure, and returns 0 on success. 72 </span> 73 </span> 74 </p> 75 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"> 76 <h3 class="title">Note</h3> 77 <p> 78 Berkeley DB is not re-entrant. The callback function 79for this method should not attempt to make 80 library calls (for example, to release locks or close open handles). Re-entering 81 Berkeley DB is not guaranteed to work correctly, and the results are undefined. 82 </p> 83 </div> 84 <div class="sect2" lang="en" xml:lang="en"> 85 <div class="titlepage"> 86 <div> 87 <div> 88 <h3 class="title"><a id="id1703770"></a>Parameters</h3> 89 </div> 90 </div> 91 </div> 92 <div class="sect3" lang="en" xml:lang="en"> 93 <div class="titlepage"> 94 <div> 95 <div> 96 <h4 class="title"><a id="id1704762"></a>envid</h4> 97 </div> 98 </div> 99 </div> 100 <p> 101 The <span class="bold"><strong>envid</strong></span> parameter is the local 102 environment's ID. It must be a non-negative integer and uniquely identify 103 this Berkeley DB database environment (see 104 <a href="../../programmer_reference/rep_id.html" class="olink">Replication environment IDs</a> 105 for more information). 106 </p> 107 </div> 108 <div class="sect3" lang="en" xml:lang="en"> 109 <div class="titlepage"> 110 <div> 111 <div> 112 <h4 class="title"><a id="id1704895"></a>send</h4> 113 </div> 114 </div> 115 </div> 116 <p> 117 The <span class="bold"><strong>send</strong></span> callback function is used to 118 transmit data using the replication application's communication 119 infrastructure. The parameters to <span class="bold"><strong>send</strong></span> are as follows: 120 </p> 121 <div class="itemizedlist"> 122 <ul type="disc"> 123 <li> 124 <p> 125 <code class="literal">dbenv</code> 126 </p> 127 <p> 128 The <span class="bold"><strong>dbenv</strong></span> parameter is the enclosing 129 database environment handle. 130 </p> 131 </li> 132 <li> 133 <p> 134 <code class="literal">control</code> 135 </p> 136 <p> 137 The <span class="bold"><strong>control</strong></span> parameter is the first of 138 the two data elements to be transmitted by the <span class="bold"><strong>send</strong></span> function. 139 </p> 140 </li> 141 <li> 142 <p> 143 <code class="literal">rec</code> 144 </p> 145 <p> 146 The <span class="bold"><strong>rec</strong></span> parameter is the second of 147 the two data elements to be transmitted by the <span class="bold"><strong>send</strong></span> function. 148 </p> 149 </li> 150 <li> 151 <p> 152 <code class="literal">lsnp</code> 153 </p> 154 <p> 155 If the type of message to be sent has an LSN associated with it, then 156 the <span class="bold"><strong>lsnp</strong></span> parameter contains the LSN 157 of the record being sent. This LSN can be used to determine that 158 certain records have been processed successfully by clients. 159 </p> 160 </li> 161 <li> 162 <p> 163 <code class="literal">envid</code> 164 </p> 165 <p> 166 The <span class="bold"><strong>envid</strong></span> parameter is a positive 167 integer identifier that specifies the replication environment to which 168 the message should be sent (see <a href="../../programmer_reference/rep_id.html" class="olink">Replication environment IDs</a> for more 169 information). 170 </p> 171 <p><a id="transport_DB_EID_BROADCAST"></a> 172 The special identifier <code class="literal">DB_EID_BROADCAST</code> indicates that a message 173 should be broadcast to every environment in the replication group. The application 174 may use a true broadcast protocol or may send the message in sequence to each 175 machine with which it is in communication. In both cases, the sending site should 176 not be asked to process the message. 177 </p> 178 <p> 179 The special identifier 180 <a href="../../programmer_reference/rep_id.html#rep_id.DB_EID_INVALID" class="olink">DB_EID_INVALID</a> 181 indicates an invalid environment ID. This may be used to initialize 182 values that are subsequently checked for validity. 183 </p> 184 </li> 185 <li> 186 <p> 187 <code class="literal">flags</code> 188 </p> 189 <p> 190 The <span class="bold"><strong>flags</strong></span> parameter must be set to 0 191 or by bitwise inclusively <span class="bold"><strong>OR</strong></span>'ing 192 together one or more of the following values: 193 </p> 194 <div class="itemizedlist"> 195 <ul type="circle"> 196 <li> 197 <p><a id="transport_DB_REP_ANYWHERE"></a> 198 <code class="literal">DB_REP_ANYWHERE</code> 199 </p> 200 <p> 201 The message is a client request that can be satisfied by another 202 client as well as by the master. 203 </p> 204 </li> 205 <li> 206 <p><a id="transport_DB_REP_NOBUFFER"></a> 207 <code class="literal">DB_REP_NOBUFFER</code> 208 </p> 209 <p> 210 The record being sent should be transmitted immediately and not 211 buffered or delayed. 212 </p> 213 </li> 214 <li> 215 <p><a id="transport_DB_REP_PERMANENT"></a> 216 <code class="literal">DB_REP_PERMANENT</code> 217 </p> 218 <p> 219 The record being sent is critical for maintaining database integrity 220 (for example, the message includes a transaction commit). The 221 application should take appropriate action to enforce the reliability 222 guarantees it has chosen, such as waiting for acknowledgement from one 223 or more clients. 224 </p> 225 </li> 226 <li> 227 <p><a id="transport_DB_REP_REREQUEST"></a> 228 <code class="literal">DB_REP_REREQUEST</code> 229 </p> 230 <p> 231 The message is a client request that has already been made and to 232 which no response was received. 233 </p> 234 </li> 235 </ul> 236 </div> 237 </li> 238 </ul> 239 </div> 240 <p> 241 242 It may sometimes be useful to pass application-specific data to the send 243 function; see <a href="../../programmer_reference/env_faq.html" class="olink">Environment FAQ</a> 244 for a discussion on how to do this. 245 246 </p> 247 <p> 248 The <span class="bold"><strong>send</strong></span> function must return 0 on success and non-zero on failure. 249 If the send function fails, the message being sent is necessary to maintain database integrity, and 250 the local log is not configured for synchronous flushing, the local log will be flushed; otherwise, 251 any error from the <span class="bold"><strong>send</strong></span> function will be ignored. 252 </p> 253 </div> 254 </div> 255 <div class="sect2" lang="en" xml:lang="en"> 256 <div class="titlepage"> 257 <div> 258 <div> 259 <h3 class="title"><a id="id1704926"></a>Errors</h3> 260 </div> 261 </div> 262 </div> 263 <p> 264 The <code class="methodname">DbEnv::rep_set_transport()</code> <span> 265 266 <span> 267 method may fail and throw a <a class="link" href="dbexception.html" title="Chapter 6. The DbException Class">DbException</a> 268 exception, encapsulating one of the following non-zero errors, or return one 269 of the following non-zero errors: 270 </span> 271 </span> 272 </p> 273 <div class="sect3" lang="en" xml:lang="en"> 274 <div class="titlepage"> 275 <div> 276 <div> 277 <h4 class="title"><a id="id1705322"></a>EINVAL</h4> 278 </div> 279 </div> 280 </div> 281 <p> 282 The method is called from a Replication Manager application; or an invalid flag value or 283 parameter was specified. 284 </p> 285 </div> 286 </div> 287 <div class="sect2" lang="en" xml:lang="en"> 288 <div class="titlepage"> 289 <div> 290 <div> 291 <h3 class="title"><a id="id1704691"></a>Class</h3> 292 </div> 293 </div> 294 </div> 295 <p> 296 <a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a> 297 </p> 298 </div> 299 <div class="sect2" lang="en" xml:lang="en"> 300 <div class="titlepage"> 301 <div> 302 <div> 303 <h3 class="title"><a id="id1704564"></a>See Also</h3> 304 </div> 305 </div> 306 </div> 307 <p> 308 <a class="xref" href="rep.html#replist" title="Replication and Related Methods">Replication and Related Methods</a> 309 </p> 310 </div> 311 </div> 312 <div class="navfooter"> 313 <hr /> 314 <table width="100%" summary="Navigation footer"> 315 <tr> 316 <td width="40%" align="left"><a accesskey="p" href="repset_timeout.html">Prev</a> </td> 317 <td width="20%" align="center"> 318 <a accesskey="u" href="rep.html">Up</a> 319 </td> 320 <td width="40%" align="right"> <a accesskey="n" href="repstart.html">Next</a></td> 321 </tr> 322 <tr> 323 <td width="40%" align="left" valign="top">DbEnv::rep_set_timeout() </td> 324 <td width="20%" align="center"> 325 <a accesskey="h" href="index.html">Home</a> 326 </td> 327 <td width="40%" align="right" valign="top"> DbEnv::rep_start()</td> 328 </tr> 329 </table> 330 </div> 331 </body> 332</html> 333