<?xml version="1.0" encoding="UTF-8" standalone="no"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> <title>DB_ENV->rep_set_transport()</title> <link rel="stylesheet" href="apiReference.css" type="text/css" /> <meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /> <link rel="start" href="index.html" title="Berkeley DB C API Reference" /> <link rel="up" href="rep.html" title="Chapter 10. Replication Methods" /> <link rel="prev" href="repset_timeout.html" title="DB_ENV->rep_set_timeout()" /> <link rel="next" href="repstart.html" title="DB_ENV->rep_start()" /> </head> <body> <div xmlns="" class="navheader"> <div class="libver"> <p>Library Version 11.2.5.3</p> </div> <table width="100%" summary="Navigation header"> <tr> <th colspan="3" align="center">DB_ENV->rep_set_transport()</th> </tr> <tr> <td width="20%" align="left"><a accesskey="p" href="repset_timeout.html">Prev</a> </td> <th width="60%" align="center">Chapter 10. Replication Methods </th> <td width="20%" align="right"> <a accesskey="n" href="repstart.html">Next</a></td> </tr> </table> <hr /> </div> <div class="sect1" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h2 class="title" style="clear: both"><a id="reptransport"></a>DB_ENV->rep_set_transport()</h2> </div> </div> </div> <pre class="programlisting">#include <db.h> int DB_ENV->rep_set_transport(DB_ENV *env, int envid, int (*send)(DB_ENV *dbenv, const DBT *control, const DBT *rec, const DB_LSN *lsnp, int envid, u_int32_t flags)); </pre> <p> The <code class="methodname">DB_ENV->rep_set_transport()</code> method initializes the communication infrastructure for a database environment participating in a replicated application. </p> <p> The <code class="methodname">DB_ENV->rep_set_transport()</code> method is not called by most replication applications. It should only be called by Base API applications implementing their own network transport layer, explicitly holding replication group elections and handling replication messages outside of the Replication Manager framework. </p> <p> The <code class="methodname">DB_ENV->rep_set_transport()</code> method configures operations performed using the specified <a class="link" href="env.html" title="Chapter 5. The DB_ENV Handle">DB_ENV</a> handle, not all operations performed on the underlying database environment. </p> <p> The <code class="methodname">DB_ENV->rep_set_transport()</code> method may be called at any time during the life of the application. </p> <p> The <code class="methodname">DB_ENV->rep_set_transport()</code> <span> <span> method returns a non-zero error value on failure and 0 on success. </span> </span> </p> <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"> <h3 class="title">Note</h3> <p> Berkeley DB is not re-entrant. The callback function for this method should not attempt to make library calls (for example, to release locks or close open handles). Re-entering Berkeley DB is not guaranteed to work correctly, and the results are undefined. </p> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp54196216"></a>Parameters</h3> </div> </div> </div> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h4 class="title"><a id="idp54196560"></a>envid</h4> </div> </div> </div> <p> The <span class="bold"><strong>envid</strong></span> parameter is the local environment's ID. It must be a non-negative integer and uniquely identify this Berkeley DB database environment (see <a href="../../programmer_reference/rep_id.html" class="olink">Replication environment IDs</a> for more information). </p> </div> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h4 class="title"><a id="idp54206528"></a>send</h4> </div> </div> </div> <p> The <span class="bold"><strong>send</strong></span> callback function is used to transmit data using the replication application's communication infrastructure. The parameters to <span class="bold"><strong>send</strong></span> are as follows: </p> <div class="itemizedlist"> <ul type="disc"> <li> <p> <code class="literal">dbenv</code> </p> <p> The <span class="bold"><strong>dbenv</strong></span> parameter is the enclosing database environment handle. </p> </li> <li> <p> <code class="literal">control</code> </p> <p> The <span class="bold"><strong>control</strong></span> parameter is the first of the two data elements to be transmitted by the <span class="bold"><strong>send</strong></span> function. </p> </li> <li> <p> <code class="literal">rec</code> </p> <p> The <span class="bold"><strong>rec</strong></span> parameter is the second of the two data elements to be transmitted by the <span class="bold"><strong>send</strong></span> function. </p> </li> <li> <p> <code class="literal">lsnp</code> </p> <p> If the type of message to be sent has an LSN associated with it, then the <span class="bold"><strong>lsnp</strong></span> parameter contains the LSN of the record being sent. This LSN can be used to determine that certain records have been processed successfully by clients. </p> </li> <li> <p> <code class="literal">envid</code> </p> <p> The <span class="bold"><strong>envid</strong></span> parameter is a positive integer identifier that specifies the replication environment to which the message should be sent (see <a href="../../programmer_reference/rep_id.html" class="olink">Replication environment IDs</a> for more information). </p> <p><a id="transport_DB_EID_BROADCAST"></a> The special identifier <code class="literal">DB_EID_BROADCAST</code> indicates that a message should be broadcast to every environment in the replication group. The application may use a true broadcast protocol or may send the message in sequence to each machine with which it is in communication. In both cases, the sending site should not be asked to process the message. </p> <p> The special identifier <a href="../../programmer_reference/rep_id.html#rep_id.DB_EID_INVALID" class="olink">DB_EID_INVALID</a> indicates an invalid environment ID. This may be used to initialize values that are subsequently checked for validity. </p> </li> <li> <p> <code class="literal">flags</code> </p> <p> The <span class="bold"><strong>flags</strong></span> parameter must be set to 0 or by bitwise inclusively <span class="bold"><strong>OR</strong></span>'ing together one or more of the following values: </p> <div class="itemizedlist"> <ul type="circle"> <li> <p><a id="transport_DB_REP_ANYWHERE"></a> <code class="literal">DB_REP_ANYWHERE</code> </p> <p> The message is a client request that can be satisfied by another client as well as by the master. </p> </li> <li> <p><a id="transport_DB_REP_NOBUFFER"></a> <code class="literal">DB_REP_NOBUFFER</code> </p> <p> The record being sent should be transmitted immediately and not buffered or delayed. </p> </li> <li> <p><a id="transport_DB_REP_PERMANENT"></a> <code class="literal">DB_REP_PERMANENT</code> </p> <p> The record being sent is critical for maintaining database integrity (for example, the message includes a transaction commit). The application should take appropriate action to enforce the reliability guarantees it has chosen, such as waiting for acknowledgement from one or more clients. </p> </li> <li> <p><a id="transport_DB_REP_REREQUEST"></a> <code class="literal">DB_REP_REREQUEST</code> </p> <p> The message is a client request that has already been made and to which no response was received. </p> </li> </ul> </div> </li> </ul> </div> <p> It may sometimes be useful to pass application-specific data to the send function; see <a href="../../programmer_reference/env_faq.html" class="olink">Environment FAQ</a> for a discussion on how to do this. </p> <p> The <span class="bold"><strong>send</strong></span> function must return 0 on success and non-zero on failure. If the send function fails, the message being sent is necessary to maintain database integrity, and the local log is not configured for synchronous flushing, the local log will be flushed; otherwise, any error from the <span class="bold"><strong>send</strong></span> function will be ignored. </p> </div> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp54234360"></a>Errors</h3> </div> </div> </div> <p> The <code class="methodname">DB_ENV->rep_set_transport()</code> <span> <span> method may fail and return one of the following non-zero errors: </span> </span> </p> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h4 class="title"><a id="idp54253232"></a>EINVAL</h4> </div> </div> </div> <p> The method is called from a Replication Manager application; or an invalid flag value or parameter was specified. </p> </div> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp54205664"></a>Class</h3> </div> </div> </div> <p> <a class="link" href="env.html" title="Chapter 5. The DB_ENV Handle">DB_ENV</a> </p> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp54216040"></a>See Also</h3> </div> </div> </div> <p> <a class="xref" href="rep.html#replist" title="Replication and Related Methods">Replication and Related Methods</a> </p> </div> </div> <div class="navfooter"> <hr /> <table width="100%" summary="Navigation footer"> <tr> <td width="40%" align="left"><a accesskey="p" href="repset_timeout.html">Prev</a> </td> <td width="20%" align="center"> <a accesskey="u" href="rep.html">Up</a> </td> <td width="40%" align="right"> <a accesskey="n" href="repstart.html">Next</a></td> </tr> <tr> <td width="40%" align="left" valign="top">DB_ENV->rep_set_timeout() </td> <td width="20%" align="center"> <a accesskey="h" href="index.html">Home</a> </td> <td width="40%" align="right" valign="top"> DB_ENV->rep_start()</td> </tr> </table> </div> </body> </html>