<?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>DbEnv::repmgr_msg_dispatch()</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 11. 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Replication Methods </th> <td width="20%" align="right"> <a accesskey="n" href="repmgrset_ack_policy.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="repmgr_msg_dispatch"></a>DbEnv::repmgr_msg_dispatch()</h2> </div> </div> </div> <pre class="programlisting">#include <db_cxx.h> int DbEnv::repmgr_msg_dispatch( void (*msg_dispatch_fcn) (DbEnv *env, DbChannel *channel, Dbt *request, u_int32_t nrequest, u_int32_t cb_flags), u_int32_t flags); </pre> <p> Sets the message dispatch function. This function is responsible for receiving messages sent from remote sites using either the <a class="xref" href="dbchannel_send_msg.html" title="DbChannel::send_msg()">DbChannel::send_msg()</a> or <a class="xref" href="dbchannel_send_request.html" title="DbChannel::send_request()">DbChannel::send_request()</a> methods. If the message received by this function was sent using the <a class="xref" href="dbchannel_send_msg.html" title="DbChannel::send_msg()">DbChannel::send_msg()</a> method then no response is required. If the message was sent using the <a class="xref" href="dbchannel_send_request.html" title="DbChannel::send_request()">DbChannel::send_request()</a> method, then this function must send a response using the <a class="xref" href="dbchannel_send_msg.html" title="DbChannel::send_msg()">DbChannel::send_msg()</a> method. </p> <p> For best results, the <code class="methodname">DbEnv::repmgr_msg_dispatch()</code> method should be called before the Replication Manager has been started. </p> <p> The <code class="methodname">DbEnv::repmgr_msg_dispatch()</code> <span> <span> method either returns a non-zero error value or throws an exception that encapsulates a non-zero error value on failure, and returns 0 on success. </span> </span> </p> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp9871312"></a>Parameters</h3> </div> </div> </div> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h4 class="title"><a id="idp9870664"></a>msg_dispatch_fcn</h4> </div> </div> </div> <p> This parameter is the application-specific function used to handle messages sent over Replication Manager message channels. It takes four parameters: </p> <div class="itemizedlist"> <ul type="disc"> <li> <p> <code class="literal">channel</code> </p> <p> Provides the DbChannel to be used to send a response back to the originator of the message. If the message was sent by the remote site using <a class="xref" href="dbchannel_send_request.html" title="DbChannel::send_request()">DbChannel::send_request()</a> then this function should send a response back to the originator using the channel provided on this parameter. The message should be sent by calling <a class="xref" href="dbchannel_send_msg.html" title="DbChannel::send_msg()">DbChannel::send_msg()</a> exactly once. </p> <p> This channel is valid only during the current invocation of the dispatch function; it is destroyed when the dispatch function returns. The application may not save a copy of the pointer and use it later elsewhere. Methods that do not make sense in the context of a message dispatch function (such as <a class="xref" href="dbchannel_send_request.html" title="DbChannel::send_request()">DbChannel::send_request()</a> and <a class="xref" href="dbchannel_close.html" title="DbChannel::close()">DbChannel::close()</a>) will be rejected with <code class="literal">EINVAL</code>. </p> </li> <li> <p> <code class="literal">request</code> </p> <p> Array of Dbts containing the message received from the remote site. </p> </li> <li> <p> <code class="literal">nrequest</code> </p> <p> Specifies the number of elements in the <code class="literal">request</code> array. </p> </li> <li> <p> <code class="literal">cb_flags</code> </p> <p> This flag is <code class="literal">DB_REPMGR_NEED_RESPONSE</code> if the message requires a response. Otherwise, it is <code class="literal">0</code>. </p> </li> </ul> </div> <p> This function does not return a value. If the function encounters an error, you can reflect the error back to the originator of the message by formatting an error message of your own design into the response. </p> </div> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h4 class="title"><a id="idp9883704"></a>flags</h4> </div> </div> </div> <p> This parameter is currently unused, and must be set to 0. </p> </div> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp9877984"></a>Errors</h3> </div> </div> </div> <p> The <code class="methodname">DbEnv::repmgr_msg_dispatch()</code> <span> <span> method may fail and throw a <a class="link" href="dbexception.html" title="Chapter 6. The DbException Class">DbException</a> exception, encapsulating one of the following non-zero errors, or 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="idp9881048"></a>EINVAL</h4> </div> </div> </div> <p> If this method is called from a Base API application, or if 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="idp9889232"></a>Class</h3> </div> </div> </div> <p> <a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a> </p> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp9886080"></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="repmgrget_ack_policy.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="repmgrset_ack_policy.html">Next</a></td> </tr> <tr> <td width="40%" align="left" valign="top">DbEnv::repmgr_get_ack_policy() </td> <td width="20%" align="center"> <a accesskey="h" href="index.html">Home</a> </td> <td width="40%" align="right" valign="top"> DbEnv::repmgr_set_ack_policy()</td> </tr> </table> </div> </body> </html>