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::mutex_lock()</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="mutex.html" title="Chapter 10. Mutex Methods" /> 11 <link rel="prev" href="mutexget_tas_spins.html" title="DbEnv::mutex_get_tas_spins()" /> 12 <link rel="next" href="mutexset_align.html" title="DbEnv::mutex_set_align()" /> 13 </head> 14 <body> 15 <div class="navheader"> 16 <table width="100%" summary="Navigation header"> 17 <tr> 18 <th colspan="3" align="center">DbEnv::mutex_lock()</th> 19 </tr> 20 <tr> 21 <td width="20%" align="left"><a accesskey="p" href="mutexget_tas_spins.html">Prev</a> </td> 22 <th width="60%" align="center">Chapter 10. 23 Mutex Methods 24 </th> 25 <td width="20%" align="right"> <a accesskey="n" href="mutexset_align.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="mutexlock"></a>DbEnv::mutex_lock()</h2> 35 </div> 36 </div> 37 </div> 38 <pre class="programlisting">#include <db_cxx.h> 39 40int 41DbEnv::mutex_lock(db_mutex_t mutex);</pre> 42 <p> 43 The <code class="methodname">DbEnv::mutex_lock()</code> method locks the mutex allocated by 44 <a class="xref" href="mutexalloc.html" title="DbEnv::mutex_alloc()">DbEnv::mutex_alloc()</a>. The 45 thread of control calling <code class="methodname">DbEnv::mutex_lock()</code> will block until the 46 lock is available. 47 </p> 48 <p> 49 The <code class="methodname">DbEnv::mutex_lock()</code> <span> 50 51 <span> 52 method either returns a non-zero error value or throws an 53 exception that encapsulates a non-zero error value on 54 failure, and returns 0 on success. 55 </span> 56 </span> 57 </p> 58 <div class="sect2" lang="en" xml:lang="en"> 59 <div class="titlepage"> 60 <div> 61 <div> 62 <h3 class="title"><a id="id1698759"></a>Parameters</h3> 63 </div> 64 </div> 65 </div> 66 <div class="sect3" lang="en" xml:lang="en"> 67 <div class="titlepage"> 68 <div> 69 <div> 70 <h4 class="title"><a id="id1698817"></a>mutex</h4> 71 </div> 72 </div> 73 </div> 74 <p> 75 The <span class="bold"><strong>mutex</strong></span> parameter is a mutex 76 previously allocated by <a class="xref" href="mutexalloc.html" title="DbEnv::mutex_alloc()">DbEnv::mutex_alloc()</a>. 77 </p> 78 </div> 79 </div> 80 <div class="sect2" lang="en" xml:lang="en"> 81 <div class="titlepage"> 82 <div> 83 <div> 84 <h3 class="title"><a id="id1698977"></a>Errors</h3> 85 </div> 86 </div> 87 </div> 88 <p> 89 The <code class="methodname">DbEnv::mutex_lock()</code> <span> 90 91 <span> 92 method may fail and throw a <a class="link" href="dbexception.html" title="Chapter 6. The DbException Class">DbException</a> 93 exception, encapsulating one of the following non-zero errors, or return one 94 of the following non-zero errors: 95 </span> 96 </span> 97 </p> 98 <div class="sect3" lang="en" xml:lang="en"> 99 <div class="titlepage"> 100 <div> 101 <div> 102 <h4 class="title"><a id="id1698732"></a>EINVAL</h4> 103 </div> 104 </div> 105 </div> 106 <p> 107 An invalid flag value or parameter was specified. 108 </p> 109 </div> 110 </div> 111 <div class="sect2" lang="en" xml:lang="en"> 112 <div class="titlepage"> 113 <div> 114 <div> 115 <h3 class="title"><a id="id1698969"></a>Class</h3> 116 </div> 117 </div> 118 </div> 119 <p> 120 <a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a> 121 </p> 122 </div> 123 <div class="sect2" lang="en" xml:lang="en"> 124 <div class="titlepage"> 125 <div> 126 <div> 127 <h3 class="title"><a id="id1698496"></a>See Also</h3> 128 </div> 129 </div> 130 </div> 131 <p> 132 <a class="xref" href="mutex.html#mutexlist" title="Mutex Methods">Mutex Methods</a> 133 </p> 134 </div> 135 </div> 136 <div class="navfooter"> 137 <hr /> 138 <table width="100%" summary="Navigation footer"> 139 <tr> 140 <td width="40%" align="left"><a accesskey="p" href="mutexget_tas_spins.html">Prev</a> </td> 141 <td width="20%" align="center"> 142 <a accesskey="u" href="mutex.html">Up</a> 143 </td> 144 <td width="40%" align="right"> <a accesskey="n" href="mutexset_align.html">Next</a></td> 145 </tr> 146 <tr> 147 <td width="40%" align="left" valign="top">DbEnv::mutex_get_tas_spins() </td> 148 <td width="20%" align="center"> 149 <a accesskey="h" href="index.html">Home</a> 150 </td> 151 <td width="40%" align="right" valign="top"> DbEnv::mutex_set_align()</td> 152 </tr> 153 </table> 154 </div> 155 </body> 156</html> 157