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::log_get_config()</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="lsn.html" title="Chapter 8. The DbLsn Handle" /> 11 <link rel="prev" href="logflush.html" title="DbEnv::log_flush()" /> 12 <link rel="next" href="logprintf.html" title="DbEnv::log_printf()" /> 13 </head> 14 <body> 15 <div class="navheader"> 16 <table width="100%" summary="Navigation header"> 17 <tr> 18 <th colspan="3" align="center">DbEnv::log_get_config()</th> 19 </tr> 20 <tr> 21 <td width="20%" align="left"><a accesskey="p" href="logflush.html">Prev</a> </td> 22 <th width="60%" align="center">Chapter 8. 23 The DbLsn Handle 24 </th> 25 <td width="20%" align="right"> <a accesskey="n" href="logprintf.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="envlog_get_config"></a>DbEnv::log_get_config()</h2> 35 </div> 36 </div> 37 </div> 38 <pre class="programlisting">#include <db_cxx.h> 39 40int 41DbEnv::log_get_config(u_int32_t which, int *onoffp)</pre> 42 <p> 43 The <code class="methodname">DbEnv::log_get_config()</code> method returns whether the specified 44 <span class="bold"><strong>which</strong></span> parameter is currently set or 45 not. You can manage this value using the 46 <a class="xref" href="envlog_set_config.html" title="DbEnv::log_set_config()">DbEnv::log_set_config()</a> 47 method. 48 </p> 49 <p> 50 The <code class="methodname">DbEnv::log_get_config()</code> method may be called at any time during 51 the life of the application. 52 </p> 53 <p> 54 The <code class="methodname">DbEnv::log_get_config()</code> <span> 55 56 <span> 57 method either returns a non-zero error value or throws an 58 exception that encapsulates a non-zero error value on 59 failure, and returns 0 on success. 60 </span> 61 </span> 62 </p> 63 <div class="sect2" lang="en" xml:lang="en"> 64 <div class="titlepage"> 65 <div> 66 <div> 67 <h3 class="title"><a id="id1685734"></a>Parameters</h3> 68 </div> 69 </div> 70 </div> 71 <div class="sect3" lang="en" xml:lang="en"> 72 <div class="titlepage"> 73 <div> 74 <div> 75 <h4 class="title"><a id="id1685315"></a>which</h4> 76 </div> 77 </div> 78 </div> 79 <p> 80 The <span class="bold"><strong>which</strong></span> parameter is the message 81 value for which configuration is being checked. Must be set to one of the following values: 82 </p> 83 <div class="itemizedlist"> 84 <ul type="disc"> 85 <li> 86 <p><a id="log_get_config_DB_LOG_DIRECT"></a> 87 <code class="literal">DB_LOG_DIRECT</code> 88 </p> 89 <p> 90 System buffering is turned off for Berkeley DB log files to avoid double 91 caching. 92 </p> 93 </li> 94 <li> 95 <p><a id="log_get_config_DB_LOG_DSYNC"></a> 96 <code class="literal">DB_LOG_DSYNC</code> 97 </p> 98 <p> 99 Berkeley DB is configured to flush log writes to the backing disk before 100 returning from the write system call, rather than flushing log writes 101 explicitly in a separate system call, as necessary. 102 </p> 103 </li> 104 <li> 105 <p><a id="log_get_config_DB_LOG_AUTO_REMOVE"></a> 106 <code class="literal">DB_LOG_AUTO_REMOVE</code> 107 </p> 108 <p> 109 Berkeley DB automatically removes log files that are no 110 longer needed. 111 </p> 112 </li> 113 <li> 114 <p><a id="log_get_config_DB_LOG_IN_MEMORY"></a> 115 <code class="literal">DB_LOG_IN_MEMORY</code> 116 </p> 117 <p> 118 Transaction logs are maintained in memory rather than on disk. This 119 means that transactions exhibit the ACI (atomicity, consistency, and 120 isolation) properties, but not D (durability). 121 </p> 122 </li> 123 <li> 124 <p><a id="log_get_config_DB_LOG_ZERO"></a> 125 <code class="literal">DB_LOG_ZERO</code> 126 </p> 127 <p> 128 All pages of a log file are zeroed when that log file is created. 129 </p> 130 </li> 131 </ul> 132 </div> 133 </div> 134 <div class="sect3" lang="en" xml:lang="en"> 135 <div class="titlepage"> 136 <div> 137 <div> 138 <h4 class="title"><a id="id1685735"></a>onoffp</h4> 139 </div> 140 </div> 141 </div> 142 <p> 143 The <span class="bold"><strong>onoffp</strong></span> parameter references 144 memory into which the configuration of the specified <span class="bold"><strong>which</strong></span> parameter is copied. 145 </p> 146 <p> 147 If the returned <span class="bold"><strong>onoff</strong></span> value is zero, the 148 parameter is off; otherwise, on. 149 </p> 150 </div> 151 </div> 152 <div class="sect2" lang="en" xml:lang="en"> 153 <div class="titlepage"> 154 <div> 155 <div> 156 <h3 class="title"><a id="id1685910"></a>Class</h3> 157 </div> 158 </div> 159 </div> 160 <p> 161 <a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a> 162 </p> 163 </div> 164 <div class="sect2" lang="en" xml:lang="en"> 165 <div class="titlepage"> 166 <div> 167 <div> 168 <h3 class="title"><a id="id1686124"></a>See Also</h3> 169 </div> 170 </div> 171 </div> 172 <p> 173 <a class="xref" href="lsn.html#loglist" title="Logging Subsystem and Related Methods">Logging Subsystem and Related Methods</a>, 174 <a class="xref" href="envlog_set_config.html" title="DbEnv::log_set_config()">DbEnv::log_set_config()</a> 175 </p> 176 </div> 177 </div> 178 <div class="navfooter"> 179 <hr /> 180 <table width="100%" summary="Navigation footer"> 181 <tr> 182 <td width="40%" align="left"><a accesskey="p" href="logflush.html">Prev</a> </td> 183 <td width="20%" align="center"> 184 <a accesskey="u" href="lsn.html">Up</a> 185 </td> 186 <td width="40%" align="right"> <a accesskey="n" href="logprintf.html">Next</a></td> 187 </tr> 188 <tr> 189 <td width="40%" align="left" valign="top">DbEnv::log_flush() </td> 190 <td width="20%" align="center"> 191 <a accesskey="h" href="index.html">Home</a> 192 </td> 193 <td width="40%" align="right" valign="top"> DbEnv::log_printf()</td> 194 </tr> 195 </table> 196 </div> 197 </body> 198</html> 199