<?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::log_file()</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="lsn.html" title="Chapter 8. The DbLsn Handle" /> <link rel="prev" href="logcursor.html" title="DbEnv::log_cursor()" /> <link rel="next" href="logflush.html" title="DbEnv::log_flush()" /> </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">DbEnv::log_file()</th> </tr> <tr> <td width="20%" align="left"><a accesskey="p" href="logcursor.html">Prev</a> </td> <th width="60%" align="center">Chapter 8. The DbLsn Handle </th> <td width="20%" align="right"> <a accesskey="n" href="logflush.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="logfile"></a>DbEnv::log_file()</h2> </div> </div> </div> <pre class="programlisting">#include <db_cxx.h> int DbEnv::log_file(const DbLsn *lsn, char *namep, size_t len);</pre> <p> The <code class="methodname">DbEnv::log_file()</code> method maps <code class="classname">DbLsn</code> structures to filenames, returning the name of the file containing the record named by <span class="bold"><strong>lsn</strong></span>. </p> <p> This mapping of <code class="classname">DbLsn</code> structures to files is needed for database administration. For example, a transaction manager typically records the earliest <a class="link" href="lsn.html" title="Chapter 8. The DbLsn Handle">DbLsn</a> needed for restart, and the database administrator may want to archive log files to tape when they contain only <a class="link" href="lsn.html" title="Chapter 8. The DbLsn Handle">DbLsn</a> entries before the earliest one needed for restart. </p> <p> The <code class="methodname">DbEnv::log_file()</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="idp2952192"></a>Parameters</h3> </div> </div> </div> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h4 class="title"><a id="idp2951544"></a>lsn</h4> </div> </div> </div> <p> The <span class="bold"><strong>lsn</strong></span> parameter is the <code class="classname">DbLsn</code> structure for which a filename is wanted. </p> </div> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h4 class="title"><a id="idp2938640"></a>namep</h4> </div> </div> </div> <p> The <span class="bold"><strong>namep</strong></span> parameter references memory into which the name of the file containing the record named by <span class="bold"><strong>lsn</strong></span> is copied. </p> </div> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h4 class="title"><a id="idp2914344"></a>len</h4> </div> </div> </div> <p> The <span class="bold"><strong>len</strong></span> parameter is the length of the <span class="bold"><strong>namep</strong></span> buffer in bytes. If <span class="bold"><strong>namep</strong></span> is too short to hold the filename, <code class="methodname">DbEnv::log_file()</code> will fail. (Log filenames are always 14 characters long.) </p> </div> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp2949160"></a>Errors</h3> </div> </div> </div> <p> The <code class="methodname">DbEnv::log_file()</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="idp2960392"></a>EINVAL</h4> </div> </div> </div> <p> If supplied buffer was too small to hold the log filename; 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="idp2958632"></a>Class</h3> </div> </div> </div> <p> <a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a>, <a class="link" href="logc.html" title="The DbLogc Handle">DbLogc</a>, <a class="link" href="lsn.html" title="Chapter 8. The DbLsn Handle">DbLsn</a> </p> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="idp2962816"></a>See Also</h3> </div> </div> </div> <p> <a class="xref" href="lsn.html#loglist" title="Logging Subsystem and Related Methods">Logging Subsystem 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="logcursor.html">Prev</a> </td> <td width="20%" align="center"> <a accesskey="u" href="lsn.html">Up</a> </td> <td width="40%" align="right"> <a accesskey="n" href="logflush.html">Next</a></td> </tr> <tr> <td width="40%" align="left" valign="top">DbEnv::log_cursor() </td> <td width="20%" align="center"> <a accesskey="h" href="index.html">Home</a> </td> <td width="40%" align="right" valign="top"> DbEnv::log_flush()</td> </tr> </table> </div> </body> </html>