libdb/docs/api_reference/C/logfile.html
2011-12-19 19:07:10 -05:00

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<title>DB_ENV-&gt;log_file()</title>
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<p>Library Version 11.2.5.2</p>
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<th colspan="3" align="center">DB_ENV-&gt;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 7. 
The DB_LSN Handle
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<div class="sect1" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h2 class="title" style="clear: both"><a id="logfile"></a>DB_ENV-&gt;log_file()</h2>
</div>
</div>
</div>
<pre class="programlisting">#include &lt;db.h&gt;
int
DB_ENV-&gt;log_file(DB_ENV *env,
const DB_LSN *lsn, char *namep, size_t len); </pre>
<p>
The <code class="methodname">DB_ENV-&gt;log_file()</code> method maps
<code class="classname">DB_LSN</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">DB_LSN</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 7.  The DB_LSN Handle">DB_LSN</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 7.  The DB_LSN Handle">DB_LSN</a> entries before the
earliest one needed for restart.
</p>
<p>
The <code class="methodname">DB_ENV-&gt;log_file()</code> <span>
<span>
method returns a non-zero error value on failure and 0 on success.
</span>
</span>
</p>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="id3727570"></a>Parameters</h3>
</div>
</div>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="id3727772"></a>lsn</h4>
</div>
</div>
</div>
<p>
The <span class="bold"><strong>lsn</strong></span> parameter is the
<code class="classname">DB_LSN</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="id3727620"></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="id3727799"></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">DB_ENV-&gt;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="id3727869"></a>Errors</h3>
</div>
</div>
</div>
<p>
The <code class="methodname">DB_ENV-&gt;log_file()</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="id3727949"></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="id3727769"></a>Class</h3>
</div>
</div>
</div>
<p>
<a class="link" href="env.html" title="Chapter 5.  The DB_ENV Handle">DB_ENV</a>,
<a class="link" href="logc.html" title="The DB_LOGC Handle">DB_LOGC</a>,
<a class="link" href="lsn.html" title="Chapter 7.  The DB_LSN Handle">DB_LSN</a>
</p>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="id3727970"></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>
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