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Release 5.2.28 on 6/10/2011
2011-09-13 17:44:24 +00:00
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<p>Library Version 11.2.5.2</p>
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<th colspan="3" align="center">DbLogc::get()</th>
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<tr>
<td width="20%" align="left"><a accesskey="p" href="logcclose.html">Prev</a> </td>
<th width="60%" align="center">Chapter 8. 
The DbLsn Handle
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<div class="sect1" lang="en" xml:lang="en">
<div class="titlepage">
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<div>
<h2 class="title" style="clear: both"><a id="logcget"></a>DbLogc::get()</h2>
</div>
</div>
</div>
<pre class="programlisting">#include &lt;db_cxx.h&gt;
int
DbLogc::get(DbLsn *lsn, Dbt *data, u_int32_t flags);</pre>
<p>
The <code class="methodname">DbLogc::get()</code> method returns records from the log.
</p>
<p>
Unless otherwise specified, the <code class="methodname">DbLogc::get()</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>
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<h3 class="title"><a id="id3622771"></a>Parameters</h3>
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</div>
</div>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
Release 5.2.36 on 9/14/2022
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<h4 class="title"><a id="id3622760"></a>lsn</h4>
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</div>
</div>
</div>
<p>
When the <span class="bold"><strong>flag</strong></span> parameter is set to
DB_CURRENT, DB_FIRST, DB_LAST, DB_NEXT or DB_PREV, the <span class="bold"><strong>lsn</strong></span> parameter is overwritten with the
<a class="link" href="lsn.html" title="Chapter 8.  The DbLsn Handle">DbLsn</a> value of the record
retrieved. When <span class="bold"><strong>flag</strong></span> is set to
DB_SET, the <span class="bold"><strong>lsn</strong></span> parameter is the
<a class="link" href="lsn.html" title="Chapter 8.  The DbLsn Handle">DbLsn</a> value of the
record to be retrieved.
</p>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
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<h4 class="title"><a id="id3622838"></a>data</h4>
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</div>
</div>
</div>
<p>
The data field of the <span class="bold"><strong>data</strong></span> structure
is set to the record retrieved, and the size field indicates the
number of bytes in the record. See
<a class="link" href="dbt.html" title="Chapter 4.  The Dbt Handle">Dbt</a> for a description of other
fields in the <span class="bold"><strong>data</strong></span> structure. The
<a class="link" href="dbt.html#dbt_DB_DBT_MALLOC">DB_DBT_MALLOC</a>,
<a class="link" href="dbt.html#dbt_DB_DBT_REALLOC">DB_DBT_REALLOC</a>
and <a class="link" href="dbt.html#dbt_DB_DBT_USERMEM">DB_DBT_USERMEM</a>
flags may be specified for any
<a class="link" href="dbt.html" title="Chapter 4.  The Dbt Handle">Dbt</a> used for data retrieval.
</p>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
Release 5.2.36 on 9/14/2022
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<h4 class="title"><a id="id3622617"></a>flags</h4>
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</div>
</div>
</div>
<p>
The <span class="bold"><strong>flags</strong></span> parameter must be set to
one of the following values:
</p>
<div class="itemizedlist">
<ul type="disc">
<li>
<p><a id="get_DB_CURRENT"></a>
<code class="literal">DB_CURRENT</code>
</p>
<p>
Return the log record to which the log currently refers.
</p>
</li>
<li>
<p><a id="get_DB_FIRST"></a>
<code class="literal">DB_FIRST</code>
</p>
<p>
The first record from any of the log files found in the log directory
is returned in the <span class="bold"><strong>data</strong></span> parameter.
The <span class="bold"><strong>lsn</strong></span> parameter is overwritten with
the <a class="link" href="lsn.html" title="Chapter 8.  The DbLsn Handle">DbLsn</a> of the record
returned.
</p>
<p>
The <code class="methodname">DbLogc::get()</code> method will return <a href="../../programmer_reference/program_errorret.html#program_errorret.DB_NOTFOUND" class="olink">DB_NOTFOUND</a> if
DB_FIRST is set and the log is empty.
</p>
</li>
<li>
<p><a id="get_DB_LAST"></a>
<code class="literal">DB_LAST</code>
</p>
<p>
The last record in the log is returned in the <span class="bold"><strong>data</strong></span> parameter. The <span class="bold"><strong>lsn</strong></span> parameter is overwritten with the
<a class="link" href="lsn.html" title="Chapter 8.  The DbLsn Handle">DbLsn</a> of the record returned.
</p>
<p>
The <code class="methodname">DbLogc::get()</code> method will return <a href="../../programmer_reference/program_errorret.html#program_errorret.DB_NOTFOUND" class="olink">DB_NOTFOUND</a> if
DB_LAST is set and the log is empty.
</p>
</li>
<li>
<p><a id="get_DB_NEXT"></a>
<code class="literal">DB_NEXT</code>
</p>
<p>
The current log position is advanced to the next record in the log,
and that record is returned in the <span class="bold"><strong>data</strong></span> parameter. The <span class="bold"><strong>lsn</strong></span> parameter is overwritten with the
<a class="link" href="lsn.html" title="Chapter 8.  The DbLsn Handle">DbLsn</a> of the record returned.
</p>
<p>
If the cursor has not been initialized via DB_FIRST, DB_LAST, DB_SET,
DB_NEXT, or DB_PREV, <code class="methodname">DbLogc::get()</code> will return the first record in
the log.
</p>
<p>
The <code class="methodname">DbLogc::get()</code> method will return <a href="../../programmer_reference/program_errorret.html#program_errorret.DB_NOTFOUND" class="olink">DB_NOTFOUND</a> if
DB_NEXT is set and the last log record has already been returned or
the log is empty.
</p>
</li>
<li>
<p><a id="get_DB_PREV"></a>
<code class="literal">DB_PREV</code>
</p>
<p>
The current log position is advanced to the previous record in the
log, and that record is returned in the <span class="bold"><strong>data</strong></span> parameter. The <span class="bold"><strong>lsn</strong></span> parameter is overwritten with the
<a class="link" href="lsn.html" title="Chapter 8.  The DbLsn Handle">DbLsn</a> of the record returned.
</p>
<p>
If the cursor has not been initialized via DB_FIRST, DB_LAST, DB_SET,
DB_NEXT, or DB_PREV, <code class="methodname">DbLogc::get()</code> will return the last record in
the log.
</p>
<p>
The <code class="methodname">DbLogc::get()</code> method will return <a href="../../programmer_reference/program_errorret.html#program_errorret.DB_NOTFOUND" class="olink">DB_NOTFOUND</a> if
DB_PREV is set and the first log record has already been returned or
the log is empty.
</p>
</li>
<li>
<p><a id="get_DB_SET"></a>
<code class="literal">DB_SET</code>
</p>
<p>
Retrieve the record specified by the <span class="bold"><strong>lsn</strong></span> parameter.
</p>
</li>
</ul>
</div>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
Release 5.2.36 on 9/14/2022
2011-12-20 00:07:10 +00:00
<h3 class="title"><a id="id3623063"></a>Errors</h3>
Release 5.2.28 on 6/10/2011
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</div>
</div>
</div>
<p>
The <code class="methodname">DbLogc::get()</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>
Release 5.2.36 on 9/14/2022
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<h4 class="title"><a id="id3623137"></a>EINVAL</h4>
Release 5.2.28 on 6/10/2011
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</div>
</div>
</div>
<p>
If the DB_CURRENT flag was set and the log cursor has not yet been
initialized; the DB_CURRENT, DB_NEXT, or DB_PREV flags were set and
the log was opened with the DB_THREAD flag set; the DB_SET flag was
set and the specified log sequence number does not appear in the log;
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>
Release 5.2.36 on 9/14/2022
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<h3 class="title"><a id="id3623054"></a>Class</h3>
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</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>
Release 5.2.36 on 9/14/2022
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<h3 class="title"><a id="id3623030"></a>See Also</h3>
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</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>
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<td width="40%" align="left"><a accesskey="p" href="logcclose.html">Prev</a> </td>
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<a accesskey="u" href="lsn.html">Up</a>
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</tr>
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<td width="40%" align="left" valign="top">DbLogc::close() </td>
<td width="20%" align="center">
<a accesskey="h" href="index.html">Home</a>
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<td width="40%" align="right" valign="top"> DbEnv::log_compare()</td>
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