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<h2 class="title" style="clear: both"><a id="mempset_clear_len"></a>DbMpoolFile::set_clear_len()</h2>
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<pre class="programlisting">#include <db_cxx.h>
int DbMpoolFile::set_clear_len(u_int32_t len); </pre>
<p>
The <code class="methodname">DbMpoolFile::set_clear_len()</code> method sets the number of initial
bytes in a page that should be set to nul when the page is created as
a result of the
<a class="link" href="mempfget.html#mpoolfget_DB_MPOOL_CREATE">DB_MPOOL_CREATE</a>
or <a class="link" href="mempfget.html#mpoolfget_DB_MPOOL_NEW">DB_MPOOL_NEW</a>
flags specified to <a class="xref" href="mempfget.html" title="DbMpoolFile::get()">DbMpoolFile::get()</a>. If no
clear length is specified, the entire page is cleared when it is
created.
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<p>
The <code class="methodname">DbMpoolFile::set_clear_len()</code> method configures a file in the
cache, not only operations performed using the specified
<a class="link" href="memp.html" title="Chapter 9. The DbMpoolFile Handle">DbMpoolFile</a> handle.
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The <code class="methodname">DbMpoolFile::set_clear_len()</code> method may not be called after the
<a class="xref" href="mempfopen.html" title="DbMpoolFile::open()">DbMpoolFile::open()</a>
method is called. If the file is already open in the cache when
<a class="xref" href="mempfopen.html" title="DbMpoolFile::open()">DbMpoolFile::open()</a> is
called, the information specified to <code class="methodname">DbMpoolFile::set_clear_len()</code>
must be consistent with the existing file or an error will be returned.
</p>
<p>
The <code class="methodname">DbMpoolFile::set_clear_len()</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.
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<h3 class="title"><a id="idp9028464"></a>Parameters</h3>
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<h4 class="title"><a id="idp9027816"></a>len</h4>
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<p>
The <span class="bold"><strong>len</strong></span> parameter is the number of
initial bytes in a page that should be set to nul when the page is
created. A value of 0 results in the entire page being set to nul
bytes.
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<p>
<a class="link" href="env.html" title="Chapter 5. The DbEnv Handle">DbEnv</a>, <a class="link" href="memp.html" title="Chapter 9. The DbMpoolFile Handle">DbMpoolFile</a>
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<a class="xref" href="memp.html#memplist" title="Memory Pools and Related Methods">Memory Pools and Related Methods</a>
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