<?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>DB_MPOOLFILE->set_clear_len()</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="memp.html" title="Chapter 8. The DB_MPOOLFILE Handle" /> <link rel="prev" href="mempget_priority.html" title="DB_MPOOLFILE->get_priority()" /> <link rel="next" href="mempset_fileid.html" title="DB_MPOOLFILE->set_fileid()" /> </head> <body> <div class="navheader"> <table width="100%" summary="Navigation header"> <tr> <th colspan="3" align="center">DB_MPOOLFILE->set_clear_len()</th> </tr> <tr> <td width="20%" align="left"><a accesskey="p" href="mempget_priority.html">Prev</a> </td> <th width="60%" align="center">Chapter 8. The DB_MPOOLFILE Handle </th> <td width="20%" align="right"> <a accesskey="n" href="mempset_fileid.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="mempset_clear_len"></a>DB_MPOOLFILE->set_clear_len()</h2> </div> </div> </div> <pre class="programlisting">#include <db.h> int DB_MPOOLFILE->set_clear_len(DB_MPOOLFILE *mpf, u_int32_t len); </pre> <p> The <code class="methodname">DB_MPOOLFILE->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="DB_MPOOLFILE->get()">DB_MPOOLFILE->get()</a>. If no clear length is specified, the entire page is cleared when it is created. </p> <p> The <code class="methodname">DB_MPOOLFILE->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 8. The DB_MPOOLFILE Handle">DB_MPOOLFILE</a> handle. </p> <p> The <code class="methodname">DB_MPOOLFILE->set_clear_len()</code> method may not be called after the <a class="xref" href="mempfopen.html" title="DB_MPOOLFILE->open()">DB_MPOOLFILE->open()</a> method is called. If the file is already open in the cache when <a class="xref" href="mempfopen.html" title="DB_MPOOLFILE->open()">DB_MPOOLFILE->open()</a> is called, the information specified to <code class="methodname">DB_MPOOLFILE->set_clear_len()</code> must be consistent with the existing file or an error will be returned. </p> <p> The <code class="methodname">DB_MPOOLFILE->set_clear_len()</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="id1691928"></a>Parameters</h3> </div> </div> </div> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h4 class="title"><a id="id1691852"></a>len</h4> </div> </div> </div> <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. </p> </div> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="id1691434"></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="memp.html" title="Chapter 8. The DB_MPOOLFILE Handle">DB_MPOOLFILE</a> </p> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> <h3 class="title"><a id="id1691638"></a>See Also</h3> </div> </div> </div> <p> <a class="xref" href="memp.html#memplist" title="Memory Pools and Related Methods">Memory Pools 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="mempget_priority.html">Prev</a> </td> <td width="20%" align="center"> <a accesskey="u" href="memp.html">Up</a> </td> <td width="40%" align="right"> <a accesskey="n" href="mempset_fileid.html">Next</a></td> </tr> <tr> <td width="40%" align="left" valign="top">DB_MPOOLFILE->get_priority() </td> <td width="20%" align="center"> <a accesskey="h" href="index.html">Home</a> </td> <td width="40%" align="right" valign="top"> DB_MPOOLFILE->set_fileid()</td> </tr> </table> </div> </body> </html>