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13<b>DbMpoolFile::set_clear_len</b>
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21<b><pre>
22#include &lt;db_cxx.h&gt;
23<p>
24int
25DbMpoolFile::set(u_int32_t len);
26<p>
27int
28DbMpoolFile::get_clear_len(u_int32_t *lenp);
29</pre></b>
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31<b>Description: DbMpoolFile::set_clear_len</b>
32<p>The DbMpoolFile::set_clear_len method sets the number of initial bytes in a
33page that should be set to nul when the page is created as a result of
34the <a href="../api_cxx/memp_fget.html#DB_MPOOL_CREATE">DB_MPOOL_CREATE</a> or <a href="../api_cxx/memp_fget.html#DB_MPOOL_NEW">DB_MPOOL_NEW</a> flags being
35specified to <a href="../api_cxx/memp_fget.html">DbMpoolFile::get</a>.  If no clear length is specified, the
36entire page is cleared when it is created.</p>
37<p>The DbMpoolFile::set_clear_len method configures a file in the memory pool, not only
38operations performed using the specified <a href="../api_cxx/mempfile_class.html">DbMpoolFile</a> handle.</p>
39<p>The DbMpoolFile::set_clear_len method may not be called after the <a href="../api_cxx/memp_fopen.html">DbMpoolFile::open</a> method is
40called.
41If the file is already open in the memory pool when
42<a href="../api_cxx/memp_fopen.html">DbMpoolFile::open</a> is called, the information specified to DbMpoolFile::set_clear_len
43must be consistent with the existing file or an error will be
44returned.
45</p>
46<p>The DbMpoolFile::set_clear_len method
47either returns a non-zero error value
48or throws an exception that encapsulates a non-zero error value on
49failure, and returns 0 on success.
50</p>
51<b>Parameters</b> <br>
52 <b>len</b><ul compact><li>The <b>len</b> parameter is the number of initial bytes in a page that
53should be set to nul when the page is created.  A value of 0 results in
54the entire page being set to nul bytes.</ul>
55<br>
56<hr size=1 noshade>
57<b>Description: DbMpoolFile::get_clear_len</b>
58<p>The DbMpoolFile::get_clear_len method returns the bytes to be cleared.</p>
59<p>The DbMpoolFile::get_clear_len method may be called at any time during the life of the
60application.</p>
61<p>The DbMpoolFile::get_clear_len method
62either returns a non-zero error value
63or throws an exception that encapsulates a non-zero error value on
64failure, and returns 0 on success.
65</p>
66<b>Parameters</b> <br>
67 <b>lenp</b><ul compact><li>The DbMpoolFile::get_clear_len method returns  the
68bytes to be cleared in <b>lenp</b>.</ul>
69<br>
70<hr size=1 noshade>
71<br><b>Class</b>
72<a href="../api_cxx/env_class.html">DbEnv</a>, <a href="../api_cxx/mempfile_class.html">DbMpoolFile</a>
73<br><b>See Also</b>
74<a href="../api_cxx/memp_list.html">Memory Pools and Related Methods</a>
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