1<?xml version="1.0" encoding="UTF-8" standalone="no"?> 2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3<html xmlns="http://www.w3.org/1999/xhtml"> 4 <head> 5 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> 6 <title>DbMpoolFile::get_fileid()</title> 7 <link rel="stylesheet" href="apiReference.css" type="text/css" /> 8 <meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /> 9 <link rel="start" href="index.html" title="Berkeley DB C++ API Reference" /> 10 <link rel="up" href="memp.html" title="Chapter 9. The DbMpoolFile Handle" /> 11 <link rel="prev" href="mempget_clear_len.html" title="DbMpoolFile::get_clear_len()" /> 12 <link rel="next" href="mempget_flags.html" title="DbMpoolFile::get_flags()" /> 13 </head> 14 <body> 15 <div class="navheader"> 16 <table width="100%" summary="Navigation header"> 17 <tr> 18 <th colspan="3" align="center">DbMpoolFile::get_fileid()</th> 19 </tr> 20 <tr> 21 <td width="20%" align="left"><a accesskey="p" href="mempget_clear_len.html">Prev</a> </td> 22 <th width="60%" align="center">Chapter 9. 23 The DbMpoolFile Handle 24 </th> 25 <td width="20%" align="right"> <a accesskey="n" href="mempget_flags.html">Next</a></td> 26 </tr> 27 </table> 28 <hr /> 29 </div> 30 <div class="sect1" lang="en" xml:lang="en"> 31 <div class="titlepage"> 32 <div> 33 <div> 34 <h2 class="title" style="clear: both"><a id="mempget_fileid"></a>DbMpoolFile::get_fileid()</h2> 35 </div> 36 </div> 37 </div> 38 <pre class="programlisting">#include <db_cxx.h> 39 40int DbMpoolFile::get_fileid(u_int8_t *fileid);</pre> 41 <p> 42 The <code class="methodname">DbMpoolFile::get_fileid()</code> method copies the 43 file's identifier into the memory location referenced by <span class="bold"><strong>fileid</strong></span>. The fileid specifies a unique 44 identifier for the file, which is used so that the cache functions 45 (that is, the shared memory buffer pool functions) are able to 46 uniquely identify files. This is necessary for multiple processes 47 wanting to share a file to correctly identify the file in the 48 cache. 49 </p> 50 <p> 51 The <code class="methodname">DbMpoolFile::get_fileid()</code> <span> 52 53 <span> 54 method either returns a non-zero error value or throws an 55 exception that encapsulates a non-zero error value on 56 failure, and returns 0 on success. 57 </span> 58 </span> 59 </p> 60 <div class="sect2" lang="en" xml:lang="en"> 61 <div class="titlepage"> 62 <div> 63 <div> 64 <h3 class="title"><a id="id1695593"></a>Class</h3> 65 </div> 66 </div> 67 </div> 68 <p> 69 <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> 70 </p> 71 </div> 72 <div class="sect2" lang="en" xml:lang="en"> 73 <div class="titlepage"> 74 <div> 75 <div> 76 <h3 class="title"><a id="id1695641"></a>See Also</h3> 77 </div> 78 </div> 79 </div> 80 <p> 81 <a class="xref" href="memp.html#memplist" title="Memory Pools and Related Methods">Memory Pools and Related Methods</a>, 82 <a class="xref" href="mempset_fileid.html" title="DbMpoolFile::set_fileid()">DbMpoolFile::set_fileid()</a> 83 </p> 84 </div> 85 </div> 86 <div class="navfooter"> 87 <hr /> 88 <table width="100%" summary="Navigation footer"> 89 <tr> 90 <td width="40%" align="left"><a accesskey="p" href="mempget_clear_len.html">Prev</a> </td> 91 <td width="20%" align="center"> 92 <a accesskey="u" href="memp.html">Up</a> 93 </td> 94 <td width="40%" align="right"> <a accesskey="n" href="mempget_flags.html">Next</a></td> 95 </tr> 96 <tr> 97 <td width="40%" align="left" valign="top">DbMpoolFile::get_clear_len() </td> 98 <td width="20%" align="center"> 99 <a accesskey="h" href="index.html">Home</a> 100 </td> 101 <td width="40%" align="right" valign="top"> DbMpoolFile::get_flags()</td> 102 </tr> 103 </table> 104 </div> 105 </body> 106</html> 107