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136 lines
4.9 KiB
HTML
136 lines
4.9 KiB
HTML
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
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<title>DB->fd()</title>
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<link rel="stylesheet" href="apiReference.css" type="text/css" />
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<meta name="generator" content="DocBook XSL Stylesheets V1.73.2" />
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<link rel="start" href="index.html" title="Berkeley DB C API Reference" />
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<link rel="up" href="db.html" title="Chapter 2. The DB Handle" />
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<link rel="prev" href="dbexists.html" title="DB->exists()" />
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<link rel="next" href="dbget.html" title="DB->get()" />
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</head>
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<body>
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<div xmlns="" class="navheader">
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<div class="libver">
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<p>Library Version 11.2.5.2</p>
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</div>
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<table width="100%" summary="Navigation header">
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<tr>
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<th colspan="3" align="center">DB->fd()</th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="dbexists.html">Prev</a> </td>
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<th width="60%" align="center">Chapter 2.
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The DB Handle
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</th>
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<td width="20%" align="right"> <a accesskey="n" href="dbget.html">Next</a></td>
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</tr>
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</table>
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<hr />
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</div>
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<div class="sect1" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h2 class="title" style="clear: both"><a id="dbfd"></a>DB->fd()</h2>
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</div>
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</div>
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</div>
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<pre class="programlisting">#include <db.h>
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int
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DB->fd(DB *db, int *fdp); </pre>
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<p>
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The <code class="methodname">DB->fd()</code> method provides access to a file descriptor
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representative of the underlying database. A file descriptor
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referring to the same file will be returned to all processes that call
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<a class="xref" href="dbopen.html" title="DB->open()">DB->open()</a> with the same
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<span class="bold"><strong>file</strong></span> parameter.
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</p>
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<p>
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This file descriptor may be safely used as a parameter to the
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<span class="bold"><strong>fcntl</strong></span>(2) and <span class="bold"><strong>flock</strong></span>(2) locking functions.
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</p>
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<p>
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The <code class="methodname">DB->fd()</code> method only supports a coarse-grained form of locking.
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Applications should instead use the Berkeley DB lock manager where
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possible.
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</p>
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<p>
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The <code class="methodname">DB->fd()</code> <span>
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<span>
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method returns a non-zero error value on failure and 0 on success.
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</span>
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</span>
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</p>
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<div class="sect2" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h3 class="title"><a id="id3676091"></a>Parameters</h3>
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</div>
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</div>
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</div>
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<div class="sect3" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h4 class="title"><a id="id3676074"></a>fdp</h4>
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</div>
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</div>
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</div>
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<p>
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The <span class="bold"><strong>fdp</strong></span> parameter references memory
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into which the current file descriptor is copied.
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</p>
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</div>
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</div>
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<div class="sect2" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h3 class="title"><a id="id3675231"></a>Class</h3>
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</div>
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</div>
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</div>
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<p>
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<a class="link" href="db.html" title="Chapter 2. The DB Handle">DB</a>
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</p>
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</div>
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<div class="sect2" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h3 class="title"><a id="id3674850"></a>See Also</h3>
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</div>
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</div>
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</div>
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<p>
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<a class="xref" href="db.html#dblist" title="Database and Related Methods">Database and Related Methods</a>
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</p>
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</div>
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</div>
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<div class="navfooter">
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<hr />
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<table width="100%" summary="Navigation footer">
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<tr>
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<td width="40%" align="left"><a accesskey="p" href="dbexists.html">Prev</a> </td>
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<td width="20%" align="center">
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<a accesskey="u" href="db.html">Up</a>
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</td>
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<td width="40%" align="right"> <a accesskey="n" href="dbget.html">Next</a></td>
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</tr>
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<tr>
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<td width="40%" align="left" valign="top">DB->exists() </td>
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<td width="20%" align="center">
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<a accesskey="h" href="index.html">Home</a>
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</td>
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<td width="40%" align="right" valign="top"> DB->get()</td>
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</tr>
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</table>
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</div>
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</body>
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</html>
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