mirror of
https://github.com/yasuhirokimura/db18
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Yasuhiro KIMURA
234 lines
8.2 KiB
HTML
234 lines
8.2 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>Chapter 17. Programmer Notes</title>
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<link rel="stylesheet" href="gettingStarted.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 Programmer's Reference Guide" />
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<link rel="up" href="index.html" title="Berkeley DB Programmer's Reference Guide" />
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<link rel="prev" href="apprec_config.html" title="Application configuration" />
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<link rel="next" href="program_errorret.html" title="Error returns to applications" />
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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 18.1.32</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">Chapter 17. Programmer Notes </th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="apprec_config.html">Prev</a> </td>
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<th width="60%" align="center"> </th>
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<td width="20%" align="right"> <a accesskey="n" href="program_errorret.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="chapter" 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"><a id="program"></a>Chapter 17. Programmer Notes </h2>
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</div>
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</div>
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</div>
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<div class="toc">
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<p>
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<b>Table of Contents</b>
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</p>
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<dl>
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<dt>
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<span class="sect1">
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<a href="program.html#program_appsignals">Signal handling</a>
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</span>
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</dt>
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<dt>
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<span class="sect1">
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<a href="program_errorret.html">Error returns to
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applications</a>
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</span>
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</dt>
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<dt>
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<span class="sect1">
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<a href="program_i18n.html">Globalization Support</a>
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</span>
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</dt>
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<dd>
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<dl>
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<dt>
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<span class="sect2">
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<a href="program_i18n.html#idm140088464929792">Message Format</a>
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</span>
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</dt>
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<dt>
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<span class="sect2">
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<a href="program_i18n.html#idm140088464900656">Enable Globalization Support</a>
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</span>
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</dt>
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<dt>
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<span class="sect2">
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<a href="program_i18n.html#localization_example">Localization Example</a>
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</span>
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</dt>
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</dl>
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</dd>
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<dt>
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<span class="sect1">
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<a href="program_environ.html">Environment variables</a>
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</span>
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</dt>
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<dt>
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<span class="sect1">
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<a href="program_mt.html">Multithreaded applications</a>
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</span>
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</dt>
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<dt>
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<span class="sect1">
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<a href="program_scope.html">Berkeley DB handles</a>
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</span>
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</dt>
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<dt>
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<span class="sect1">
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<a href="program_namespace.html">Name spaces</a>
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</span>
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</dt>
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<dd>
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<dl>
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<dt>
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<span class="sect2">
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<a href="program_namespace.html#idm140088464810960">C Language Name
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Space</a>
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</span>
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</dt>
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<dt>
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<span class="sect2">
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<a href="program_namespace.html#idm140088464863584">Filesystem Name Space</a>
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</span>
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</dt>
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</dl>
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</dd>
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<dt>
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<span class="sect1">
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<a href="program_ram.html">Memory-only or Flash
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configurations</a>
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</span>
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</dt>
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<dt>
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<span class="sect1">
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<a href="program_cache.html">Disk drive caches</a>
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</span>
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</dt>
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<dt>
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<span class="sect1">
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<a href="program_copy.html">Copying or moving databases</a>
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</span>
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</dt>
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<dt>
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<span class="sect1">
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<a href="program_compatible.html">Compatibility with historic UNIX interfaces</a>
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</span>
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</dt>
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<dt>
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<span class="sect1">
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<a href="program_runtime.html">Run-time configuration</a>
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</span>
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</dt>
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<dt>
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<span class="sect1">
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<a href="program_perfmon.html">Performance Event
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Monitoring</a>
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</span>
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</dt>
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<dd>
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<dl>
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<dt>
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<span class="sect2">
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<a href="program_perfmon.html#program_perfmon_dtrace">Using the DTrace Provider</a>
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</span>
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</dt>
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<dt>
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<span class="sect2">
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<a href="program_perfmon.html#program_perfmon_stap">Using SystemTap</a>
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</span>
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</dt>
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<dt>
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<span class="sect2">
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<a href="program_perfmon.html#program_perfmon_examples">Example
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Scripts</a>
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</span>
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</dt>
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<dt>
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<span class="sect2">
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<a href="program_perfmon.html#program_perfmon_probes">Performance Events Reference</a>
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</span>
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</dt>
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</dl>
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</dd>
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<dt>
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<span class="sect1">
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<a href="program_faq.html">Programmer notes FAQ</a>
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</span>
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</dt>
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</dl>
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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="program_appsignals"></a>Signal handling</h2>
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</div>
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</div>
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</div>
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<p>
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When applications using Berkeley DB receive signals, it is
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important that they exit gracefully, discarding any Berkeley
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DB locks that they may hold. This is normally done by setting
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a flag when a signal arrives and then checking for that flag
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periodically within the application. Because Berkeley DB is
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not re-entrant, the signal handler should not attempt to
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release locks and/or close the database handles itself.
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Re-entering Berkeley DB is not guaranteed to work correctly,
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and the results are undefined.
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</p>
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<p>
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If an application exits holding a lock, the situation is no
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different than if the application crashed, and all
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applications participating in the database environment must be
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shut down, and then recovery must be performed. If this is not
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done, databases may be left in an inconsistent state, or locks
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the application held may cause unresolvable deadlocks inside
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the environment, causing applications to hang.
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</p>
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<p>
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Berkeley DB restarts all system calls interrupted by
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signals, that is, any underlying system calls that return
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failure with errno set to EINTR will be restarted rather than
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failing.
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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="apprec_config.html">Prev</a> </td>
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<td width="20%" align="center"> </td>
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<td width="40%" align="right"> <a accesskey="n" href="program_errorret.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">Application configuration </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"> Error returns to
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applications</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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