<?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_env_set_func_file_map</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="setfunc.html" title="Appendix 3. Berkeley DB Application Space Static Functions" />
<link rel="prev" href="db_env_set_func_exists.html" title="db_env_set_func_exists" />
<link rel="next" href="db_env_set_func_free.html" title="db_env_set_func_free" />
</head>
<body>
<div class="navheader">
<table width="100%" summary="Navigation header">
<tr>
<th colspan="3" align="center">db_env_set_func_file_map</th>
</tr>
<tr>
<td width="20%" align="left"><a accesskey="p" href="db_env_set_func_exists.html">Prev</a> </td>
<th width="60%" align="center">Appendix 3.
Berkeley DB Application Space Static Functions
</th>
<td width="20%" align="right"> <a accesskey="n" href="db_env_set_func_free.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="db_env_set_func_file_map"></a>db_env_set_func_file_map</h2>
</div>
</div>
</div>
<pre class="programlisting">#include <db.h>
int
db_env_set_func_file_map(int (*func_file_map)(DB_ENV *dbenv, char *path,
size_t len, int is_rdonly, void **addr),
int (*func_file_unmap)(DB_ENV *dbenv, void *addr)); </pre>
<p>
The Berkeley DB library optionally uses the ability to map a file into
memory.
</p>
<p>
The <code class="function">db_env_set_func_file_map()</code> function configures all operations
performed by a process and all of its threads of control, not
operations confined to a single database environment.
</p>
<p>
Although the <code class="function">db_env_set_func_file_map()</code> function may be called at any time
during the life of the application, it should normally be called
before making calls to the <a class="xref" href="envcreate.html" title="db_env_create">db_env_create</a> or
<a class="xref" href="dbcreate.html" title="db_create">db_create</a> methods.
</p>
<p>
The <code class="function">db_env_set_func_file_map()</code> <span>
function returns a non-zero error value on failure and 0 on success.
</span>
</p>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="id1718906"></a>Parameters</h3>
</div>
</div>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="id1718693"></a>func_file_map</h4>
</div>
</div>
</div>
<p>
The <span class="bold"><strong>func_file_map</strong></span> parameter is the
function which maps a file into memory. The function takes 5
parameters:
</p>
<div class="itemizedlist">
<ul type="disc">
<li>
<p>
<span class="bold"><strong>dbenv</strong></span>
</p>
<p>
The <span class="bold"><strong>dbenv</strong></span> parameter is the enclosing
database environment handle.
</p>
</li>
<li>
<p>
<span class="bold"><strong>path</strong></span>
</p>
<p>
The <span class="bold"><strong>path</strong></span> parameter is the name of
file. Repeated requests for the mapping of the same name should
return a reference to the same memory.
</p>
</li>
<li>
<p>
<span class="bold"><strong>len</strong></span>
</p>
<p>
The <span class="bold"><strong>len</strong></span> parameter is the length, in
bytes, of the file.
</p>
</li>
<li>
<p>
<span class="bold"><strong>is_rdonly</strong></span>
</p>
<p>
The <span class="bold"><strong>is_rdonly</strong></span> parameter will be
non-zero if the mapped file is read-only.
</p>
</li>
<li>
<p>
<span class="bold"><strong>addr</strong></span>
</p>
<p>
The <span class="bold"><strong>addr</strong></span> parameter is the memory
location into which a pointer to the mapped file is returned.
</p>
</li>
</ul>
</div>
<p>
The <span class="bold"><strong>func_file_map</strong></span> function must
return the value of <span class="bold"><strong>errno</strong></span> on failure
and 0 on success.
</p>
</div>
<div class="sect3" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h4 class="title"><a id="id1719225"></a>func_file_unmap</h4>
</div>
</div>
</div>
<p>
The <span class="bold"><strong>func_file_unmap</strong></span> parameter is the
function which unmaps a file from memory. The function takes 2
parameters:
</p>
<div class="itemizedlist">
<ul type="disc">
<li>
<p>
<span class="bold"><strong>dbenv</strong></span>
</p>
<p>
The <span class="bold"><strong>dbenv</strong></span> parameter is the enclosing
database environment handle.
</p>
</li>
<li>
<p>
<code class="literal">addr</code>
</p>
<p>
The <span class="bold"><strong>addr</strong></span> parameter is the value
returned by the <span class="bold"><strong>func_file_map</strong></span>
function when the file or region was mapped into memory.
</p>
</li>
</ul>
</div>
</div>
</div>
<div class="sect2" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="id1719295"></a>See Also</h3>
</div>
</div>
</div>
<p>
<a href="../../programmer_reference/program_runtime.html" class="olink">Run-time configuration</a>
</p>
</div>
</div>
<div class="navfooter">
<hr />
<table width="100%" summary="Navigation footer">
<tr>
<td width="40%" align="left"><a accesskey="p" href="db_env_set_func_exists.html">Prev</a> </td>
<td width="20%" align="center">
<a accesskey="u" href="setfunc.html">Up</a>
</td>
<td width="40%" align="right"> <a accesskey="n" href="db_env_set_func_free.html">Next</a></td>
</tr>
<tr>
<td width="40%" align="left" valign="top">db_env_set_func_exists </td>
<td width="20%" align="center">
<a accesskey="h" href="index.html">Home</a>
</td>
<td width="40%" align="right" valign="top"> db_env_set_func_free</td>
</tr>
</table>
</div>
</body>
</html>
distrib
>
Mandriva
>
2010.1
>
x86_64
>
media
>
main-release
>
by-pkgid
>
a00abf5f94bf470fd4cc9e10b2d135e0
>
files
>
45
