1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>__init/__exit/__initdata include/linux/init.h</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"><link rel="home" href="index.html" title="Unreliable Guide To Hacking The Linux Kernel"><link rel="up" href="common-routines.html" title="Chapter&#160;6.&#160;Common Routines"><link rel="prev" href="routines-processorids.html" title="smp_processor_id() include/asm/smp.h"><link rel="next" href="routines-init-again.html" title="__initcall()/module_init() include/linux/init.h"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span class="type">__init</span>/<span class="type">__exit</span>/<span class="type">__initdata</span>
2    <code class="filename">include/linux/init.h</code></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="routines-processorids.html">Prev</a>&#160;</td><th width="60%" align="center">Chapter&#160;6.&#160;Common Routines</th><td width="20%" align="right">&#160;<a accesskey="n" href="routines-init-again.html">Next</a></td></tr></table><hr></div><div class="sect1"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="routines-init"></a><span class="type">__init</span>/<span class="type">__exit</span>/<span class="type">__initdata</span>
3    <code class="filename">include/linux/init.h</code></h2></div></div></div><p>
4    After boot, the kernel frees up a special section; functions
5    marked with <span class="type">__init</span> and data structures marked with
6    <span class="type">__initdata</span> are dropped after boot is complete: similarly
7    modules discard this memory after initialization.  <span class="type">__exit</span>
8    is used to declare a function which is only required on exit: the
9    function will be dropped if this file is not compiled as a module.
10    See the header file for use. Note that it makes no sense for a function
11    marked with <span class="type">__init</span> to be exported to modules with 
12    <code class="function">EXPORT_SYMBOL()</code> - this will break.
13   </p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="routines-processorids.html">Prev</a>&#160;</td><td width="20%" align="center"><a accesskey="u" href="common-routines.html">Up</a></td><td width="40%" align="right">&#160;<a accesskey="n" href="routines-init-again.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><code class="function">smp_processor_id</code>()
14    <code class="filename">include/asm/smp.h</code>&#160;</td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top">&#160;<code class="function">__initcall()</code>/<code class="function">module_init()</code>
15    <code class="filename">include/linux/init.h</code></td></tr></table></div></body></html>
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