<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"
lang="en" dir="ltr">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>
volatile [C++ Reference]
</title>
<meta name="generator" content="DokuWiki Release 2009-12-25c &quot;Lemming&quot;" />
<meta name="robots" content="index,follow" />
<meta name="date" content="2008-10-14T15:42:05-0700" />
<meta name="keywords" content="keywords,volatile" />
<link rel="search" type="application/opensearchdescription+xml" href="/wiki/lib/exe/opensearch.php" title="C++ Reference" />
<link rel="start" href="/wiki/" />
<link rel="contents" href="/wiki/keywords/volatile?do=index" title="Index" />
<link rel="alternate" type="application/rss+xml" title="Recent Changes" href="/wiki/feed.php" />
<link rel="alternate" type="application/rss+xml" title="Current Namespace" href="/wiki/feed.php?mode=list&amp;ns=keywords" />
<link rel="edit" title="Edit this page" href="/wiki/keywords/volatile?do=edit" />
<link rel="alternate" type="text/html" title="Plain HTML" href="/wiki/_export/xhtml/keywords/volatile" />
<link rel="alternate" type="text/plain" title="Wiki Markup" href="/wiki/_export/raw/keywords/volatile" />
<link rel="stylesheet" media="all" type="text/css" href="/wiki/lib/exe/css.php?s=all&amp;t=custom1&amp;tseed=1272971091" />
<link rel="stylesheet" media="screen" type="text/css" href="/wiki/lib/exe/css.php?t=custom1&amp;tseed=1272971091" />
<link rel="stylesheet" media="print" type="text/css" href="/wiki/lib/exe/css.php?s=print&amp;t=custom1&amp;tseed=1272971091" />
<script type="text/javascript" charset="utf-8" ><!--//--><![CDATA[//><!--
var NS='keywords';var JSINFO = {"id":"keywords:volatile","namespace":"keywords"};
//--><!]]></script>
<script type="text/javascript" charset="utf-8" src="/wiki/lib/exe/js.php?tseed=1272971091" ></script>
<link rel="shortcut icon" href="/wiki/lib/tpl/custom1/images/favicon.png" />
</head>
<body>
<div class="dokuwiki">
<div class="stylehead">
<div class="header">
<div class="pagename">
[[<a href="../keywords/volatile.html" title="Backlinks">volatile</a>]]
</div>
<div class="logo">
<a href="http://www.cppreference.com" name="dokuwiki__top" id="dokuwiki__top" accesskey="h" title="[ALT+H]">C++ Reference</a> </div>
<div class="clearer"></div>
</div>
<div class="breadcrumbs">
<span class="bchead">You are here: </span><a href="../start.html" title="start">C++ Reference</a> &raquo; <a href="../keywords/start.html" title="keywords:start">C++ Keywords</a> &raquo; <a href="../keywords/volatile.html" title="keywords:volatile">volatile</a> </div>
</div>
<div class="plugin_translation"><span>Translations of this page<sup><a href="../localization.html" class="wikilink1" title="localization">?</a></sup>:</span> <ul> <li><div class="li"><span class="curid"><a href="../keywords/volatile.html" class="wikilink1" title="keywords:volatile">en</a></span></div></li> <li><div class="li"><a href="../br-pt/keywords/volatile.html" class="wikilink2" title="br-pt:keywords:volatile" rel="nofollow">br-pt</a></div></li> <li><div class="li"><a href="../cn/keywords/volatile.html" class="wikilink2" title="cn:keywords:volatile" rel="nofollow">cn</a></div></li> <li><div class="li"><a href="../cz/keywords/volatile.html" class="wikilink2" title="cz:keywords:volatile" rel="nofollow">cz</a></div></li> <li><div class="li"><a href="../de/keywords/volatile.html" class="wikilink2" title="de:keywords:volatile" rel="nofollow">de</a></div></li> <li><div class="li"><a href="../es/keywords/volatile.html" class="wikilink2" title="es:keywords:volatile" rel="nofollow">es</a></div></li> <li><div class="li"><a href="../fr/keywords/volatile.html" class="wikilink2" title="fr:keywords:volatile" rel="nofollow">fr</a></div></li> <li><div class="li"><a href="../it/keywords/volatile.html" class="wikilink2" title="it:keywords:volatile" rel="nofollow">it</a></div></li> <li><div class="li"><a href="../jp/keywords/volatile.html" class="wikilink1" title="jp:keywords:volatile">jp</a></div></li> <li><div class="li"><a href="../nl/keywords/volatile.html" class="wikilink2" title="nl:keywords:volatile" rel="nofollow">nl</a></div></li> <li><div class="li"><a href="../pl/keywords/volatile.html" class="wikilink2" title="pl:keywords:volatile" rel="nofollow">pl</a></div></li> <li><div class="li"><a href="../ro/keywords/volatile.html" class="wikilink2" title="ro:keywords:volatile" rel="nofollow">ro</a></div></li> <li><div class="li"><a href="../ru/keywords/volatile.html" class="wikilink2" title="ru:keywords:volatile" rel="nofollow">ru</a></div></li> <li><div class="li"><a href="../sk/keywords/volatile.html" class="wikilink2" title="sk:keywords:volatile" rel="nofollow">sk</a></div></li> <li><div class="li"><a href="../tr/keywords/volatile.html" class="wikilink2" title="tr:keywords:volatile" rel="nofollow">tr</a></div></li> <li><div class="li"><a href="../tw/keywords/volatile.html" class="wikilink2" title="tw:keywords:volatile" rel="nofollow">tw</a></div></li></ul></div>
<div class="page">
<script src="http://www.google-analytics.com/urchin.js" type="text/javascript">
</script>
<script type="text/javascript">
_uacct = "UA-2828341-1";
urchinTracker();
</script>
<!-- wikipage start -->
<h2><a name="volatile" id="volatile">volatile</a></h2>
<div class="level2">
<p>
The volatile keyword is an implementation-dependent modifier, used when
declaring variables, which prevents the compiler from optimizing those
variables. Volatile should be used with variables whose value can change in
unexpected ways (i.e. through an interrupt), which could conflict with
optimizations that the compiler might perform.
</p>
</div>
<div class="secedit"><form class="button btn_secedit" method="post" action="/wiki/keywords/volatile"><div class="no"><input type="hidden" name="do" value="edit" /><input type="hidden" name="lines" value="3-" /><input type="hidden" name="rev" value="1224024125" /><input type="submit" value="Edit" class="button" title="volatile" /></div></form></div>
<!-- wikipage stop -->
</div>
<div class="clearer">&nbsp;</div>
<div class="stylefoot">
<div class="meta">
<div class="user">
</div>
<!--
<div class="doc">
keywords/volatile.txt &middot; Last modified: 10/14/2008 15:42 (external edit) </div>
-->
</div>
<div class="bar" id="bar__bottom">
<div class="bar-left" id="bar__bottomleft">
<a href="../keywords/volatile.html" class="action edit" accesskey="e" rel="nofollow">Edit this page</a> &#149;
<a href="../keywords/volatile.html" class="action revisions" accesskey="o" rel="nofollow">Old revisions</a> </div>
<div class="bar-right" id="bar__bottomright">
&#149;
&#149;
&#149;
<a href="../keywords/volatile.html" class="action login" rel="nofollow">Login</a> &#149;
<a href="../keywords/volatile.html" class="action index" accesskey="x" rel="nofollow">Index</a> &#149;
<a href="../keywords/volatile.html" class="action recent" accesskey="r" rel="nofollow">Recent changes</a> &#149;
<a href="../feed.php.html" title="Recent changes RSS feed">RSS</a> &#149;
<a href='http://creativecommons.org/licenses/by/3.0/us/' title='Creative Commons license'>cc</a> &#149;
<form action="/wiki/" accept-charset="utf-8" class="search" id="dw__search"><div class="no"><input type="hidden" name="do" value="search" /><input type="text" id="qsearch__in" accesskey="f" name="id" class="edit" title="[ALT+F]" /><input type="submit" value="Search" class="button" title="Search" /><div id="qsearch__out" class="ajax_qsearch JSpopup"></div></div></form>&nbsp;
</div>
<div class="clearer"></div>
</div>
</div>
</div>
<div class="no"><img src="/wiki/lib/exe/indexer.php?id=keywords%3Avolatile&amp;1273193211" width="1" height="1" alt="" /></div>
</body>
</html>