<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Language" content="en-us">
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<link href="../pool.css" rel="stylesheet" type="text/css">
<title>mutex - Mutex</title>
</head>
<body>
<img src="../../../../boost.png" width="276" height="86" alt="C++ Boost">
<h1 align="center">mutex - Mutex</h1>
<h2>Introduction</h2>
<p>detail/mutex.hpp provides several mutex types that provide a consistent
interface for OS-supplied mutex types. These are all thread-level mutexes;
interprocess mutexes are not supported.</p>
<h2>Configuration</h2>
<p>This header file will try to guess what kind of system it is on. It will
auto-configure itself for Win32 or POSIX+pthread systems. To stub out all
mutex code, bypassing the auto-configuration, <span class="code">#define
BOOST_NO_MT</span> before any inclusion of this header. To prevent ODR
violations, this should be defined in <strong>every</strong> translation
unit in your project, including any library files.</p>
<h2>Synopsis</h2>
<pre class="code">
namespace details {
namespace pool {
// Only present if on a Win32 system
class Win32_mutex
{
private:
Win32_mutex(const Win32_mutex &);
void operator=(const Win32_mutex &);
public:
Win32_mutex();
~Win32_mutex();
void lock();
void unlock();
};
// Only present if on a POSIX+pthread system
class pthread_mutex
{
private:
pthread_mutex(const pthread_mutex &);
void operator=(const pthread_mutex &);
public:
pthread_mutex();
~pthread_mutex();
void lock();
void unlock();
};
// Present on all systems
class null_mutex
{
private:
null_mutex(const null_mutex &);
void operator=(const null_mutex &);
public:
null_mutex();
~null_mutex();
static void lock();
static void unlock();
};
// This will be one of the types above
typedef ... default_mutex;
} // namespace pool
} // namespace details
</pre>
<h2>Semantics</h2>
<table border align="center" summary="">
<caption>
<em>Symbol Table</em>
</caption>
<tr>
<th>Symbol</th>
<th>Meaning</th>
</tr>
<tr>
<td class="code">Mutex</td>
<td>Any type defined in this header</td>
</tr>
<tr>
<td class="code">t</td>
<td>value of type <span class="code">Mutex</span></td>
</tr>
</table><br>
<table border align="center" summary="">
<caption>
<em>Requirements satisfied by <span class="code">mutex</span></em>
</caption>
<tr>
<th>Expression</th>
<th>Return Type</th>
<th>Assertion/Note/Pre/Post-Condition</th>
</tr>
<tr>
<td class="code">m.lock()</td>
<td>not used</td>
<td>Locks the mutex</td>
</tr>
<tr>
<td class="code">m.unlock()</td>
<td>not used</td>
<td>Unlocks the mutex</td>
</tr>
</table>
<p>Each mutex is always either owned or unowned. If owned, then it is owned
by a particular thread. To "lock" a mutex means to wait until the mutex is
unowned, and then make it owned by the current thread. To "unlock" a mutex
means to release ownership from the current thread (note that the current
thread <strong>must</strong> own the mutex to release that ownership!). As
a special case, the <span class="code">null_mutex</span> never waits.</p>
<h2>Dependencies</h2>
<p>May include the system headers <span class=
"code"><windows.h></span>, <span class=
"code"><unistd.h></span>, and/or <span class=
"code"><pthread.h></span>.</p>
<h2>Future Directions</h2>
<p>This header will eventually be replaced by a Boost multithreading
library.</p>
<hr>
<p><a href="http://validator.w3.org/check?uri=referer"><img border="0" src=
"../../../../doc/images/valid-html401.png" alt="Valid HTML 4.01 Transitional"
height="31" width="88"></a></p>
<p>Revised
<!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %B, %Y" startspan -->05
December, 2006<!--webbot bot="Timestamp" endspan i-checksum="38516" --></p>
<p><i>Copyright © 2000, 2001 Stephen Cleary (scleary AT jerviswebb DOT
com)</i></p>
<p><i>Distributed under the Boost Software License, Version 1.0. (See
accompanying file <a href="../../../../LICENSE_1_0.txt">LICENSE_1_0.txt</a>
or copy at <a href=
"http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</a>)</i></p>
</body>
</html>
