<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> <title>Class interprocess_semaphore</title> <link rel="stylesheet" href="../../../../doc/src/boostbook.css" type="text/css"> <meta name="generator" content="DocBook XSL Stylesheets V1.75.2"> <link rel="home" href="../../index.html" title="The Boost C++ Libraries BoostBook Documentation Subset"> <link rel="up" href="../../boost_interprocess_reference.html#header.boost.interprocess.sync.interprocess_semaphore_hpp" title="Header <boost/interprocess/sync/interprocess_semaphore.hpp>"> <link rel="prev" href="interprocess_recursive__id829710.html" title="Class interprocess_recursive_mutex"> <link rel="next" href="interprocess_upgradable_id829946.html" title="Class interprocess_upgradable_mutex"> </head> <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> <table cellpadding="2" width="100%"><tr> <td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" 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class="refentry"> <a name="boost.interprocess.interprocess_semaphore"></a><div class="titlepage"></div> <div class="refnamediv"> <h2><span class="refentrytitle">Class interprocess_semaphore</span></h2> <p>boost::interprocess::interprocess_semaphore</p> </div> <h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2> <div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: <<a class="link" href="../../boost_interprocess_reference.html#header.boost.interprocess.sync.interprocess_semaphore_hpp" title="Header <boost/interprocess/sync/interprocess_semaphore.hpp>">boost/interprocess/sync/interprocess_semaphore.hpp</a>> </span> <span class="keyword">class</span> <a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a> <span class="special">{</span> <span class="keyword">public</span><span class="special">:</span> <span class="comment">// <a class="link" href="interprocess_semaphore.html#boost.interprocess.interprocess_semaphoreconstruct-copy-destruct">construct/copy/destruct</a></span> <a class="link" href="interprocess_semaphore.html#id829915-bb"><span class="identifier">interprocess_semaphore</span></a><span class="special">(</span><span class="keyword">unsigned</span> <span class="keyword">int</span><span class="special">)</span><span class="special">;</span> <a class="link" href="interprocess_semaphore.html#id829927-bb"><span class="special">~</span><span class="identifier">interprocess_semaphore</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span> <span class="comment">// <a class="link" href="interprocess_semaphore.html#id829843-bb">public member functions</a></span> <span class="keyword">void</span> <a class="link" href="interprocess_semaphore.html#id829846-bb"><span class="identifier">post</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span> <span class="keyword">void</span> <a class="link" href="interprocess_semaphore.html#id829862-bb"><span class="identifier">wait</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span> <span class="keyword">bool</span> <a class="link" href="interprocess_semaphore.html#id829877-bb"><span class="identifier">try_wait</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span> <span class="keyword">bool</span> <a class="link" href="interprocess_semaphore.html#id829892-bb"><span class="identifier">timed_wait</span></a><span class="special">(</span><span class="keyword">const</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">posix_time</span><span class="special">::</span><span class="identifier">ptime</span> <span class="special">&</span><span class="special">)</span><span class="special">;</span> <span class="special">}</span><span class="special">;</span></pre></div> <div class="refsect1"> <a name="id1538497"></a><h2>Description</h2> <p>Wraps a interprocess_semaphore that can be placed in shared memory and can be shared between processes. Allows timed lock tries </p> <div class="refsect2"> <a name="id1538505"></a><h3> <a name="boost.interprocess.interprocess_semaphoreconstruct-copy-destruct"></a><code class="computeroutput">interprocess_semaphore</code> public construct/copy/destruct</h3> <div class="orderedlist"><ol class="orderedlist" type="1"> <li class="listitem"> <pre class="literallayout"><a name="id829915-bb"></a><span class="identifier">interprocess_semaphore</span><span class="special">(</span><span class="keyword">unsigned</span> <span class="keyword">int</span> initialCount<span class="special">)</span><span class="special">;</span></pre> <p>Creates a interprocess_semaphore with the given initial count. interprocess_exception if there is an error. </p> </li> <li class="listitem"> <pre class="literallayout"><a name="id829927-bb"></a><span class="special">~</span><span class="identifier">interprocess_semaphore</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre> <p>Destroys the interprocess_semaphore. Does not throw </p> </li> </ol></div> </div> <div class="refsect2"> <a name="id1538607"></a><h3> <a name="id829843-bb"></a><code class="computeroutput">interprocess_semaphore</code> public member functions</h3> <div class="orderedlist"><ol class="orderedlist" type="1"> <li class="listitem"> <pre class="literallayout"><span class="keyword">void</span> <a name="id829846-bb"></a><span class="identifier">post</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre> <p>Increments the interprocess_semaphore count. If there are processes/threads blocked waiting for the interprocess_semaphore, then one of these processes will return successfully from its wait function. If there is an error an interprocess_exception exception is thrown. </p> </li> <li class="listitem"> <pre class="literallayout"><span class="keyword">void</span> <a name="id829862-bb"></a><span class="identifier">wait</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre> <p>Decrements the interprocess_semaphore. If the interprocess_semaphore value is not greater than zero, then the calling process/thread blocks until it can decrement the counter. If there is an error an interprocess_exception exception is thrown. </p> </li> <li class="listitem"> <pre class="literallayout"><span class="keyword">bool</span> <a name="id829877-bb"></a><span class="identifier">try_wait</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre> <p>Decrements the interprocess_semaphore if the interprocess_semaphore's value is greater than zero and returns true. If the value is not greater than zero returns false. If there is an error an interprocess_exception exception is thrown. </p> </li> <li class="listitem"> <pre class="literallayout"><span class="keyword">bool</span> <a name="id829892-bb"></a><span class="identifier">timed_wait</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">posix_time</span><span class="special">::</span><span class="identifier">ptime</span> <span class="special">&</span> abs_time<span class="special">)</span><span class="special">;</span></pre> <p>Decrements the interprocess_semaphore if the interprocess_semaphore's value is greater than zero and returns true. Otherwise, waits for the interprocess_semaphore to the posted or the timeout expires. If the timeout expires, the function returns false. If the interprocess_semaphore is posted the function returns true. If there is an error throws sem_exception </p> </li> </ol></div> </div> </div> </div> <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> <td align="left"></td> <td align="right"><div class="copyright-footer">Copyright © 2005 - 2008 Ion Gaztanaga<p> Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) </p> </div></td> </tr></table> <hr> <div class="spirit-nav"> <a accesskey="p" href="interprocess_recursive__id829710.html"><img src="../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../boost_interprocess_reference.html#header.boost.interprocess.sync.interprocess_semaphore_hpp"><img src="../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="interprocess_upgradable_id829946.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> </div> </body> </html>