<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <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 V1.78.1"> <link rel="home" href="../../index.html" title="The Boost C++ Libraries BoostBook Documentation Subset"> <link rel="up" href="../../interprocess/indexes_reference.html#header.boost.interprocess.sync.interprocess_semaphore_hpp" title="Header <boost/interprocess/sync/interprocess_semaphore.hpp>"> <link rel="prev" href="interpro_idm45879390093552.html" title="Class interprocess_recursive_mutex"> <link rel="next" href="interpro_idm45879390048160.html" title="Class interprocess_sharable_mutex"> </head> <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> <table cellpadding="2" 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href="interpro_idm45879390048160.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> </div> <div 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="../../interprocess/indexes_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#idm45879390055232-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#idm45879390052320-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#idm45879390072048-bb">public member functions</a></span> <span class="keyword">void</span> <a class="link" href="interprocess_semaphore.html#idm45879390071488-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#idm45879390067840-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#idm45879390064208-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#idm45879390060576-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="idm45555311528096"></a><h2>Description</h2> <p>Wraps a <a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a> that can be placed in shared memory and can be shared between processes. Allows timed lock tries </p> <div class="refsect2"> <a name="idm45555311526720"></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="idm45879390055232-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 <code class="computeroutput"><a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a></code> with the given initial count. <code class="computeroutput"><a class="link" href="interprocess_exception.html" title="Class interprocess_exception">interprocess_exception</a></code> if there is an error. </p> </li> <li class="listitem"> <pre class="literallayout"><a name="idm45879390052320-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 <code class="computeroutput"><a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a></code>. Does not throw </p> </li> </ol></div> </div> <div class="refsect2"> <a name="idm45555311513040"></a><h3> <a name="idm45879390072048-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="idm45879390071488-bb"></a><span class="identifier">post</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre> <p>Increments the <code class="computeroutput"><a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a></code> count. If there are processes/threads blocked waiting for the <code class="computeroutput"><a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a></code>, then one of these processes will return successfully from its wait function. If there is an error an <code class="computeroutput"><a class="link" href="interprocess_exception.html" title="Class interprocess_exception">interprocess_exception</a></code> exception is thrown. </p> </li> <li class="listitem"> <pre class="literallayout"><span class="keyword">void</span> <a name="idm45879390067840-bb"></a><span class="identifier">wait</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre> <p>Decrements the <code class="computeroutput"><a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a></code>. If the <code class="computeroutput"><a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a></code> value is not greater than zero, then the calling process/thread blocks until it can decrement the counter. If there is an error an <code class="computeroutput"><a class="link" href="interprocess_exception.html" title="Class interprocess_exception">interprocess_exception</a></code> exception is thrown. </p> </li> <li class="listitem"> <pre class="literallayout"><span class="keyword">bool</span> <a name="idm45879390064208-bb"></a><span class="identifier">try_wait</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre> <p>Decrements the <code class="computeroutput"><a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a></code> if the <code class="computeroutput"><a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a></code>'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 <code class="computeroutput"><a class="link" href="interprocess_exception.html" title="Class interprocess_exception">interprocess_exception</a></code> exception is thrown. </p> </li> <li class="listitem"> <pre class="literallayout"><span class="keyword">bool</span> <a name="idm45879390060576-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 <code class="computeroutput"><a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a></code> if the <code class="computeroutput"><a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a></code>'s value is greater than zero and returns true. Otherwise, waits for the <code class="computeroutput"><a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a></code> to the posted or the timeout expires. If the timeout expires, the function returns false. If the <code class="computeroutput"><a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a></code> 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 © 2005-2015 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="interpro_idm45879390093552.html"><img src="../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../interprocess/indexes_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="interpro_idm45879390048160.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> </div> </body> </html>