1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2<html> 3<head> 4<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 5<title>Class interprocess_semaphore</title> 6<link rel="stylesheet" href="../../../../doc/src/boostbook.css" type="text/css"> 7<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 8<link rel="home" href="../../index.html" title="The Boost C++ Libraries BoostBook Documentation Subset"> 9<link rel="up" href="../../interprocess/indexes_reference.html#header.boost.interprocess.sync.interprocess_semaphore_hpp" title="Header <boost/interprocess/sync/interprocess_semaphore.hpp>"> 10<link rel="prev" href="interpro_idm45304010361200.html" title="Class interprocess_recursive_mutex"> 11<link rel="next" href="interpro_idm45304010315808.html" title="Class interprocess_sharable_mutex"> 12</head> 13<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 14<table 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href="interpro_idm45304010315808.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> 25</div> 26<div class="refentry"> 27<a name="boost.interprocess.interprocess_semaphore"></a><div class="titlepage"></div> 28<div class="refnamediv"> 29<h2><span class="refentrytitle">Class interprocess_semaphore</span></h2> 30<p>boost::interprocess::interprocess_semaphore</p> 31</div> 32<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2> 33<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>> 34 35</span> 36<span class="keyword">class</span> <a class="link" href="interprocess_semaphore.html" title="Class interprocess_semaphore">interprocess_semaphore</a> <span class="special">{</span> 37<span class="keyword">public</span><span class="special">:</span> 38 <span class="comment">// <a class="link" href="interprocess_semaphore.html#boost.interprocess.interprocess_semaphoreconstruct-copy-destruct">construct/copy/destruct</a></span> 39 <a class="link" href="interprocess_semaphore.html#idm45304010322880-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> 40 <a class="link" href="interprocess_semaphore.html#idm45304010319968-bb"><span class="special">~</span><span class="identifier">interprocess_semaphore</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span> 41 42 <span class="comment">// <a class="link" href="interprocess_semaphore.html#idm45304010339696-bb">public member functions</a></span> 43 <span class="keyword">void</span> <a class="link" href="interprocess_semaphore.html#idm45304010339136-bb"><span class="identifier">post</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span> 44 <span class="keyword">void</span> <a class="link" href="interprocess_semaphore.html#idm45304010335488-bb"><span class="identifier">wait</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span> 45 <span class="keyword">bool</span> <a class="link" href="interprocess_semaphore.html#idm45304010331856-bb"><span class="identifier">try_wait</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span> 46 <span class="keyword">bool</span> <a class="link" href="interprocess_semaphore.html#idm45304010328224-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> 47<span class="special">}</span><span class="special">;</span></pre></div> 48<div class="refsect1"> 49<a name="id-1.3.19.17.3.62.4.4"></a><h2>Description</h2> 50<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> 51<div class="refsect2"> 52<a name="id-1.3.19.17.3.62.4.4.3"></a><h3> 53<a name="boost.interprocess.interprocess_semaphoreconstruct-copy-destruct"></a><code class="computeroutput">interprocess_semaphore</code> 54 public 55 construct/copy/destruct</h3> 56<div class="orderedlist"><ol class="orderedlist" type="1"> 57<li class="listitem"> 58<pre class="literallayout"><a name="idm45304010322880-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> 59<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> 60</li> 61<li class="listitem"> 62<pre class="literallayout"><a name="idm45304010319968-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> 63<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> 64</li> 65</ol></div> 66</div> 67<div class="refsect2"> 68<a name="id-1.3.19.17.3.62.4.4.4"></a><h3> 69<a name="idm45304010339696-bb"></a><code class="computeroutput">interprocess_semaphore</code> public member functions</h3> 70<div class="orderedlist"><ol class="orderedlist" type="1"> 71<li class="listitem"> 72<pre class="literallayout"><span class="keyword">void</span> <a name="idm45304010339136-bb"></a><span class="identifier">post</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre> 73<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> 74</li> 75<li class="listitem"> 76<pre class="literallayout"><span class="keyword">void</span> <a name="idm45304010335488-bb"></a><span class="identifier">wait</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre> 77<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> 78</li> 79<li class="listitem"> 80<pre class="literallayout"><span class="keyword">bool</span> <a name="idm45304010331856-bb"></a><span class="identifier">try_wait</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre> 81<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> 82</li> 83<li class="listitem"> 84<pre class="literallayout"><span class="keyword">bool</span> <a name="idm45304010328224-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> 85<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> 86</li> 87</ol></div> 88</div> 89</div> 90</div> 91<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 92<td align="left"></td> 93<td align="right"><div class="copyright-footer">Copyright © 2005-2015 Ion Gaztanaga<p> 94 Distributed under the Boost Software License, Version 1.0. (See accompanying 95 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>) 96 </p> 97</div></td> 98</tr></table> 99<hr> 100<div class="spirit-nav"> 101<a accesskey="p" href="interpro_idm45304010361200.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_idm45304010315808.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> 102</div> 103</body> 104</html> 105
