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diff --git a/doc/html/barrier.html b/doc/html/barrier.html new file mode 100644 index 0000000000..1f8724fd2f --- /dev/null +++ b/doc/html/barrier.html @@ -0,0 +1,117 @@ +<html> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> +<title>Class barrier</title> +<link rel="stylesheet" href="boostbook.css" type="text/css"> +<meta name="generator" content="DocBook XSL Stylesheets V1.68.1"> +<link rel="start" href="index.html" title="The Boost C++ Libraries"> +<link rel="up" href="threads/reference.html#id759234" title="Header <boost/thread/barrier.hpp>"> +<link rel="prev" href="threads/reference.html" title="Reference"> +<link rel="next" href="condition.html" title="Class condition"> +</head> +<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> +<table cellpadding="2" width="100%"> +<td valign="top"><img alt="boost.png (6897 bytes)" width="277" height="86" src="../../boost.png"></td> +<td align="center"><a href="../../index.htm">Home</a></td> +<td align="center"><a href="../../libs/libraries.htm">Libraries</a></td> +<td align="center"><a href="../../people/people.htm">People</a></td> +<td align="center"><a href="../../more/faq.htm">FAQ</a></td> +<td align="center"><a href="../../more/index.htm">More</a></td> +</table> +<hr> +<div class="spirit-nav"> +<a accesskey="p" href="threads/reference.html"><img src="images/prev.png" alt="Prev"></a><a accesskey="u" href="threads/reference.html#id759234"><img src="images/up.png" alt="Up"></a><a accesskey="h" href="index.html"><img src="images/home.png" alt="Home"></a><a accesskey="n" href="condition.html"><img src="images/next.png" alt="Next"></a> +</div> +<div class="refentry" lang="en"> +<a name="barrier"></a><div class="titlepage"></div> +<div class="refnamediv"> +<h2><span class="refentrytitle">Class barrier</span></h2> +<p>boost::barrier — <p>An object of class <a href="barrier.html" title="Class barrier">barrier</a> is a synchronization + primitive used to cause a set of threads to wait until they each perform a + certain function or each reach a particular point in their execution.</p></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="bold"><strong>class</strong></span> barrier : <span class="bold"><strong>private</strong></span> boost::noncopyable <span class="emphasis"><em>// Exposition only</em></span> +{ +<span class="bold"><strong>public</strong></span>: + <span class="emphasis"><em>// <a href="barrier.html#barrierconstruct-copy-destruct">construct/copy/destruct</a></em></span> + <a href="barrier.html#id1008465-bb">barrier</a>(size_t); + <a href="barrier.html#id683382-bb">~barrier</a>(); + + <span class="emphasis"><em>// <a href="barrier.html#id942530-bb">waiting</a></em></span> + <span class="type"><span class="bold"><strong>bool</strong></span></span> <a href="barrier.html#id1178178-bb">wait</a>(); +};</pre></div> +<div class="refsect1" lang="en"> +<a name="id1556579"></a><h2>Description</h2> +<p>When a barrier is created, it is initialized with a thread count N. + The first N-1 calls to <code class="computeroutput">wait()</code> will all cause their threads to be blocked. + The Nth call to <code class="computeroutput">wait()</code> will allow all of the waiting threads, including + the Nth thread, to be placed in a ready state. The Nth call will also "reset" + the barrier such that, if an additional N+1th call is made to <code class="computeroutput">wait()</code>, + it will be as though this were the first call to <code class="computeroutput">wait()</code>; in other + words, the N+1th to 2N-1th calls to <code class="computeroutput">wait()</code> will cause their + threads to be blocked, and the 2Nth call to <code class="computeroutput">wait()</code> will allow all of + the waiting threads, including the 2Nth thread, to be placed in a ready state + and reset the barrier. This functionality allows the same set of N threads to re-use + a barrier object to synchronize their execution at multiple points during their + execution.</p> +<p>See <a href="threads.html#threads.glossary" title="Glossary">Glossary</a> for definitions of thread + states <a href="threads.html#threads.glossary.thread-state">blocked</a> + and <a href="threads.html#threads.glossary.thread-state">ready</a>. + Note that "waiting" is a synonym for blocked.</p> +<div class="refsect2" lang="en"> +<a name="id1556658"></a><h3> +<a name="barrierconstruct-copy-destruct"></a><code class="computeroutput">barrier</code> construct/copy/destruct</h3> +<div class="orderedlist"><ol type="1"> +<li> +<pre class="literallayout"><a name="id1008465-bb"></a>barrier(size_t count);</pre> +<p><b xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision"><span class="term">Effects</span></b>: + + Constructs a <a href="barrier.html" title="Class barrier">barrier</a> object that + will cause <code class="computeroutput">count</code> threads to block on a call to <code class="computeroutput">wait()</code>. + </p> +</li> +<li> +<pre class="literallayout"><a name="id683382-bb"></a>~barrier();</pre> +<p><b xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision"><span class="term">Effects</span></b>: + + Destroys <code class="computeroutput">*this</code>. If threads are still executing + their <code class="computeroutput">wait()</code> operations, the behavior for these threads is undefined. + </p> +</li> +</ol></div> +</div> +<div class="refsect2" lang="en"> +<a name="id1556757"></a><h3> +<a name="id942530-bb"></a><code class="computeroutput">barrier</code> waiting</h3> +<div class="orderedlist"><ol type="1"><li> +<pre class="literallayout"><span class="type"><span class="bold"><strong>bool</strong></span></span> <a name="id1178178-bb"></a>wait();</pre> +<p><b xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision"><span class="term">Effects</span></b>: + + Wait until N threads call <code class="computeroutput">wait()</code>, where + N equals the <code class="computeroutput">count</code> provided to the constructor for the + barrier object.<p><span class="bold"><strong>Note</strong></span> that if the barrier is + destroyed before <code class="computeroutput">wait()</code> can return, the behavior is + undefined.</p><br><b xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision"><span class="term">Returns</span></b>: + + Exactly one of the N threads will receive a return value + of <code class="computeroutput">true</code>, the others will receive a value of <code class="computeroutput">false</code>. + Precisely which thread receives the return value of <code class="computeroutput">true</code> will + be implementation-defined. Applications can use this value to designate one + thread as a leader that will take a certain action, and the other threads + emerging from the barrier can wait for that action to take place.</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"><small>Copyright © 2001-2003 William E. Kempf</small></td> +</tr></table> +<hr> +<div class="spirit-nav"> +<a accesskey="p" href="threads/reference.html"><img src="images/prev.png" alt="Prev"></a><a accesskey="u" href="threads/reference.html#id759234"><img src="images/up.png" alt="Up"></a><a accesskey="h" href="index.html"><img src="images/home.png" alt="Home"></a><a accesskey="n" href="condition.html"><img src="images/next.png" alt="Next"></a> +</div> +</body> +</html> |