<!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=UTF-8">
<title>Acquire a semaphore</title>
</head>
<body><div class="manualnavbar" style="text-align: center;">
<div class="prev" style="text-align: left; float: left;"><a href="function.msg-stat-queue.html">msg_stat_queue</a></div>
<div class="next" style="text-align: right; float: right;"><a href="function.sem-get.html">sem_get</a></div>
<div class="up"><a href="ref.sem.html">Semaphore Functions</a></div>
<div class="home"><a href="index.html">PHP Manual</a></div>
</div><hr /><div id="function.sem-acquire" class="refentry">
<div class="refnamediv">
<h1 class="refname">sem_acquire</h1>
<p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">sem_acquire</span> — <span class="dc-title">Acquire a semaphore</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.sem-acquire-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type">bool</span> <span class="methodname"><strong>sem_acquire</strong></span>
( <span class="methodparam"><span class="type">resource</span> <code class="parameter">$sem_identifier</code></span>
)</div>
<p class="para rdfs-comment">
<span class="function"><strong>sem_acquire()</strong></span> blocks (if necessary) until the semaphore
can be acquired. A process attempting to acquire a semaphore which it has
already acquired will block forever if acquiring the semaphore would cause
its maximum number of semaphore to be exceeded.
</p>
<p class="para">
After processing a request, any semaphores acquired by the process but not
explicitly released will be released automatically and a warning will be
generated.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.sem-acquire-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term"><em><code class="parameter">sem_identifier</code></em></span>
<dd>
<p class="para">
<em><code class="parameter">sem_identifier</code></em> is a semaphore resource,
obtained from <span class="function"><a href="function.sem-get.html" class="function">sem_get()</a></span>.
</p>
</dd>
</dt>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.sem-acquire-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns <strong><code>TRUE</code></strong> on success or <strong><code>FALSE</code></strong> on failure.
</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.sem-acquire-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"> <span class="function"><a href="function.sem-get.html" class="function" rel="rdfs-seeAlso">sem_get()</a> - Get a semaphore id</span></li>
<li class="member"> <span class="function"><a href="function.sem-release.html" class="function" rel="rdfs-seeAlso">sem_release()</a> - Release a semaphore</span></li>
</ul>
</p>
</div>
</div><hr /><div class="manualnavbar" style="text-align: center;">
<div class="prev" style="text-align: left; float: left;"><a href="function.msg-stat-queue.html">msg_stat_queue</a></div>
<div class="next" style="text-align: right; float: right;"><a href="function.sem-get.html">sem_get</a></div>
<div class="up"><a href="ref.sem.html">Semaphore Functions</a></div>
<div class="home"><a href="index.html">PHP Manual</a></div>
</div></body></html>
