Source of: /manual/en/function.sem-get.php
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?>
<div id="function.sem-get" class="refentry">
<div class="refnamediv">
<h1 class="refname">sem_get</h1>
<p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">sem_get</span> — <span class="dc-title">Get a semaphore id</span></p>
</div>
<a name="function.sem-get.description"></a><div class="refsect1 description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type">resource</span> <span class="methodname"><b>sem_get</b></span>
( <span class="methodparam"><span class="type">int</span> <tt class="parameter">$key</tt></span>
[, <span class="methodparam"><span class="type">int</span> <tt class="parameter">$max_acquire</tt></span>
[, <span class="methodparam"><span class="type">int</span> <tt class="parameter">$perm</tt></span>
[, <span class="methodparam"><span class="type">int</span> <tt class="parameter">$auto_release</tt></span>
]]] )</div>
<p class="para rdfs-comment">
<b>sem_get()</b> returns an id that can be used to
access the System V semaphore with the given <i><tt class="parameter">key</tt></i>
.
</p>
<p class="para">
A second call to <b>sem_get()</b> for the same key
will return a different semaphore identifier, but both
identifiers access the same underlying semaphore.
</p>
</div>
<a name="function.sem-get.parameters"></a><div class="refsect1 parameters">
<h3 class="title">Parameters</h3>
<p class="para">
</p><dl>
<dt class="varlistentry">
<span class="term"><i><tt class="parameter">key</tt></i>
</span>
</dt><dd class="listitem">
<p class="para">
</p>
</dd>
<dt class="varlistentry">
<span class="term"><i><tt class="parameter">max_acquire</tt></i>
</span>
</dt><dd class="listitem">
<p class="para">
The number of processes that can acquire the semaphore simultaneously
is set to <i><tt class="parameter">max_acquire</tt></i>
(defaults to 1).
</p>
</dd>
<dt class="varlistentry">
<span class="term"><i><tt class="parameter">perm</tt></i>
</span>
</dt><dd class="listitem">
<p class="para">
The semaphore permissions. Defaults to 0666. Actually this value is
set only if the process finds it is the only process currently
attached to the semaphore.
</p>
</dd>
<dt class="varlistentry">
<span class="term"><i><tt class="parameter">auto_release</tt></i>
</span>
</dt><dd class="listitem">
<p class="para">
Specifies if the semaphore should be automatically released on request
shutdown.
</p>
</dd>
</dl>
<p>
</p>
</div>
<a name="function.sem-get.returnvalues"></a><div class="refsect1 returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns a positive semaphore identifier on success, or <b><tt class="constant">FALSE</tt></b> on
error.
</p>
</div>
<a name="function.sem-get.changelog"></a><div class="refsect1 changelog">
<h3 class="title">Changelog</h3>
<p class="para">
</p><table class="doctable informaltable">
<thead valign="middle">
<tr valign="middle">
<th>Version</th>
<th>Description</th>
</tr>
</thead>
<tbody valign="middle" class="tbody">
<tr valign="middle">
<td align="left">4.3.0</td>
<td align="left">
The <i><tt class="parameter">auto_release</tt></i>
parameter was added.
</td>
</tr>
</tbody>
</table>
<p>
</p>
</div>
<a name="function.sem-get.seealso"></a><div class="refsect1 seealso">
<h3 class="title">See Also</h3>
<p class="para">
</p><ul class="simplelist">
<li class="member"><a href="function.sem-acquire.php" class="function" rel="rdfs-seeAlso">sem_acquire()</a> - Acquire a semaphore</li>
<li class="member"><a href="function.sem-release.php" class="function" rel="rdfs-seeAlso">sem_release()</a> - Release a semaphore</li>
<li class="member"><a href="function.ftok.php" class="function" rel="rdfs-seeAlso">ftok()</a> - Convert a pathname and a project identifier to a System V IPC key</li>
</ul><p>
</p>
</div>
</div><?php manual_footer(); ?>
