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134 lines
4.4 KiB
HTML
134 lines
4.4 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<head>
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<meta http-equiv="content-type" content="text/html; charset=UTF-8">
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<title>Get a semaphore id</title>
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</head>
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<body class="docs"><div id="layout">
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<div id="layout-content"><div id="function.sem-get" class="refentry">
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<div class="refnamediv">
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<h1 class="refname">sem_get</h1>
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<p class="verinfo">(PHP 4, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">sem_get</span> — <span class="dc-title">Get a semaphore id</span></p>
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</div>
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<div class="refsect1 description" id="refsect1-function.sem-get-description">
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<h3 class="title">说明</h3>
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<div class="methodsynopsis dc-description">
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<span class="methodname"><strong>sem_get</strong></span>
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( <span class="methodparam"><span class="type">int</span> <code class="parameter">$key</code></span>
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[, <span class="methodparam"><span class="type">int</span> <code class="parameter">$max_acquire</code><span class="initializer"> = 1</span></span>
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[, <span class="methodparam"><span class="type">int</span> <code class="parameter">$perm</code><span class="initializer"> = 0666</span></span>
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[, <span class="methodparam"><span class="type">int</span> <code class="parameter">$auto_release</code><span class="initializer"> = 1</span></span>
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]]] ) : <span class="type">resource</span></div>
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<p class="para rdfs-comment">
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<span class="function"><strong>sem_get()</strong></span> returns an id that can be used to
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access the System V semaphore with the given <code class="parameter">key</code>.
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</p>
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<p class="para">
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A second call to <span class="function"><strong>sem_get()</strong></span> for the same key
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will return a different semaphore identifier, but both
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identifiers access the same underlying semaphore.
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</p>
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</div>
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<div class="refsect1 parameters" id="refsect1-function.sem-get-parameters">
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<h3 class="title">参数</h3>
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<p class="para">
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<dl>
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<dt>
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<code class="parameter">key</code></dt>
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<dd>
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<p class="para">
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</p>
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</dd>
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<dt>
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<code class="parameter">max_acquire</code></dt>
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<dd>
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<p class="para">
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The number of processes that can acquire the semaphore simultaneously
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is set to <code class="parameter">max_acquire</code>.
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</p>
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</dd>
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<dt>
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<code class="parameter">perm</code></dt>
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<dd>
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<p class="para">
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The semaphore permissions. Actually this value is
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set only if the process finds it is the only process currently
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attached to the semaphore.
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</p>
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</dd>
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<dt>
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<code class="parameter">auto_release</code></dt>
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<dd>
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<p class="para">
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Specifies if the semaphore should be automatically released on request
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shutdown.
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</p>
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</dd>
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</dl>
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</p>
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</div>
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<div class="refsect1 returnvalues" id="refsect1-function.sem-get-returnvalues">
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<h3 class="title">返回值</h3>
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<p class="para">
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Returns a positive semaphore identifier on success, or <strong><code>FALSE</code></strong> on
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error.
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</p>
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</div>
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<div class="refsect1 notes" id="refsect1-function.sem-get-notes">
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<h3 class="title">注释</h3>
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<div class="warning"><strong class="warning">Warning</strong>
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<p class="simpara">
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When using <span class="function"><strong>sem_get()</strong></span> to access a semaphore created
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outside PHP, note that the semaphore must have been created as a set of 3
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semaphores (for example, by specifying 3 as the <em>nsems</em>
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parameter when calling the C <em>semget()</em> function),
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otherwise PHP will be unable to access the semaphore.
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</p>
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</div>
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</div>
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<div class="refsect1 seealso" id="refsect1-function.sem-get-seealso">
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<h3 class="title">参见</h3>
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<p class="para">
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<ul class="simplelist">
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<li class="member"><span class="function"><a href="sem_acquire.html" class="function" rel="rdfs-seeAlso">sem_acquire()</a> - Acquire a semaphore</span></li>
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<li class="member"><span class="function"><a href="sem_release.html" class="function" rel="rdfs-seeAlso">sem_release()</a> - Release a semaphore</span></li>
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<li class="member"><span class="function"><a href="ftok.html" class="function" rel="rdfs-seeAlso">ftok()</a> - Convert a pathname and a project identifier to a System V IPC key</span></li>
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</ul>
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</p>
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</div>
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</div></div></div></body></html> |