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162 lines
7.1 KiB
HTML
162 lines
7.1 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>Creates or open a shared memory segment</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.shm-attach" class="refentry">
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<div class="refnamediv">
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<h1 class="refname">shm_attach</h1>
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<p class="verinfo">(PHP 4, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">shm_attach</span> — <span class="dc-title">Creates or open a shared memory segment</span></p>
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</div>
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<div class="refsect1 description" id="refsect1-function.shm-attach-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>shm_attach</strong></span>
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( <span class="methodparam"><span class="type">int</span> <code class="parameter">$key</code></span>
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[, <span class="methodparam"><span class="type">int</span> <code class="parameter">$memsize</code></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="type">resource</span></div>
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<p class="para rdfs-comment">
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<span class="function"><strong>shm_attach()</strong></span> returns an id that can be used to access
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the System V shared memory with the given <code class="parameter">key</code>, the
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first call creates the shared memory segment with
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<code class="parameter">memsize</code> and the optional perm-bits
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<code class="parameter">perm</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>shm_attach()</strong></span> for the same
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<code class="parameter">key</code> will return a different shared memory
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identifier, but both identifiers access the same underlying
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shared memory. <code class="parameter">memsize</code> and
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<code class="parameter">perm</code> will be ignored.
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</p>
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</div>
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<div class="refsect1 parameters" id="refsect1-function.shm-attach-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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A numeric shared memory segment ID
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</p>
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</dd>
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<dt>
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<code class="parameter">memsize</code></dt>
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<dd>
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<p class="para">
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The memory size. If not provided, default to the
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<em>sysvshm.init_mem</em> in the <var class="filename">php.ini</var>, otherwise 10000
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bytes.
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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 optional permission bits. Default to 0666.
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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.shm-attach-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 shared memory segment identifier.
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</p>
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</div>
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<div class="refsect1 changelog" id="refsect1-function.shm-attach-changelog">
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<h3 class="title">更新日志</h3>
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<p class="para">
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<table class="doctable informaltable">
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<thead>
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<tr>
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<th>版本</th>
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<th>说明</th>
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</tr>
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</thead>
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<tbody class="tbody">
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<tr>
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<td>5.3.0</td>
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<td>
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This function now returns a <a href="language.types.resource.html" class="link">资源(resource)</a> instead of an
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<a href="language.types.integer.html" class="link">integer</a>.
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</td>
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</tr>
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</tbody>
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</table>
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</p>
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</div>
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<div class="refsect1 notes" id="refsect1-function.shm-attach-notes">
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<h3 class="title">注释</h3>
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<blockquote class="note"><p><strong class="note">Note</strong>:
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<p class="para">
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This function used to return an integer value prior to
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PHP 5.3.0. To achieve the same value in a portable manner, the
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return value can be cast to an integer like:
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</p>
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<p class="para">
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<div class="example" id="example-4453">
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<div class="example-contents">
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<div class="phpcode"><pre><span style="color: #000000">
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<span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">// Create a temporary file and return its path<br /></span><span style="color: #0000BB">$tmp </span><span style="color: #007700">= </span><span style="color: #0000BB">tempnam</span><span style="color: #007700">(</span><span style="color: #DD0000">'/tmp'</span><span style="color: #007700">, </span><span style="color: #DD0000">'PHP'</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// Get the file token key<br /></span><span style="color: #0000BB">$key </span><span style="color: #007700">= </span><span style="color: #0000BB">ftok</span><span style="color: #007700">(</span><span style="color: #0000BB">$tmp</span><span style="color: #007700">, </span><span style="color: #DD0000">'a'</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// Attach the SHM resource, notice the cast afterwards<br /></span><span style="color: #0000BB">$id </span><span style="color: #007700">= </span><span style="color: #0000BB">shm_attach</span><span style="color: #007700">(</span><span style="color: #0000BB">$key</span><span style="color: #007700">);<br /><br />if (</span><span style="color: #0000BB">$id </span><span style="color: #007700">=== </span><span style="color: #0000BB">false</span><span style="color: #007700">) {<br /> die(</span><span style="color: #DD0000">'Unable to create the shared memory segment'</span><span style="color: #007700">);<br />}<br /><br /></span><span style="color: #FF8000">// Cast to integer, since prior to PHP 5.3.0 the resource id <br />// is returned which can be exposed when casting a resource<br />// to an integer<br /></span><span style="color: #0000BB">$id </span><span style="color: #007700">= (integer) </span><span style="color: #0000BB">$id</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">?></span>
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</span>
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</pre></div>
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</div>
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</div>
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</p>
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</p></blockquote>
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</div>
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<div class="refsect1 seealso" id="refsect1-function.shm-attach-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="shm_detach.html" class="function" rel="rdfs-seeAlso">shm_detach()</a> - Disconnects from shared memory segment</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> |