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160 lines
4.8 KiB
HTML
160 lines
4.8 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>Perform file readahead into page cache</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.eio-readahead" class="refentry">
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<div class="refnamediv">
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<h1 class="refname">eio_readahead</h1>
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<p class="verinfo">(PECL eio >= 0.0.1dev)</p><p class="refpurpose"><span class="refname">eio_readahead</span> — <span class="dc-title">Perform file readahead into page cache</span></p>
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</div>
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<div class="refsect1 description" id="refsect1-function.eio-readahead-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>eio_readahead</strong></span>
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( <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$fd</code></span>
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, <span class="methodparam"><span class="type">int</span> <code class="parameter">$offset</code></span>
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, <span class="methodparam"><span class="type">int</span> <code class="parameter">$length</code></span>
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[, <span class="methodparam"><span class="type">int</span> <code class="parameter">$pri</code><span class="initializer"> = EIO_PRI_DEFAULT</span></span>
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[, <span class="methodparam"><span class="type"><a href="language.types.callable.html" class="type callable">callable</a></span> <code class="parameter">$callback</code><span class="initializer"> = NULL</span></span>
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[, <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$data</code><span class="initializer"> = NULL</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>eio_readahead()</strong></span> populates the page cache with data from a file so that subsequent reads from
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that file will not block on disk I/O. See <em>READAHEAD(2)</em> man page for details.
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</p>
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</div>
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<div class="refsect1 parameters" id="refsect1-function.eio-readahead-parameters">
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<h3 class="title">参数</h3>
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<dl>
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<dt>
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<code class="parameter">fd</code></dt>
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<dd>
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<p class="para">
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Stream, Socket resource, or numeric file descriptor
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</p>
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</dd>
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<dt>
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<code class="parameter">offset</code></dt>
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<dd>
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<p class="para">
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Starting point from which data is to be read.
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</p>
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</dd>
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<dt>
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<code class="parameter">length</code></dt>
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<dd>
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<p class="para">
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Number of bytes to be read.
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</p>
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</dd>
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<dt>
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<code class="parameter">pri</code></dt>
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<dd>
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<p class="para">请求的优先级：<strong><code>EIO_PRI_DEFAULT</code></strong>，<strong><code>EIO_PRI_MIN</code></strong>，<strong><code>EIO_PRI_MAX</code></strong> 或 <strong><code>NULL</code></strong>。如果是
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<strong><code>NULL</code></strong>，<code class="parameter">pri</code> 将设为
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<strong><code>EIO_PRI_DEFAULT</code></strong>。
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</p>
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</dd>
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<dt>
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<code class="parameter">callback</code></dt>
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<dd>
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<p class="para">
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<code class="parameter">callback</code>
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函数在请求完成时被调用。其应匹配一下原型：<div class="example-contents"><div class="phpcode"><pre><span style="color: #000000">
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void callback(mixed $data, int $result[, resource $req]);</span>
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</pre></div></div>
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<dl>
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<dt>
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<code class="parameter">data</code></dt>
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<dd>
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<p class="para">传递给请求的用户数据。</p></dd>
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<dt>
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<code class="parameter">result</code></dt>
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<dd>
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<p class="para">针对请求的结果的值。通常是相应的系统调用返回的值。</p></dd>
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<dt>
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<code class="parameter">req</code></dt>
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<dd>
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<p class="para">可选的请求资源，可被 <span class="function"><a href="eio_get_last_error.html" class="function">eio_get_last_error()</a></span>
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之类的函数使用。</p></dd>
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</dl>
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</p>
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</dd>
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<dt>
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<code class="parameter">data</code></dt>
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<dd>
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<p class="para">
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Arbitrary variable passed to <code class="parameter">callback</code>.
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</p>
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</dd>
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</dl>
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</div>
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<div class="refsect1 returnvalues" id="refsect1-function.eio-readahead-returnvalues">
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<h3 class="title">返回值</h3>
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<p class="para">
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<span class="function"><strong>eio_readahead()</strong></span> returns request resource on success or <strong><code>FALSE</code></strong> on error.
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</p>
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</div>
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</div></div></div></body></html> |