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177 lines
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177 lines
8.1 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>Performs a c library fcntl on fd</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.dio-fcntl" class="refentry">
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<div class="refnamediv">
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<h1 class="refname">dio_fcntl</h1>
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<p class="verinfo">(PHP 4 >= 4.2.0, PHP 5 < 5.1.0)</p><p class="refpurpose"><span class="refname">dio_fcntl</span> — <span class="dc-title">Performs a c library fcntl on fd</span></p>
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</div>
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<div class="refsect1 description" id="refsect1-function.dio-fcntl-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>dio_fcntl</strong></span>
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( <span class="methodparam"><span class="type">resource</span> <code class="parameter">$fd</code></span>
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, <span class="methodparam"><span class="type">int</span> <code class="parameter">$cmd</code></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">$args</code></span>
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] ) : <span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span></div>
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<p class="para rdfs-comment">
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The <span class="function"><strong>dio_fcntl()</strong></span> function performs the
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operation specified by <code class="parameter">cmd</code> on the file
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descriptor <code class="parameter">fd</code>. Some commands require
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additional arguments <code class="parameter">args</code> to be supplied.
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</p>
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</div>
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<div class="refsect1 parameters" id="refsect1-function.dio-fcntl-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">fd</code></dt>
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<dd>
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<p class="para">
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The file descriptor returned by <span class="function"><a href="dio_open.html" class="function">dio_open()</a></span>.
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</p>
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</dd>
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<dt>
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<code class="parameter">cmd</code></dt>
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<dd>
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<p class="para">
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Can be one of the following operations:
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<ul class="itemizedlist">
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<li class="listitem">
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<p class="para">
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<strong><code>F_SETLK</code></strong> - Lock is set or cleared. If the lock
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is held by someone else <span class="function"><strong>dio_fcntl()</strong></span> returns
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-1.
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</p>
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</li>
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<li class="listitem">
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<p class="para">
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<strong><code>F_SETLKW</code></strong> - like <strong><code>F_SETLK</code></strong>,
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but in case the lock is held by someone else,
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<span class="function"><strong>dio_fcntl()</strong></span> waits until the lock is released.
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</p>
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</li>
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<li class="listitem">
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<p class="para">
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<strong><code>F_GETLK</code></strong> - <span class="function"><strong>dio_fcntl()</strong></span>
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returns an associative array (as described below) if someone else
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prevents lock. If there is no obstruction key "type" will set
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to <strong><code>F_UNLCK</code></strong>.
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</p>
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</li>
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<li class="listitem">
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<p class="para">
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<strong><code>F_DUPFD</code></strong> - finds the lowest numbered available
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file descriptor greater than or equal to <code class="parameter">args</code>
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and returns them.
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</p>
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</li>
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<li class="listitem">
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<p class="para">
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<strong><code>F_SETFL</code></strong> - Sets the file descriptors flags to
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the value specified by <code class="parameter">args</code>, which can be
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<strong><code>O_APPEND</code></strong>, <strong><code>O_NONBLOCK</code></strong> or
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<strong><code>O_ASYNC</code></strong>. To use <strong><code>O_ASYNC</code></strong>
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you will need to use the <a href="ref.pcntl.html" class="link">PCNTL</a>
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extension.
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</p>
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</li>
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</ul>
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</p>
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</dd>
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<dt>
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<code class="parameter">args</code></dt>
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<dd>
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<p class="para">
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<code class="parameter">args</code> is an associative array, when
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<code class="parameter">cmd</code> is <strong><code>F_SETLK</code></strong> or
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<strong><code>F_SETLLW</code></strong>, with the following keys:
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<ul class="itemizedlist">
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<li class="listitem">
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<p class="para">
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<em>start</em> - offset where lock begins
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</p>
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</li>
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<li class="listitem">
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<p class="para">
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<em>length</em> - size of locked area. zero means to end
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of file
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</p>
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</li>
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<li class="listitem">
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<p class="para">
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<em>whence</em> - Where l_start is relative to: can be
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<strong><code>SEEK_SET</code></strong>,
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<strong><code>SEEK_END</code></strong> and <strong><code>SEEK_CUR</code></strong>
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</p>
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</li>
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<li class="listitem">
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<p class="para">
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<em>type</em> - type of lock: can be
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<strong><code>F_RDLCK</code></strong> (read lock),
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<strong><code>F_WRLCK</code></strong> (write lock) or
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<strong><code>F_UNLCK</code></strong> (unlock)
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</p>
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</li>
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</ul>
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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.dio-fcntl-returnvalues">
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<h3 class="title">返回值</h3>
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<p class="para">
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Returns the result of the C call.
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</p>
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</div>
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<div class="refsect1 examples" id="refsect1-function.dio-fcntl-examples">
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<h3 class="title">范例</h3>
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<p class="para">
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<div class="example" id="example-2742">
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<p><strong>Example #1 Setting and clearing a lock</strong></p>
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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 /><br />$fd </span><span style="color: #007700">= </span><span style="color: #0000BB">dio_open</span><span style="color: #007700">(</span><span style="color: #DD0000">'/dev/ttyS0'</span><span style="color: #007700">, </span><span style="color: #0000BB">O_RDWR</span><span style="color: #007700">);<br /><br />if (</span><span style="color: #0000BB">dio_fcntl</span><span style="color: #007700">(</span><span style="color: #0000BB">$fd</span><span style="color: #007700">, </span><span style="color: #0000BB">F_SETLK</span><span style="color: #007700">, Array(</span><span style="color: #DD0000">"type"</span><span style="color: #007700">=></span><span style="color: #0000BB">F_WRLCK</span><span style="color: #007700">)) == -</span><span style="color: #0000BB">1</span><span style="color: #007700">) {<br /> </span><span style="color: #FF8000">// the file descriptor appears locked<br /> </span><span style="color: #007700">echo </span><span style="color: #DD0000">"The lock can not be cleared. It is held by someone else."</span><span style="color: #007700">;<br />} else {<br /> echo </span><span style="color: #DD0000">"Lock successfully set/cleared"</span><span style="color: #007700">;<br />}<br /><br /></span><span style="color: #0000BB">dio_close</span><span style="color: #007700">(</span><span style="color: #0000BB">$fd</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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</div>
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<div class="refsect1 notes" id="refsect1-function.dio-fcntl-notes">
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<h3 class="title">注释</h3>
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<blockquote class="note"><p><strong class="note">Note</strong>: <span class="simpara">此函数未在 Windows 平台下实现。</span></p></blockquote>
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</div>
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</div></div></div></body></html> |