function.dio-fcntl.html
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html> <head> <title>Performs a c library fcntl on fd</title> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> </head> <body><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.dio-close.html">dio_close</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.dio-open.html">dio_open</a></div> <div class="up"><a href="ref.dio.html">Direct IO Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div><hr /><div id="function.dio-fcntl" class="refentry"> <div class="refnamediv"> <h1 class="refname">dio_fcntl</h1> <p class="verinfo">(PHP 4 >= 4.2.0, PHP 5 <= 5.0.5)</p><p class="refpurpose"><span class="refname">dio_fcntl</span> — <span class="dc-title">Performs a c library fcntl on fd</span></p> </div> <div class="refsect1 description"> <h3 class="title">Description</h3> <div class="methodsynopsis dc-description"> <span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <span class="methodname"><b><b>dio_fcntl</b></b></span> ( <span class="methodparam"><span class="type">resource</span> <tt class="parameter">$fd</tt></span> , <span class="methodparam"><span class="type">int</span> <tt class="parameter">$cmd</tt></span> [, <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <tt class="parameter">$args</tt></span> ] )</div> <p class="para rdfs-comment"> The <b>dio_fcntl()</b> function performs the operation specified by <i><tt class="parameter">cmd</tt></i> on the file descriptor <i><tt class="parameter">fd</tt></i>. Some commands require additional arguments <i><tt class="parameter">args</tt></i> to be supplied. </p> </div> <div class="refsect1 parameters"> <h3 class="title">Parameters</h3> <p class="para"> <dl> <dt> <span class="term"><i><tt class="parameter">fd</tt></i></span> <dd> <p class="para"> The file descriptor returned by <a href="function.dio-open.html" class="function">dio_open()</a>. </p> </dd> </dt> <dt> <span class="term"><i><tt class="parameter">cmd</tt></i></span> <dd> <p class="para"> Can be one of the following operations: <ul class="itemizedlist"> <li class="listitem"> <p class="para"> <b><tt>F_SETLK</tt></b> - Lock is set or cleared. If the lock is held by someone else <b>dio_fcntl()</b> returns -1. </p> </li> <li class="listitem"> <p class="para"> <b><tt>F_SETLKW</tt></b> - like <b><tt>F_SETLK</tt></b>, but in case the lock is held by someone else, <b>dio_fcntl()</b> waits until the lock is released. </p> </li> <li class="listitem"> <p class="para"> <b><tt>F_GETLK</tt></b> - <b>dio_fcntl()</b> returns an associative array (as described above) if someone else prevents lock. If there is no obstruction key "type" will set to <b><tt>F_UNLCK</tt></b>. </p> </li> <li class="listitem"> <p class="para"> <b><tt>F_DUPFD</tt></b> - finds the lowest numbered available file descriptor greater than or equal to <i><tt class="parameter">args</tt></i> and returns them. </p> </li> <li class="listitem"> <p class="para"> <b><tt>F_SETFL</tt></b> - Sets the file descriptors flags to the value specified by <i><tt class="parameter">args</tt></i>, which can be <b><tt>O_APPEND</tt></b>, <b><tt>O_NONBLOCK</tt></b> or <b><tt>O_ASYNC</tt></b>. To use <b><tt>O_ASYNC</tt></b> you will need to use the <a href="ref.pcntl.html" class="link">PCNTL</a> extension. </p> </li> </ul> </p> </dd> </dt> <dt> <span class="term"><i><tt class="parameter">args</tt></i></span> <dd> <p class="para"> <i><tt class="parameter">args</tt></i> is an associative array, when <i><tt class="parameter">cmd</tt></i> is <b><tt>F_SETLK</tt></b> or <b><tt>F_SETLLW</tt></b>, with the following keys: <ul class="itemizedlist"> <li class="listitem"> <p class="para"> "start" - offset where lock begins </p> </li> <li class="listitem"> <p class="para"> "length" - size of locked area. zero means to end of file </p> </li> <li class="listitem"> <p class="para"> "wenth" - Where l_start is relative to: can be <b><tt>SEEK_SET</tt></b>, <b><tt>SEEK_END</tt></b> and <b><tt>SEEK_CUR</tt></b> </p> </li> <li class="listitem"> <p class="para"> "type" - type of lock: can be <b><tt>F_RDLCK</tt></b> (read lock), <b><tt>F_WRLCK</tt></b> (write lock) or <b><tt>F_UNLCK</tt></b> (unlock) </p> </li> </ul> </p> </dd> </dt> </dl> </p> </div> <div class="refsect1 returnvalues"> <h3 class="title">Return Values</h3> <p class="para"> Returns the result of the C call. </p> </div> <div class="refsect1 examples"> <h3 class="title">Examples</h3> <p class="para"> <div class="example"> <p><b>Example #1 Setting and clearing a lock</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><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">$fd</span><span style="color: #007700">, </span><span style="color: #0000BB">F_SETLK</span><span style="color: #007700">, Array(</span><span style="color: #DD0000">"type"</span><span style="color: #007700">=></span><span style="color: #0000BB">F_WRLCK</span><span style="color: #007700">)) == -</span><span style="color: #0000BB">1</span><span style="color: #007700">) {<br /> </span><span style="color: #FF8000">// the file descriptor appears locked<br /> </span><span style="color: #007700">echo </span><span style="color: #DD0000">"The lock can not be cleared. It is held by someone else."</span><span style="color: #007700">;<br />} else {<br /> echo </span><span style="color: #DD0000">"Lock succesfully set/cleared"</span><span style="color: #007700">;<br />}<br /><br /></span><span style="color: #0000BB">dio_close</span><span style="color: #007700">(</span><span style="color: #0000BB">$fd</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> </p> </div> <div class="refsect1 notes"> <h3 class="title">Notes</h3> <blockquote><p><b class="note">Note</b>: <span class="simpara">This function is notimplemented on Windows platforms.</span></p></blockquote> </div></div><hr /><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.dio-close.html">dio_close</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.dio-open.html">dio_open</a></div> <div class="up"><a href="ref.dio.html">Direct IO Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div></body></html>⌨️ 快捷键说明
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