📄 function.dl.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>Loads a PHP extension at runtime</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.assert.html">assert</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.extension-loaded.html">extension_loaded</a></div> <div class="up"><a href="ref.info.html">PHP Options/Info Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div><hr /><div id="function.dl" class="refentry"> <div class="refnamediv"> <h1 class="refname">dl</h1> <p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">dl</span> — <span class="dc-title">Loads a PHP extension at runtime</span></p> </div> <div class="refsect1 description"> <h3 class="title">Description</h3> <div class="methodsynopsis dc-description"> <span class="type">int</span> <span class="methodname"><b><b>dl</b></b></span> ( <span class="methodparam"><span class="type">string</span> <tt class="parameter">$library</tt></span> )</div> <p class="para rdfs-comment"> Loads the PHP extension given by the parameter <i><tt class="parameter">library</tt></i>. </p> <p class="para"> Use <a href="function.extension-loaded.html" class="function">extension_loaded()</a> to test whether a given extension is already available or not. This works on both built-in extensions and dynamically loaded ones (either through <var class="filename">php.ini</var> or <b>dl()</b>). </p> </div> <div class="refsect1 parameters"> <h3 class="title">Parameters</h3> <p class="para"> <dl> <dt> <span class="term"><i><tt class="parameter">library</tt></i></span> <dd> <p class="para"> This parameter is <em class="emphasis">only</em> the filename of the extension to load which also depends on your platform. For example, the <a href="ref.sockets.html" class="link">sockets</a> extension (if compiled as a shared module, not the default!) would be called <var class="filename">sockets.so</var> on Unix platforms whereas it is called <var class="filename">php_sockets.dll</var> on the Windows platform. </p> <p class="para"> The directory where the extension is loaded from depends on your platform: </p> <p class="para"> Windows - If not explicitly set in the <var class="filename">php.ini</var>, the extension is loaded from <var class="filename">c:\php4\extensions\</var> by default. </p> <p class="para"> Unix - If not explicitly set in the <var class="filename">php.ini</var>, the default extension directory depends on <ul class="itemizedlist"> <li class="listitem"> <span class="simpara"> whether PHP has been built with <i>--enable-debug</i> or not </span> </li> <li class="listitem"> <span class="simpara"> whether PHP has been built with (experimental) ZTS (Zend Thread Safety) support or not </span> </li> <li class="listitem"> <span class="simpara"> the current internal <i>ZEND_MODULE_API_NO</i> (Zend internal module API number, which is basically the date on which a major module API change happened, e.g. <i>20010901</i>) </span> </li> </ul> Taking into account the above, the directory then defaults to <i><install-dir>/lib/php/extensions/ <debug-or-not>-<zts-or-not>-ZEND_MODULE_API_NO</i>, e.g. <var class="filename">/usr/local/php/lib/php/extensions/debug-non-zts-20010901</var> or <var class="filename">/usr/local/php/lib/php/extensions/no-debug-zts-20010901</var>. </p> </dd> </dt> </dl> </p> </div> <div class="refsect1 returnvalues"> <h3 class="title">Return Values</h3> <p class="para"> Returns <b><tt>TRUE</tt></b> on success or <b><tt>FALSE</tt></b> on failure. If the functionality of loading modules is not available (see Note) or has been disabled (either by turning it off <i>enable_dl</i> or by enabling <a href="features.safe-mode.html#ini.safe-mode" class="link">safe mode</a> in <var class="filename">php.ini</var>) an <b><tt>E_ERROR</tt></b> is emitted and execution is stopped. If <b>dl()</b> fails because the specified library couldn't be loaded, in addition to <b><tt>FALSE</tt></b> an <b><tt>E_WARNING</tt></b> message is emitted. </p> </div> <div class="refsect1 examples"> <h3 class="title">Examples</h3> <p class="para"> <div class="example"> <p><b>Example #1 <b>dl()</b> examples</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">// Example loading an extension based on OS<br /></span><span style="color: #007700">if (!</span><span style="color: #0000BB">extension_loaded</span><span style="color: #007700">(</span><span style="color: #DD0000">'sqlite'</span><span style="color: #007700">)) {<br /> if (</span><span style="color: #0000BB">strtoupper</span><span style="color: #007700">(</span><span style="color: #0000BB">substr</span><span style="color: #007700">(</span><span style="color: #0000BB">PHP_OS</span><span style="color: #007700">, </span><span style="color: #0000BB">0</span><span style="color: #007700">, </span><span style="color: #0000BB">3</span><span style="color: #007700">)) === </span><span style="color: #DD0000">'WIN'</span><span style="color: #007700">) {<br /> </span><span style="color: #0000BB">dl</span><span style="color: #007700">(</span><span style="color: #DD0000">'php_sqlite.dll'</span><span style="color: #007700">);<br /> } else {<br /> </span><span style="color: #0000BB">dl</span><span style="color: #007700">(</span><span style="color: #DD0000">'sqlite.so'</span><span style="color: #007700">);<br /> }<br />}<br /><br /></span><span style="color: #FF8000">// Or, the PHP_SHLIB_SUFFIX constant is available as of PHP 4.3.0<br /></span><span style="color: #007700">if (!</span><span style="color: #0000BB">extension_loaded</span><span style="color: #007700">(</span><span style="color: #DD0000">'sqlite'</span><span style="color: #007700">)) {<br /> </span><span style="color: #0000BB">$prefix </span><span style="color: #007700">= (</span><span style="color: #0000BB">PHP_SHLIB_SUFFIX </span><span style="color: #007700">=== </span><span style="color: #DD0000">'dll'</span><span style="color: #007700">) ? </span><span style="color: #DD0000">'php_' </span><span style="color: #007700">: </span><span style="color: #DD0000">''</span><span style="color: #007700">;<br /> </span><span style="color: #0000BB">dl</span><span style="color: #007700">(</span><span style="color: #0000BB">$prefix </span><span style="color: #007700">. </span><span style="color: #DD0000">'sqlite.' </span><span style="color: #007700">. </span><span style="color: #0000BB">PHP_SHLIB_SUFFIX</span><span style="color: #007700">);<br />}<br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> </p> </div> <div class="refsect1 changelog"> <h3 class="title">ChangeLog</h3> <p class="para"> <table class="informaltable"> <colgroup> <thead valign="middle"> <tr valign="middle"> <th colspan="1">Version</th> <th colspan="1">Description</th> </tr> </thead> <tbody valign="middle" class="tbody"> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">5.3.0</td> <td colspan="1" rowspan="1" align="left"> This function now throws an E_DEPRECATED notice on all sapi's except for CLI, CGI and Embed. </td> </tr> </tbody> </colgroup> </table> </p> </div> <div class="refsect1 notes"> <h3 class="title">Notes</h3> <blockquote><p><b class="note">Note</b>: <b>dl()</b> is <em class="emphasis">not</em> supported in multithreaded Web servers. Use the <i>extensions</i> statement in your <var class="filename">php.ini</var> when operating under such an environment. However, the <i>CGI</i> and <i>CLI</i> build are <em class="emphasis">not</em> affected ! <br /> </p></blockquote> <blockquote><p><b class="note">Note</b>: As of PHP 5, the <b>dl()</b> function is deprecated in every SAPI <em class="emphasis">except</em> <acronym title="Command Line Interpreter/Interface">CLI</acronym>. Use <a href="ini.core.html#ini.extension" class="link">Extension Loading Directives</a> method instead. <br /> </p></blockquote> <blockquote><p><b class="note">Note</b>: Since PHP 6 this function is disabled in all SAPIs, except CLI, CGI and embed. <br /> </p></blockquote> <blockquote><p><b class="note">Note</b>: <b>dl()</b> is case sensitive on Unix platforms. <br /> </p></blockquote> <blockquote><p><b class="note">Note</b>: <span class="simpara">This function is disabled when PHP is running in <a href="features.safe-mode.html" class="link">safe mode</a>.</span></p></blockquote> </div> <div class="refsect1 seealso"> <h3 class="title">See Also</h3> <p class="para"> <ul class="simplelist"> <li class="member"><a href="ini.core.html#ini.extension" class="link">Extension Loading Directives</a></li> <li class="member"><a href="function.extension-loaded.html" class="function" rel="rdfs-seeAlso">extension_loaded()</a></li> </ul> </p> </div></div><hr /><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.assert.html">assert</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.extension-loaded.html">extension_loaded</a></div> <div class="up"><a href="ref.info.html">PHP Options/Info 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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