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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>Defines a named constant</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.constant.html">constant</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.defined.html">defined</a></div> <div class="up"><a href="ref.misc.html">Misc. Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div><hr /><div id="function.define" class="refentry"> <div class="refnamediv"> <h1 class="refname">define</h1> <p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">define</span> — <span class="dc-title">Defines a named constant</span></p> </div> <div class="refsect1 description"> <h3 class="title">Description</h3> <div class="methodsynopsis dc-description"> <span class="type">bool</span> <span class="methodname"><b><b>define</b></b></span> ( <span class="methodparam"><span class="type">string</span> <tt class="parameter">$name</tt></span> , <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <tt class="parameter">$value</tt></span> [, <span class="methodparam"><span class="type">bool</span> <tt class="parameter">$case_insensitive</tt></span> ] )</div> <p class="para rdfs-comment"> Defines a named constant at runtime. </p> </div> <div class="refsect1 parameters"> <h3 class="title">Parameters</h3> <p class="para"> <dl> <dt> <span class="term"><i><tt class="parameter">name</tt></i></span> <dd> <p class="para"> The name of the constant. </p> </dd> </dt> <dt> <span class="term"><i><tt class="parameter">value</tt></i></span> <dd> <p class="para"> The value of the constant; only scalar and <a href="language.types.null.html" class="type null">null</a> values are allowed. Scalar values are <a href="language.types.integer.html" class="type integer">integer</a>, <a href="language.types.float.html" class="type float">float</a>, <a href="language.types.string.html" class="type string">string</a> or <a href="language.types.boolean.html" class="type boolean">boolean</a> values. </p> </dd> </dt> <dt> <span class="term"><i><tt class="parameter">case_insensitive</tt></i></span> <dd> <p class="para"> If set to <b><tt>TRUE</tt></b>, the constant will be defined case-insensitive. The default behaviour is case-sensitive; i.e. <i>CONSTANT</i> and <i>Constant</i> represent different values. </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. </p> </div> <div class="refsect1 examples"> <h3 class="title">Examples</h3> <p class="para"> <div class="example"> <p><b>Example #1 Defining Constants</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br />define</span><span style="color: #007700">(</span><span style="color: #DD0000">"CONSTANT"</span><span style="color: #007700">, </span><span style="color: #DD0000">"Hello world."</span><span style="color: #007700">);<br />echo </span><span style="color: #0000BB">CONSTANT</span><span style="color: #007700">; </span><span style="color: #FF8000">// outputs "Hello world."<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">Constant</span><span style="color: #007700">; </span><span style="color: #FF8000">// outputs "Constant" and issues a notice.<br /><br /></span><span style="color: #0000BB">define</span><span style="color: #007700">(</span><span style="color: #DD0000">"GREETING"</span><span style="color: #007700">, </span><span style="color: #DD0000">"Hello you."</span><span style="color: #007700">, </span><span style="color: #0000BB">true</span><span style="color: #007700">);<br />echo </span><span style="color: #0000BB">GREETING</span><span style="color: #007700">; </span><span style="color: #FF8000">// outputs "Hello you."<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">Greeting</span><span style="color: #007700">; </span><span style="color: #FF8000">// outputs "Hello you."<br /><br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> </p> </div> <div class="refsect1 seealso"> <h3 class="title">See Also</h3> <p class="para"> <ul class="simplelist"> <li class="member"><a href="function.defined.html" class="function" rel="rdfs-seeAlso">defined()</a></li> <li class="member"><a href="function.constant.html" class="function" rel="rdfs-seeAlso">constant()</a></li> <li class="member">The section on <a href="language.constants.html" class="link">Constants</a></li> </ul> </p> </div></div><hr /><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.constant.html">constant</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.defined.html">defined</a></div> <div class="up"><a href="ref.misc.html">Misc. 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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