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<title>Checks if the interface has been defined</title>
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<h1 class="refname">interface_exists</h1>
<p class="verinfo">(PHP 5 >= 5.0.2)</p><p class="refpurpose"><span class="refname">interface_exists</span> — <span class="dc-title">Checks if the interface has been defined</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.interface-exists-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type">bool</span> <span class="methodname"><strong>interface_exists</strong></span>
( <span class="methodparam"><span class="type">string</span> <code class="parameter">$interface_name</code></span>
[, <span class="methodparam"><span class="type">bool</span> <code class="parameter">$autoload</code><span class="initializer"> = true</span></span>
] )</div>
<p class="para rdfs-comment">
Checks if the given interface has been defined.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.interface-exists-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term"><em><code class="parameter">interface_name</code></em></span>
<dd>
<p class="para">
The interface name
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">autoload</code></em></span>
<dd>
<p class="para">
Whether to call <a href="language.oop5.autoload.html" class="link">__autoload</a> or not by default.
</p>
</dd>
</dt>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.interface-exists-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns <strong><code>TRUE</code></strong> if the interface given by
<em><code class="parameter">interface_name</code></em> has been defined, <strong><code>FALSE</code></strong> otherwise.
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.interface-exists-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-5057">
<p><strong>Example #1 <span class="function"><strong>interface_exists()</strong></span> example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">// Check the interface exists before trying to use it<br /></span><span style="color: #007700">if (</span><span style="color: #0000BB">interface_exists</span><span style="color: #007700">(</span><span style="color: #DD0000">'MyInterface'</span><span style="color: #007700">)) {<br /> class </span><span style="color: #0000BB">MyClass </span><span style="color: #007700">implements </span><span style="color: #0000BB">MyInterface<br /> </span><span style="color: #007700">{<br /> </span><span style="color: #FF8000">// Methods<br /> </span><span style="color: #007700">}<br />}<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.interface-exists-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"> <span class="function"><a href="function.get-declared-interfaces.html" class="function" rel="rdfs-seeAlso">get_declared_interfaces()</a> - Returns an array of all declared interfaces</span></li>
<li class="member"> <span class="function"><a href="function.class-implements.html" class="function" rel="rdfs-seeAlso">class_implements()</a> - Return the interfaces which are implemented by the given class</span></li>
<li class="member"> <span class="function"><a href="function.class-exists.html" class="function" rel="rdfs-seeAlso">class_exists()</a> - Checks if the class has been defined</span></li>
</ul>
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