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<title>Finds whether a variable is NULL</title>
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<h1 class="refname">is_null</h1>
<p class="verinfo">(PHP 4 >= 4.0.4, PHP 5)</p><p class="refpurpose"><span class="refname">is_null</span> — <span class="dc-title">
Finds whether a variable is <strong><code>NULL</code></strong>
</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.is-null-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type">bool</span> <span class="methodname"><strong>is_null</strong></span>
( <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$var</code></span>
)</div>
<p class="para rdfs-comment">
Finds whether the given variable is <strong><code>NULL</code></strong>.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.is-null-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term"><em><code class="parameter">var</code></em></span>
<dd>
<p class="para">
The variable being evaluated.
</p>
</dd>
</dt>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.is-null-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns <strong><code>TRUE</code></strong> if <em><code class="parameter">var</code></em> is <span class="type"><a href="language.types.null.html" class="type null">null</a></span>, <strong><code>FALSE</code></strong>
otherwise.
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.is-null-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-5261">
<p><strong>Example #1 <span class="function"><strong>is_null()</strong></span> example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br />error_reporting</span><span style="color: #007700">(</span><span style="color: #0000BB">E_ALL</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$foo </span><span style="color: #007700">= </span><span style="color: #0000BB">NULL</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">is_null</span><span style="color: #007700">(</span><span style="color: #0000BB">$inexistent</span><span style="color: #007700">), </span><span style="color: #0000BB">is_null</span><span style="color: #007700">(</span><span style="color: #0000BB">$foo</span><span style="color: #007700">));<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents screen">
<div class="cdata"><pre>
Notice: Undefined variable: inexistent in ...
bool(true)
bool(true)
</pre></div>
</div>
</div>
</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.is-null-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member">The <a href="language.types.null.html#language.types.null.syntax" class="link"><strong><code>NULL</code></strong></a> type</li>
<li class="member"> <span class="function"><a href="function.isset.html" class="function" rel="rdfs-seeAlso">isset()</a> - Determine if a variable is set and is not NULL</span></li>
<li class="member"> <span class="function"><a href="function.is-bool.html" class="function" rel="rdfs-seeAlso">is_bool()</a> - Finds out whether a variable is a boolean</span></li>
<li class="member"> <span class="function"><a href="function.is-numeric.html" class="function" rel="rdfs-seeAlso">is_numeric()</a> - Finds whether a variable is a number or a numeric string</span></li>
<li class="member"> <span class="function"><a href="function.is-float.html" class="function" rel="rdfs-seeAlso">is_float()</a> - Finds whether the type of a variable is float</span></li>
<li class="member"> <span class="function"><a href="function.is-int.html" class="function" rel="rdfs-seeAlso">is_int()</a> - Find whether the type of a variable is integer</span></li>
<li class="member"> <span class="function"><a href="function.is-string.html" class="function" rel="rdfs-seeAlso">is_string()</a> - Find whether the type of a variable is string</span></li>
<li class="member"> <span class="function"><a href="function.is-object.html" class="function" rel="rdfs-seeAlso">is_object()</a> - Finds whether a variable is an object</span></li>
<li class="member"> <span class="function"><a href="function.is-array.html" class="function" rel="rdfs-seeAlso">is_array()</a> - Finds whether a variable is an array</span></li>
</ul>
</p>
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