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<title>Free all session variables</title>
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<h1 class="refname">session_unset</h1>
<p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">session_unset</span> — <span class="dc-title">Free all session variables</span></p>
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<div class="refsect1 description" id="refsect1-function.session-unset-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type"><span class="type void">void</span></span> <span class="methodname"><strong>session_unset</strong></span>
( <span class="methodparam">void</span>
)</div>
<p class="para rdfs-comment">
The <span class="function"><strong>session_unset()</strong></span> function frees all session variables
currently registered.
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.session-unset-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
No value is returned.
</p>
</div>
<div class="refsect1 notes" id="refsect1-function.session-unset-notes">
<h3 class="title">Notes</h3>
<blockquote class="note"><p><strong class="note">Note</strong>:
<p class="para">
If <var class="varname"><var class="varname"><a href="reserved.variables.session.html" class="classname">$_SESSION</a></var></var> (or <var class="varname"><var class="varname">$HTTP_SESSION_VARS</var></var>
for PHP 4.0.6 or less) is used, use <span class="function"><a href="function.unset.html" class="function">unset()</a></span> to
unregister a session variable, i.e.
<em>unset ($_SESSION['varname']);</em>.
</p>
</p></blockquote>
<div class="caution"><strong class="caution">Caution</strong>
<p class="para">
Do NOT unset the whole <var class="varname"><var class="varname"><a href="reserved.variables.session.html" class="classname">$_SESSION</a></var></var> with
<em>unset($_SESSION)</em> as this will disable the registering
of session variables through the <var class="varname"><var class="varname"><a href="reserved.variables.session.html" class="classname">$_SESSION</a></var></var> superglobal.
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