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<title>Sets a user-defined exception handler function</title>
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<h1 class="refname">set_exception_handler</h1>
<p class="verinfo">(PHP 5)</p><p class="refpurpose"><span class="refname">set_exception_handler</span> — <span class="dc-title">
Sets a user-defined exception handler function
</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.set-exception-handler-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type"><a href="language.types.callable.html" class="type callable">callable</a></span> <span class="methodname"><strong>set_exception_handler</strong></span>
( <span class="methodparam"><span class="type"><a href="language.types.callable.html" class="type callable">callable</a></span> <code class="parameter">$exception_handler</code></span>
)</div>
<p class="para rdfs-comment">
Sets the default exception handler if an exception is not caught within a
try/catch block. Execution will stop after the
<em><code class="parameter">exception_handler</code></em> is called.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.set-exception-handler-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term"><em><code class="parameter">exception_handler</code></em></span>
<dd>
<p class="para">
Name of the function to be called when an uncaught exception occurs.
This function must be defined before calling
<span class="function"><strong>set_exception_handler()</strong></span>. This handler function
needs to accept one parameter, which will be the exception object that
was thrown. This is the handler signature:
</p>
<p class="para">
<div class="methodsynopsis dc-description">
<span class="type"><span class="type void">void</span></span> <span class="methodname"><span class="replaceable">handler</span></span>
( <span class="methodparam"><span class="type"><a href="class.exception.html" class="type Exception">Exception</a></span> <code class="parameter">$ex</code></span>
)</div>
</p>
<p class="para">
<strong><code>NULL</code></strong> may be passed instead, to reset this handler to its default state.
</p>
</dd>
</dt>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.set-exception-handler-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns the name of the previously defined exception handler, or <strong><code>NULL</code></strong> on error. If
no previous handler was defined, <strong><code>NULL</code></strong> is also returned.
</p>
</div>
<div class="refsect1 changelog" id="refsect1-function.set-exception-handler-changelog">
<h3 class="title">Changelog</h3>
<p class="para">
<table class="doctable informaltable">
<thead>
<tr>
<th>Version</th>
<th>Description</th>
</tr>
</thead>
<tbody class="tbody">
<tr>
<td>5.5.0</td>
<td>
Previously, if <strong><code>NULL</code></strong> was passed then this function returned <strong><code>TRUE</code></strong>.
It returns the previous handler since PHP 5.5.0.
</td>
</tr>
</tbody>
</table>
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.set-exception-handler-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-457">
<p><strong>Example #1 <span class="function"><strong>set_exception_handler()</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: #007700">function </span><span style="color: #0000BB">exception_handler</span><span style="color: #007700">(</span><span style="color: #0000BB">$exception</span><span style="color: #007700">) {<br /> echo </span><span style="color: #DD0000">"Uncaught exception: " </span><span style="color: #007700">, </span><span style="color: #0000BB">$exception</span><span style="color: #007700">-></span><span style="color: #0000BB">getMessage</span><span style="color: #007700">(), </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />}<br /><br /></span><span style="color: #0000BB">set_exception_handler</span><span style="color: #007700">(</span><span style="color: #DD0000">'exception_handler'</span><span style="color: #007700">);<br /><br />throw new </span><span style="color: #0000BB">Exception</span><span style="color: #007700">(</span><span style="color: #DD0000">'Uncaught Exception'</span><span style="color: #007700">);<br />echo </span><span style="color: #DD0000">"Not Executed\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.set-exception-handler-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"> <span class="function"><a href="function.restore-exception-handler.html" class="function" rel="rdfs-seeAlso">restore_exception_handler()</a> - Restores the previously defined exception handler function</span></li>
<li class="member"> <span class="function"><a href="function.restore-error-handler.html" class="function" rel="rdfs-seeAlso">restore_error_handler()</a> - Restores the previous error handler function</span></li>
<li class="member"> <span class="function"><a href="function.error-reporting.html" class="function" rel="rdfs-seeAlso">error_reporting()</a> - Sets which PHP errors are reported</span></li>
<li class="member">information about the <a href="language.pseudo-types.html#language.types.callback" class="link">callback</a> type</li>
<li class="member"><a href="language.exceptions.html" class="link">PHP 5 Exceptions</a></li>
</ul>
</p>
</div>
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