<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>Event callbacks</title>
</head>
<body><div class="manualnavbar" style="text-align: center;">
<div class="prev" style="text-align: left; float: left;"><a href="event.persistence.html">About event persistence</a></div>
<div class="next" style="text-align: right; float: right;"><a href="event.constructing.signal.events.html">Constructing signal events</a></div>
<div class="up"><a href="book.event.html">Event</a></div>
<div class="home"><a href="index.html">PHP Manual</a></div>
</div><hr /><div id="event.callbacks" class="chapter">
<h1>Event callbacks</h1>
<p class="para">
If a callback is registered for an event, it will be called when the event
becomes active. To associate a callback with event one can pass a
<span class="type"><a href="language.types.callable.html" class="type callable">callable</a></span>
to whether
<span class="methodname"><a href="event.construct.html" class="methodname">Event::__construct()</a></span>
, or
<span class="methodname"><a href="event.set.html" class="methodname">Event::set()</a></span>
, or one of the factory methods like
<span class="methodname"><a href="event.timer.html" class="methodname">Event::timer()</a></span>
.
</p>
<p class="para">
An event callback should match the following prototype:
</p>
<div class="methodsynopsis dc-description">
<span class="type"><span class="type void">void</span></span>
<span class="methodname"><strong>callback</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">$fd</code>
<span class="initializer"> = <strong><code>NULL</code></strong></span>
</span>
[, <span class="methodparam">
<span class="type">int</span>
<code class="parameter">$what</code>
</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">$arg</code>
<span class="initializer"> = <strong><code>NULL</code></strong></span>
</span>
]]] )</div>
<p class="para">
<dl>
<dt>
<span class="term">
<em><code class="parameter">fd</code></em>
</span>
<dd>
<p class="para">
The file descriptor, stream resource or socket associated with the
event. For signal event
<em><code class="parameter">fd</code></em>
is equal to the signal number.
</p>
</dd>
</dt>
<dt>
<span class="term">
<em><code class="parameter">what</code></em>
</span>
<dd>
<p class="para">
Bit mask of
<em class="emphasis">all</em>
events triggered.
</p>
</dd>
</dt>
<dt>
<span class="term">
<em><code class="parameter">arg</code></em>
</span>
<dd>
<p class="para">
User custom data.
</p>
</dd>
</dt>
</dl>
</p>
<p class="para">
<span class="methodname"><a href="event.timer.html" class="methodname">Event::timer()</a></span>
expects the callback to match the following prototype:
</p>
<div class="methodsynopsis dc-description">
<span class="type"><span class="type void">void</span></span>
<span class="methodname"><strong>callback</strong></span>
([ <span class="methodparam">
<span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span>
<code class="parameter">$arg</code>
<span class="initializer"> = <strong><code>NULL</code></strong></span>
</span>
] )</div>
<p class="para">
<dl>
<dt>
<span class="term">
<em><code class="parameter">arg</code></em>
</span>
<dd>
<p class="para">
User custom data.
</p>
</dd>
</dt>
</dl>
</p>
<p class="para">
<span class="methodname"><a href="event.signal.html" class="methodname">Event::signal()</a></span>
expects the callback to match the following prototype:
</p>
<div class="methodsynopsis dc-description">
<span class="type"><span class="type void">void</span></span>
<span class="methodname"><strong>callback</strong></span>
([ <span class="methodparam">
<span class="type">int</span>
<code class="parameter">$signum</code>
</span>
[, <span class="methodparam">
<span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span>
<code class="parameter">$arg</code>
<span class="initializer"> = <strong><code>NULL</code></strong></span>
</span>
]] )</div>
<p class="para">
<dl>
<dt>
<span class="term">
<em><code class="parameter">signum</code></em>
</span>
<dd>
<p class="para">
The number of the triggered signal(e.g.
<strong><code>SIGTERM</code></strong>
).
</p>
</dd>
</dt>
<dt>
<span class="term">
<em><code class="parameter">arg</code></em>
</span>
<dd>
<p class="para">
User custom data.
</p>
</dd>
</dt>
</dl>
</p>
</div>
<hr /><div class="manualnavbar" style="text-align: center;">
<div class="prev" style="text-align: left; float: left;"><a href="event.persistence.html">About event persistence</a></div>
<div class="next" style="text-align: right; float: right;"><a href="event.constructing.signal.events.html">Constructing signal events</a></div>
<div class="up"><a href="book.event.html">Event</a></div>
<div class="home"><a href="index.html">PHP Manual</a></div>
</div></body></html>
