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<h1>About buffer event callbacks</h1>
<p class="para">
An object of
<a href="class.eventbufferevent.html" class="classname">EventBufferEvent</a>
class represents a
<em class="emphasis">buffer event</em>
. The asynchronous nature of I/O performed by Libevent implies that a
socket(or other kind of file descriptor) is not always available. Event
invokes corresponding callbacks when the resource becomes available for
reading or writing, or when some event occurs(e.g. error, "end of line"
etc.).
</p>
<p class="para">
Read and write callbacks 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="class.eventbufferevent.html" class="type EventBufferEvent">EventBufferEvent</a></span>
<code class="parameter">$bev</code>
<span class="initializer"> = <strong><code>NULL</code></strong></span>
</span>
[, <span class="methodparam">
<span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span>
<code class="parameter">$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">bev</code></em>
</span>
<dd>
<p class="para">
Associated
<a href="class.eventbufferevent.html" class="classname">EventBufferEvent</a>
object.
</p>
</dd>
</dt>
<dt>
<span class="term">
<em><code class="parameter">arg</code></em>
</span>
<dd>
<p class="para">
Custom variable attached to all callbacks via
<span class="methodname"><a href="eventbufferevent.construct.html" class="methodname">EventBufferEvent::__construct()</a></span>
, or
<span class="methodname"><a href="eventbufferevent.setcallbacks.html" class="methodname">EventBufferEvent::setCallbacks()</a></span>
.
</p>
</dd>
</dt>
</dl>
</p>
<p class="para">
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="class.eventbufferevent.html" class="type EventBufferEvent">EventBufferEvent</a></span>
<code class="parameter">$bev</code>
<span class="initializer"> = <strong><code>NULL</code></strong></span>
</span>
[, <span class="methodparam">
<span class="type">int</span>
<code class="parameter">$events</code>
<span class="initializer"> = 0</span>
</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">bev</code></em>
</span>
<dd>
<p class="para">
Associated
<a href="class.eventbufferevent.html" class="classname">EventBufferEvent</a>
object.
</p>
</dd>
</dt>
<dt>
<span class="term">
<em><code class="parameter">events</code></em>
</span>
<dd>
<p class="para">
Bit mask of events:
<strong><code>EventBufferEvent::READING</code></strong>
,
<strong><code>EventBufferEvent::WRITING</code></strong>
,
<strong><code>EventBufferEvent::EOL</code></strong>
,
<strong><code>EventBufferEvent::ERROR</code></strong>
and
<strong><code>EventBufferEvent::TIMEOUT</code></strong>
. See
<a href="class.eventbufferevent.html#eventbufferevent.constants" class="link">EventBufferEvent constants</a>
</p>
</dd>
</dt>
<dt>
<span class="term">
<em><code class="parameter">arg</code></em>
</span>
<dd>
<p class="para">
Custom variable attached to all callbacks via
<span class="methodname"><a href="eventbufferevent.construct.html" class="methodname">EventBufferEvent::__construct()</a></span>
, or
<span class="methodname"><a href="eventbufferevent.setcallbacks.html" class="methodname">EventBufferEvent::setCallbacks()</a></span>
.
</p>
</dd>
</dt>
</dl>
</p>
</div>
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