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<h1 class="refname">socket_listen</h1>
<p class="verinfo">(PHP 4 >= 4.1.0, PHP 5)</p><p class="refpurpose"><span class="refname">socket_listen</span> — <span class="dc-title">Listens for a connection on a socket</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.socket-listen-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type">bool</span> <span class="methodname"><strong>socket_listen</strong></span>
( <span class="methodparam"><span class="type">resource</span> <code class="parameter">$socket</code></span>
[, <span class="methodparam"><span class="type">int</span> <code class="parameter">$backlog</code><span class="initializer"> = 0</span></span>
] )</div>
<p class="para rdfs-comment">
After the socket <em><code class="parameter">socket</code></em> has been created
using <span class="function"><a href="function.socket-create.html" class="function">socket_create()</a></span> and bound to a name with
<span class="function"><a href="function.socket-bind.html" class="function">socket_bind()</a></span>, it may be told to listen for incoming
connections on <em><code class="parameter">socket</code></em>.
</p>
<p class="para">
<span class="function"><strong>socket_listen()</strong></span> is applicable only to sockets of
type <strong><code>SOCK_STREAM</code></strong> or
<strong><code>SOCK_SEQPACKET</code></strong>.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.socket-listen-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term"><em><code class="parameter">socket</code></em></span>
<dd>
<p class="para">
A valid socket resource created with <span class="function"><a href="function.socket-create.html" class="function">socket_create()</a></span>.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">backlog</code></em></span>
<dd>
<p class="para">
A maximum of <em><code class="parameter">backlog</code></em> incoming connections will be
queued for processing. If a connection request arrives with the queue
full the client may receive an error with an indication of
<em>ECONNREFUSED</em>, or, if the underlying protocol supports
retransmission, the request may be ignored so that retries may succeed.
</p>
<blockquote class="note"><p><strong class="note">Note</strong>:
<p class="para">
The maximum number passed to the <em><code class="parameter">backlog</code></em>
parameter highly depends on the underlying platform. On Linux, it is
silently truncated to <strong><code>SOMAXCONN</code></strong>. On win32, if
passed <strong><code>SOMAXCONN</code></strong>, the underlying service provider
responsible for the socket will set the backlog to a maximum
<em class="emphasis">reasonable</em> value. There is no standard provision to
find out the actual backlog value on this platform.
</p>
</p></blockquote>
</dd>
</dt>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.socket-listen-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns <strong><code>TRUE</code></strong> on success or <strong><code>FALSE</code></strong> on failure. The error code can be retrieved with
<span class="function"><a href="function.socket-last-error.html" class="function">socket_last_error()</a></span>. This code may be passed to
<span class="function"><a href="function.socket-strerror.html" class="function">socket_strerror()</a></span> to get a textual explanation of the
error.
</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.socket-listen-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"> <span class="function"><a href="function.socket-accept.html" class="function" rel="rdfs-seeAlso">socket_accept()</a> - Accepts a connection on a socket</span></li>
<li class="member"> <span class="function"><a href="function.socket-bind.html" class="function" rel="rdfs-seeAlso">socket_bind()</a> - Binds a name to a socket</span></li>
<li class="member"> <span class="function"><a href="function.socket-connect.html" class="function" rel="rdfs-seeAlso">socket_connect()</a> - Initiates a connection on a socket</span></li>
<li class="member"> <span class="function"><a href="function.socket-create.html" class="function" rel="rdfs-seeAlso">socket_create()</a> - Create a socket (endpoint for communication)</span></li>
<li class="member"> <span class="function"><a href="function.socket-strerror.html" class="function" rel="rdfs-seeAlso">socket_strerror()</a> - Return a string describing a socket error</span></li>
</ul>
</p>
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