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<h1 class="lined-header"><span>ranch:start_listener(3)</span></h1>
<h2 id="_name">Name</h2>
<p>ranch:start_listener - Start a listener</p>
<h2 id="_description">Description</h2>
<div class="listingblock"><div class="content"><!-- Generator: GNU source-highlight 3.1.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><b><font color="#000000">start_listener</font></b>(<font color="#009900">Ref</font> <font color="#990000">::</font> <b><font color="#000000">ranch_ref</font></b>(),
<font color="#009900">Transport</font> <font color="#990000">::</font> <b><font color="#000000">module</font></b>(),
<font color="#009900">TransOpts</font> <font color="#990000">::</font> <b><font color="#000000">ranch:opts</font></b>(),
<font color="#009900">Protocol</font> <font color="#990000">::</font> <b><font color="#000000">module</font></b>(),
<font color="#009900">ProtoOpts</font> <font color="#990000">::</font> <b><font color="#000000">any</font></b>())
<font color="#990000">-></font> {<font color="#FF6600">ok</font>, <font color="#009900">ListenerPid</font> <font color="#990000">::</font> <b><font color="#000080">pid</font></b>()}
| {<font color="#FF6600">error</font>, <b><font color="#000000">any</font></b>()}</tt></pre>
</div></div>
<p>Start a listener.</p>
<p>A listener is a set of processes that accepts and manages connections using the given transport and protocol modules.</p>
<h2 id="_arguments">Arguments</h2>
<dl><dt>Ref</dt>
<dd><p>The listener name is used to refer to this listener in future calls, for example when stopping it or when updating the configuration.</p>
<p>It can be any Erlang term. An atom is generally good enough, for example <code>api</code>, <code>my_app_clear</code> or <code>my_app_tls</code>.</p>
</dd>
<dt>Transport</dt>
<dd><p>The transport module that will be used by Ranch to accept connections and that will be passed to the protocol module along with the socket.</p>
<p>The interface of the transport module is documented in the <a href="../ranch_transport">ranch_transport(3)</a> manual.</p>
</dd>
<dt>TransportOpts</dt>
<dd><p>Transport options include the Ranch-specific options and the socket options. The listener's port number must be defined in the socket options.</p>
<p>Socket options may be given directly if there are no Ranch-specific options.</p>
<p>The available options for the built-in Ranch transports are documented in the <a href="../ranch_tcp">ranch_tcp(3)</a> and <a href="../ranch_ssl">ranch_ssl(3)</a> manuals.</p>
</dd>
<dt>Protocol</dt>
<dd><p>The protocol module that will be used by Ranch after the connection has been accepted.</p>
<p>The interface of the protocol module is documented in the <a href="../ranch_protocol">ranch_protocol(3)</a> manual.</p>
</dd>
<dt>ProtocolOpts</dt>
<dd><p>The protocol options given when calling the protocol module. Please consult the documentation of the protocol module you are using for more details.</p>
</dd>
</dl>
<h2 id="_return_value">Return value</h2>
<p>An ok tuple is returned on success. It contains the pid of the top-level supervisor for the listener.</p>
<p>An error tuple is returned on error. The error reason may be any Erlang term.</p>
<p>A common error is <code>eaddrinuse</code>. It indicates that the port configured for Ranch is already in use.</p>
<h2 id="_changelog">Changelog</h2>
<ul><li><strong>1.4</strong>: The <code>NumAcceptors</code> argument was moved to the transport options.
</li>
</ul>
<h2 id="_examples">Examples</h2>
<div class="listingblock"><div class="title">Start a listener</div>
<div class="content"><!-- Generator: GNU source-highlight 3.1.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt>{<font color="#FF6600">ok</font>, <font color="#990000">_</font>} <font color="#990000">=</font> <b><font color="#000000">ranch:start_listener</font></b>(<font color="#FF6600">example</font>,
<font color="#FF6600">ranch_tcp</font>, [{<font color="#FF6600">port</font>, <font color="#993399">8080</font>}],
<font color="#FF6600">cowboy_http2</font>, #{}
)<font color="#990000">.</font></tt></pre>
</div></div>
<div class="listingblock"><div class="title">Start a listener with Ranch-specific options</div>
<div class="content"><!-- Generator: GNU source-highlight 3.1.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt>{<font color="#FF6600">ok</font>, <font color="#990000">_</font>} <font color="#990000">=</font> <b><font color="#000000">ranch:start_listener</font></b>(<font color="#FF6600">example</font>,
<font color="#FF6600">ranch_tcp</font>, #{
<font color="#0000FF">num_acceptors</font> <font color="#990000">=></font> <font color="#993399">75</font>,
<font color="#0000FF">socket_opts</font> <font color="#990000">=></font> [{<font color="#FF6600">port</font>, <font color="#993399">8080</font>}]
},
<font color="#FF6600">cowboy_http2</font>, #{}
)<font color="#990000">.</font></tt></pre>
</div></div>
<div class="listingblock"><div class="title">Start a listener on a random port</div>
<div class="content"><!-- Generator: GNU source-highlight 3.1.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><font color="#009900">Ref</font> <font color="#990000">=</font> <font color="#FF6600">example</font>,
{<font color="#FF6600">ok</font>, <font color="#990000">_</font>} <font color="#990000">=</font> <b><font color="#000000">ranch:start_listener</font></b>(<font color="#009900">Ref</font>,
<font color="#FF6600">ranch_tcp</font>, #{},
<font color="#FF6600">cowboy_http2</font>, #{}
),
<font color="#009900">Port</font> <font color="#990000">=</font> <b><font color="#000000">ranch:get_port</font></b>(<font color="#009900">Ref</font>)<font color="#990000">.</font></tt></pre>
</div></div>
<h2 id="_see_also">See also</h2>
<p><a href="../ranch.stop_listener">ranch:stop_listener(3)</a>, <a href="../ranch.child_spec">ranch:child_spec(3)</a>, <a href="../ranch">ranch(3)</a>, <a href="../ranch_tcp">ranch_tcp(3)</a>, <a href="../ranch_ssl">ranch_ssl(3)</a>, <a href="../ranch_transport">ranch_transport(3)</a>, <a href="../ranch_protocol">ranch_protocol(3)</a></p>
</div>
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<h3>
Ranch
1.7
Function Reference
</h3>
<ul>
<li><a href="/docs/en/ranch/1.7/guide">User Guide</a></li>
<li><a href="/docs/en/ranch/1.7/manual">Function Reference</a></li>
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<h4>Version select</h4>
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