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---
version: tip
layout: manpage_v2
title: nng_push(7)
---
<h1>nng_push(7)</h1>
<div class="sect1">
<h2 id="_name">NAME</h2>
<div class="sectionbody">
<div class="paragraph">
<p>nng_push - push protocol</p>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_synopsis">SYNOPSIS</h2>
<div class="sectionbody">
<div class="listingblock">
<div class="content">
<pre class="pygments highlight"><code data-lang="c"><span></span><span class="tok-cp">#include</span><span class="tok-w"> </span><span class="tok-cpf"><nng/protocol/pipeline0/push.h></span></code></pre>
</div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_description">DESCRIPTION</h2>
<div class="sectionbody">
<div class="paragraph">
<p>
The <em>push</em> protocol is one half of a pipeline pattern.
The other side is the <a href="nng_pull.7.html"><em>pull</em></a> protocol.</p>
</div>
<div class="paragraph">
<p>In the pipeline pattern, pushers distribute messages to pullers.
Each message sent by a pusher will be sent to one of its peer pullers,
chosen in a round-robin fashion
from the set of connected peers available for receiving.
This property makes this pattern useful in load-balancing scenarios.</p>
</div>
<div class="sect2">
<h3 id="_socket_operations">Socket Operations</h3>
<div class="paragraph">
<p>The <a href="nng_push_open.3.html"><code>nng_push0_open()</code></a> call creates a pusher socket.
This socket may be used to send messages, but is unable to receive them.
Attempts to receive messages will result in <code>NNG_ENOTSUP</code>.</p>
</div>
<div class="paragraph">
<p>Send operations will observe flow control (back-pressure), so that
only peers capable of accepting a message will be considered.
If no peer is available to receive a message, then the send operation will
wait until one is available, or the operation times out.</p>
</div>
<div class="admonitionblock note">
<table>
<tr>
<td class="icon">
<i class="fa icon-note" title="Note"></i>
</td>
<td class="content">
Although the pipeline protocol honors flow control, and attempts
to avoid dropping messages, no guarantee of delivery is made.
Furthermore, as there is no capability for message acknowledgment,
applications that need reliable delivery are encouraged to consider the
<a href="nng_req.7.html"><em>req</em></a> protocol instead.
</td>
</tr>
</table>
</div>
</div>
<div class="sect2">
<h3 id="_protocol_versions">Protocol Versions</h3>
<div class="paragraph">
<p>Only version 0 of this protocol is supported.
(At the time of writing, no other versions of this protocol have been defined.)</p>
</div>
</div>
<div class="sect2">
<h3 id="_protocol_options">Protocol Options</h3>
<div class="dlist">
<dl>
<dt class="hdlist1"><a href="nng_options.5.html#NNG_OPT_SENDBUF"><code>NNG_OPT_SENDBUF</code></a></dt>
<dd>
<p>(<code>int</code>, 0 - 8192)
Normally this is set to zero, indicating that send operations are unbuffered.
In unbuffered operation, send operations will wait until a suitable peer is available to receive the message.
If this is set to a positive value (up to 8192), then an intermediate buffer is
provided for the socket with the specified depth (in messages).</p>
</dd>
</dl>
</div>
<div class="admonitionblock note">
<table>
<tr>
<td class="icon">
<i class="fa icon-note" title="Note"></i>
</td>
<td class="content">
Transport layer buffering may occur in addition to any socket
buffer determined by this option.
</td>
</tr>
</table>
</div>
</div>
<div class="sect2">
<h3 id="_protocol_headers">Protocol Headers</h3>
<div class="paragraph">
<p>The <em>push</em> protocol has no protocol-specific headers.</p>
</div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_see_also">SEE ALSO</h2>
<div class="sectionbody">
<div class="paragraph text-left">
<p><a href="nng_push_open.3.html">nng_push(3)</a>,
<a href="nng_pull.7.html">nng_pull(7)</a>,
<a href="nng_req.7.html">nng_req(7)</a>,
<a href="nng.7.html">nng(7)</a></p>
</div>
</div>
</div>
|
