man/tip/nng_sockaddr_abstract.5.html


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---
version: tip
layout: manpage_v2
title: nng_sockaddr_abstract(5)
---
<h1>nng_sockaddr_abstract(5)</h1>
<div class="sect1">
<h2 id="_name">NAME</h2>
<div class="sectionbody">
<div class="paragraph">
<p>nng_sockaddr_abstract - abstract IPC socket address</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">&lt;nng/nng.h&gt;</span>

<span class="tok-k">enum</span><span class="tok-w"> </span><span class="tok-n">sockaddr_family</span><span class="tok-w"> </span><span class="tok-p">{</span>
<span class="tok-w">    </span><span class="tok-n">NNG_AF_ABSTRACT</span><span class="tok-w"> </span><span class="tok-o">=</span><span class="tok-w"> </span><span class="tok-mi">6</span><span class="tok-p">,</span>
<span class="tok-p">};</span>

<span class="tok-k">typedef</span><span class="tok-w"> </span><span class="tok-k">struct</span><span class="tok-w"> </span><span class="tok-p">{</span>
<span class="tok-w">    </span><span class="tok-kt">uint16_t</span><span class="tok-w"> </span><span class="tok-n">sa_family</span><span class="tok-p">;</span>
<span class="tok-w">    </span><span class="tok-kt">uint16_t</span><span class="tok-w"> </span><span class="tok-n">sa_len</span><span class="tok-p">;</span>
<span class="tok-w">    </span><span class="tok-kt">char</span><span class="tok-w">     </span><span class="tok-n">sa_name</span><span class="tok-p">[</span><span class="tok-mi">107</span><span class="tok-p">];</span>
<span class="tok-p">}</span><span class="tok-w"> </span><span class="tok-n">nng_sockaddr_abstract</span><span class="tok-p">;</span></code></pre>
</div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_description">DESCRIPTION</h2>
<div class="sectionbody">
<div class="paragraph">
<p> An <code>nng_sockaddr_abstract</code> is the flavor of <a href="nng_sockaddr.5.html"><code>nng_sockaddr</code></a>
used to represent addresses associated with IPC communication using &#8220;abstract&#8221; sockets.</p>
</div>
<div class="paragraph">
<p>Abstract sockets are only supported on Linux at present.
These sockets have a name that is simply an array of bytes, with no special meaning.
Abstract sockets also have no presence in the file system, do not honor any permissions, and are automatically
cleaned up by the operating system when no longer in use.</p>
</div>
<div class="admonitionblock note">
<table>
<tr>
<td class="icon">
<i class="fa icon-note" title="Note"></i>
</td>
<td class="content">
Support for abstract sockets is a new feature in <em>NNG</em>, and it is only available on Linux.
As such their use is not recommended for portable applications.
</td>
</tr>
</table>
</div>
<div class="paragraph">
<p>The following structure members are present:</p>
</div>
<div class="dlist">
<dl>
<dt class="hdlist1"><code>sa_family</code></dt>
<dd>
<p>This field will always have the value <code>NNG_AF_ABSTRACT</code>.</p>
</dd>
<dt class="hdlist1"><code>sa_len</code></dt>
<dd>
<p>This field provides the name of the length stored in <code>sa_name</code>.</p>
</dd>
<dt class="hdlist1"><code>sa_name</code></dt>
<dd>
<p>This field holds the name of the abstract socket.
The bytes of name can have any value, including zero.</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">
The name does <em>not</em> include the leading <code>NUL</code> byte used on Linux to discriminate between
abstract and path name sockets.
</td>
</tr>
</table>
</div>
<div class="sect2">
<h3 id="_auto_bind">Auto Bind</h3>
<div class="paragraph">
<p>An empty value (<code>sa_len</code> equal to zero) can be used on listening sockets to request the
system allocate a name.
On Linux systems, this will result in a name with either 5 or 8 hexadecimal ASCII characters.
The name chosen can be obtained by retrieving the <code>NNG_OPT_LOCADDR</code> option on the listening entity.</p>
</div>
<div class="admonitionblock note">
<table>
<tr>
<td class="icon">
<i class="fa icon-note" title="Note"></i>
</td>
<td class="content">
Because a zero length name is used to indicate auto bind be used, it is impossible to specify
an actual empty name.  This name are not supported by <em>NNG</em>, although the underlying system can support it.
The use of that name is inadvisable anyway.
</td>
</tr>
</table>
</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_sockaddr.5.html">nng_sockaddr(5)</a>,
<a href="nng_ipc.7.html">nng_ipc(7)</a>
<a href="nng.7.html">nng(7)</a></p>
</div>
</div>
</div>