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<h1>luaposix 33.3.0</h1>
<ul>
<li><a href="../index.html">Index</a></li>
</ul>
<h2>Contents</h2>
<ul>
<li><a href="#Functions">Functions</a></li>
<li><a href="#Tables">Tables</a></li>
<li><a href="#Constants">Constants </a></li>
</ul>
<h2>Modules</h2>
<ul class="$(kind=='Topics' and '' or 'nowrap'">
<li><a href="../modules/posix.html">posix</a></li>
<li><a href="../modules/posix.ctype.html">posix.ctype</a></li>
<li><a href="../modules/posix.curses.html">posix.curses</a></li>
<li><a href="../modules/posix.dirent.html">posix.dirent</a></li>
<li><a href="../modules/posix.errno.html">posix.errno</a></li>
<li><a href="../modules/posix.fcntl.html">posix.fcntl</a></li>
<li><a href="../modules/posix.fnmatch.html">posix.fnmatch</a></li>
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<li><a href="../modules/posix.libgen.html">posix.libgen</a></li>
<li><a href="../modules/posix.poll.html">posix.poll</a></li>
<li><a href="../modules/posix.pwd.html">posix.pwd</a></li>
<li><a href="../modules/posix.sched.html">posix.sched</a></li>
<li><a href="../modules/posix.signal.html">posix.signal</a></li>
<li><a href="../modules/posix.stdio.html">posix.stdio</a></li>
<li><a href="../modules/posix.stdlib.html">posix.stdlib</a></li>
<li><a href="../modules/posix.sys.msg.html">posix.sys.msg</a></li>
<li><a href="../modules/posix.sys.resource.html">posix.sys.resource</a></li>
<li><strong>posix.sys.socket</strong></li>
<li><a href="../modules/posix.sys.stat.html">posix.sys.stat</a></li>
<li><a href="../modules/posix.sys.statvfs.html">posix.sys.statvfs</a></li>
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<h2>Examples</h2>
<ul class="$(kind=='Topics' and '' or 'nowrap'">
<li><a href="../examples/curses.lua.html">curses.lua</a></li>
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<li><a href="../examples/fork2.lua.html">fork2.lua</a></li>
<li><a href="../examples/getopt.lua.html">getopt.lua</a></li>
<li><a href="../examples/glob.lua.html">glob.lua</a></li>
<li><a href="../examples/limit.lua.html">limit.lua</a></li>
<li><a href="../examples/lock.lua.html">lock.lua</a></li>
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<li><a href="../examples/ping.lua.html">ping.lua</a></li>
<li><a href="../examples/poll.lua.html">poll.lua</a></li>
<li><a href="../examples/rt_sched.lua.html">rt_sched.lua</a></li>
<li><a href="../examples/signal.lua.html">signal.lua</a></li>
<li><a href="../examples/socket.lua.html">socket.lua</a></li>
<li><a href="../examples/termios.lua.html">termios.lua</a></li>
<li><a href="../examples/tree.lua.html">tree.lua</a></li>
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<div id="content">
<h1>Module <code>posix.sys.socket</code></h1>
<p>BSD Sockets.</p>
<p> Where supported by the underlying system, functions and constants to create,
connect and communicate over BSD sockets. If the module loads successfully,
but there is no kernel support, then <code>posix.sys.socket.version</code> will be set,
but the unsupported APIs will be <code>nil</code>.</p>
<h2><a href="#Functions">Functions</a></h2>
<table class="function_list">
<tr>
<td class="name" nowrap><a href="#accept">accept (fd)</a></td>
<td class="summary">Accept a connection on a socket.</td>
</tr>
<tr>
<td class="name" nowrap><a href="#bind">bind (fd, addr)</a></td>
<td class="summary">Bind an address to a socket.</td>
</tr>
<tr>
<td class="name" nowrap><a href="#connect">connect (fd, addr)</a></td>
<td class="summary">Initiate a connection on a socket.</td>
</tr>
<tr>
<td class="name" nowrap><a href="#getaddrinfo">getaddrinfo (host, service[, hints])</a></td>
<td class="summary">Network address and service translation.</td>
</tr>
<tr>
<td class="name" nowrap><a href="#getsockname">getsockname (sockfd)</a></td>
<td class="summary">Get socket name.</td>
</tr>
<tr>
<td class="name" nowrap><a href="#listen">listen (fd, backlog)</a></td>
<td class="summary">Listen for connections on a socket.</td>
</tr>
<tr>
<td class="name" nowrap><a href="#recv">recv (fd, count)</a></td>
<td class="summary">Receive a message from a socket.</td>
</tr>
<tr>
<td class="name" nowrap><a href="#recvfrom">recvfrom (fd, count)</a></td>
<td class="summary">Receive a message from a socket.</td>
</tr>
<tr>
<td class="name" nowrap><a href="#send">send (fd, buffer)</a></td>
<td class="summary">Send a message from a socket.</td>
</tr>
<tr>
<td class="name" nowrap><a href="#sendto">sendto (fd, buffer, destination)</a></td>
<td class="summary">Send a message from a socket.</td>
</tr>
<tr>
<td class="name" nowrap><a href="#setsockopt">setsockopt (fd, level, name, value1[, value2])</a></td>
<td class="summary">Get and set options on sockets.</td>
</tr>
<tr>
<td class="name" nowrap><a href="#shutdown">shutdown (fd, how)</a></td>
<td class="summary">Shut down part of a full-duplex connection.</td>
</tr>
<tr>
<td class="name" nowrap><a href="#socket">socket (domain, type, options)</a></td>
<td class="summary">Create an endpoint for communication.</td>
</tr>
<tr>
<td class="name" nowrap><a href="#socketpair">socketpair (domain, socktype, options)</a></td>
<td class="summary">Create a pair of connected sockets.</td>
</tr>
</table>
<h2><a href="#Tables">Tables</a></h2>
<table class="function_list">
<tr>
<td class="name" nowrap><a href="#PosixAddrInfo">PosixAddrInfo</a></td>
<td class="summary">Address information hints.</td>
</tr>
<tr>
<td class="name" nowrap><a href="#sockaddr">sockaddr</a></td>
<td class="summary">Socket address.</td>
</tr>
</table>
<h2><a href="#Constants">Constants </a></h2>
<table class="function_list">
<tr>
<td class="name" nowrap><a href="#posix.sys.socket">posix.sys.socket</a></td>
<td class="summary">Socket constants.</td>
</tr>
</table>
<br/>
<br/>
<h2><a name="Functions"></a>Functions</h2>
<dl class="function">
<dt>
<a name = "accept"></a>
<strong>accept (fd)</strong>
</dt>
<dd>
Accept a connection on a socket.
<h3>Parameters:</h3>
<ul>
<li><span class="parameter">fd</span>
<span class="types"><span class="type">int</span></span>
socket descriptor to act on
</li>
</ul>
<h3>Returns:</h3>
<ol>
<li>
<span class="types"><span class="type">int</span></span>
connection descriptor</li>
<li>
<span class="types"><a class="type" href="http://www.lua.org/manual/5.1/manual.html#5.5">table</a></span>
connection address, if successful</li>
</ol>
<h3>Or</h3>
<ol>
<li>
nil</li>
<li>
<span class="types"><a class="type" href="http://www.lua.org/manual/5.1/manual.html#5.4">string</a></span>
error message</li>
<li>
<span class="types"><span class="type">int</span></span>
errnum</li>
</ol>
<h3>See also:</h3>
<ul>
<a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/accept.html">accept(2)</a>
</ul>
</dd>
<dt>
<a name = "bind"></a>
<strong>bind (fd, addr)</strong>
</dt>
<dd>
Bind an address to a socket.
<h3>Parameters:</h3>
<ul>
<li><span class="parameter">fd</span>
<span class="types"><span class="type">int</span></span>
socket descriptor to act on
</li>
<li><span class="parameter">addr</span>
<span class="types"><a class="type" href="../modules/posix.sys.socket.html#sockaddr">sockaddr</a></span>
socket address
</li>
</ul>
<h3>Returns:</h3>
<ol>
<span class="types"><span class="type">int</span></span>
<code>0</code>, if successful
</ol>
<h3>Or</h3>
<ol>
<li>
nil</li>
<li>
<span class="types"><a class="type" href="http://www.lua.org/manual/5.1/manual.html#5.4">string</a></span>
error message</li>
<li>
<span class="types"><span class="type">int</span></span>
errnum</li>
</ol>
<h3>See also:</h3>
<ul>
<a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/bind.html">bind(2)</a>
</ul>
</dd>
<dt>
<a name = "connect"></a>
<strong>connect (fd, addr)</strong>
</dt>
<dd>
Initiate a connection on a socket.
<h3>Parameters:</h3>
<ul>
<li><span class="parameter">fd</span>
<span class="types"><span class="type">int</span></span>
socket descriptor to act on
</li>
<li><span class="parameter">addr</span>
<span class="types"><a class="type" href="../modules/posix.sys.socket.html#sockaddr">sockaddr</a></span>
socket address
</li>
</ul>
<h3>Returns:</h3>
<ol>
<span class="types"><span class="type">int</span></span>
<code>0</code>, if successful
</ol>
<h3>Or</h3>
<ol>
<li>
nil</li>
<li>
<span class="types"><a class="type" href="http://www.lua.org/manual/5.1/manual.html#5.4">string</a></span>
error message</li>
<li>
<span class="types"><span class="type">int</span></span>
errnum</li>
</ol>
<h3>See also:</h3>
<ul>
<a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/connect.html">connect(2)</a>
</ul>
</dd>
<dt>
<a name = "getaddrinfo"></a>
<strong>getaddrinfo (host, service[, hints])</strong>
</dt>
<dd>
Network address and service translation.
<h3>Parameters:</h3>
<ul>
<li><span class="parameter">host</span>
<span class="types"><a class="type" href="http://www.lua.org/manual/5.1/manual.html#5.4">string</a></span>
name of a host
</li>
<li><span class="parameter">service</span>
<span class="types"><a class="type" href="http://www.lua.org/manual/5.1/manual.html#5.4">string</a></span>
name of service
</li>
<li><span class="parameter">hints</span>
<span class="types"><a class="type" href="../modules/posix.sys.socket.html#PosixAddrInfo">PosixAddrInfo</a></span>
table
(<em>optional</em>)
</li>
</ul>
<h3>Returns:</h3>
<ol>
<span class="types"><span class="type">list</span></span>
of <a href="../modules/posix.sys.socket.html#sockaddr">sockaddr</a> tables
</ol>
<h3>Or</h3>
<ol>
<li>
nil</li>
<li>
<span class="types"><a class="type" href="http://www.lua.org/manual/5.1/manual.html#5.4">string</a></span>
error message</li>
<li>
<span class="types"><span class="type">int</span></span>
errnum</li>
</ol>
<h3>See also:</h3>
<ul>
<a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/getaddrinfo.html">getaddrinfo(2)</a>
</ul>
<h3>Usage:</h3>
<ul>
<pre class="example">
<span class="keyword">local</span> res, errmsg, errcode = posix.getaddrinfo (<span class="string">"www.lua.org"</span>, <span class="string">"http"</span>,
{ family = P.IF_INET, socktype = P.SOCK_STREAM }
)</pre>
</ul>
</dd>
<dt>
<a name = "getsockname"></a>
<strong>getsockname (sockfd)</strong>
</dt>
<dd>
Get socket name.
<h3>Parameters:</h3>
<ul>
<li><span class="parameter">sockfd</span>
<span class="types"><span class="type">int</span></span>
socket descriptor
</li>
</ul>
<h3>Returns:</h3>
<ol>
<span class="types"><a class="type" href="../modules/posix.sys.socket.html#sockaddr">sockaddr</a></span>
the current address to which the socket <em>sockfd</em> is bound
</ol>
<h3>Or</h3>
<ol>
<li>
nil</li>
<li>
<span class="types"><a class="type" href="http://www.lua.org/manual/5.1/manual.html#5.4">string</a></span>
error message</li>
<li>
<span class="types"><span class="type">int</span></span>
errnum</li>
</ol>
<h3>See also:</h3>
<ul>
<a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/getsockname.html">getsockname(2)</a>
</ul>
<h3>Usage:</h3>
<ul>
<pre class="example">sa, err = posix.getsockname (sockfd)</pre>
</ul>
</dd>
<dt>
<a name = "listen"></a>
<strong>listen (fd, backlog)</strong>
</dt>
<dd>
Listen for connections on a socket.
<h3>Parameters:</h3>
<ul>
<li><span class="parameter">fd</span>
<span class="types"><span class="type">int</span></span>
socket descriptor to act on
</li>
<li><span class="parameter">backlog</span>
<span class="types"><span class="type">int</span></span>
maximum length for queue of pending connections
</li>
</ul>
<h3>Returns:</h3>
<ol>
<span class="types"><span class="type">int</span></span>
<code>0</code>, if successful
</ol>
<h3>Or</h3>
<ol>
<li>
nil</li>
<li>
<span class="types"><a class="type" href="http://www.lua.org/manual/5.1/manual.html#5.4">string</a></span>
error message</li>
<li>
<span class="types"><span class="type">int</span></span>
errnum</li>
</ol>
<h3>See also:</h3>
<ul>
<a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/listen.html">listen(2)</a>
</ul>
</dd>
<dt>
<a name = "recv"></a>
<strong>recv (fd, count)</strong>
</dt>
<dd>
Receive a message from a socket.
<h3>Parameters:</h3>
<ul>
<li><span class="parameter">fd</span>
<span class="types"><span class="type">int</span></span>
socket descriptor to act on
</li>
<li><span class="parameter">count</span>
<span class="types"><span class="type">int</span></span>
maximum number of bytes to receive
</li>
</ul>
<h3>Returns:</h3>
<ol>
<span class="types"><span class="type">int</span></span>
received bytes, if successful
</ol>
<h3>Or</h3>
<ol>
<li>
nil</li>
<li>
<span class="types"><a class="type" href="http://www.lua.org/manual/5.1/manual.html#5.4">string</a></span>
error message</li>
<li>
<span class="types"><span class="type">int</span></span>
errnum</li>
</ol>
<h3>See also:</h3>
<ul>
<a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/recv.html">recv(2)</a>
</ul>
</dd>
<dt>
<a name = "recvfrom"></a>
<strong>recvfrom (fd, count)</strong>
</dt>
<dd>
Receive a message from a socket.
<h3>Parameters:</h3>
<ul>
<li><span class="parameter">fd</span>
<span class="types"><span class="type">int</span></span>
socket descriptor to act on
</li>
<li><span class="parameter">count</span>
<span class="types"><span class="type">int</span></span>
maximum number of bytes to receive
</li>
</ul>
<h3>Returns:</h3>
<ol>
<li>
<span class="types"><span class="type">int</span></span>
received bytes</li>
<li>
<span class="types"><a class="type" href="../modules/posix.sys.socket.html#sockaddr">sockaddr</a></span>
address of message source, if successful</li>
</ol>
<h3>Or</h3>
<ol>
<li>
nil</li>
<li>
<span class="types"><a class="type" href="http://www.lua.org/manual/5.1/manual.html#5.4">string</a></span>
error message</li>
<li>
<span class="types"><span class="type">int</span></span>
errnum</li>
</ol>
<h3>See also:</h3>
<ul>
<a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/recvfrom.html">recvfrom(2)</a>
</ul>
</dd>
<dt>
<a name = "send"></a>
<strong>send (fd, buffer)</strong>
</dt>
<dd>
Send a message from a socket.
<h3>Parameters:</h3>
<ul>
<li><span class="parameter">fd</span>
<span class="types"><span class="type">int</span></span>
socket descriptor to act on
</li>
<li><span class="parameter">buffer</span>
<span class="types"><a class="type" href="http://www.lua.org/manual/5.1/manual.html#5.4">string</a></span>
message bytes to send
</li>
</ul>
<h3>Returns:</h3>
<ol>
<span class="types"><span class="type">int</span></span>
number of bytes sent, if successful
</ol>
<h3>Or</h3>
<ol>
<li>
nil</li>
<li>
<span class="types"><a class="type" href="http://www.lua.org/manual/5.1/manual.html#5.4">string</a></span>
error message</li>
<li>
<span class="types"><span class="type">int</span></span>
errnum</li>
</ol>
<h3>See also:</h3>
<ul>
<a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/send.html">send(2)</a>
</ul>
</dd>
<dt>
<a name = "sendto"></a>
<strong>sendto (fd, buffer, destination)</strong>
</dt>
<dd>
Send a message from a socket.
<h3>Parameters:</h3>
<ul>
<li><span class="parameter">fd</span>
<span class="types"><span class="type">int</span></span>
socket descriptor to act on
</li>
<li><span class="parameter">buffer</span>
<span class="types"><a class="type" href="http://www.lua.org/manual/5.1/manual.html#5.4">string</a></span>
message bytes to send
</li>
<li><span class="parameter">destination</span>
<span class="types"><a class="type" href="../modules/posix.sys.socket.html#sockaddr">sockaddr</a></span>
socket address
</li>
</ul>
<h3>Returns:</h3>
<ol>
<span class="types"><span class="type">int</span></span>
number of bytes sent, if successful
</ol>
<h3>Or</h3>
<ol>
<li>
nil</li>
<li>
<span class="types"><a class="type" href="http://www.lua.org/manual/5.1/manual.html#5.4">string</a></span>
error message</li>
<li>
<span class="types"><span class="type">int</span></span>
errnum</li>
</ol>
<h3>See also:</h3>
<ul>
<a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/sendto.html">sendto(2)</a>
</ul>
</dd>
<dt>
<a name = "setsockopt"></a>
<strong>setsockopt (fd, level, name, value1[, value2])</strong>
</dt>
<dd>
Get and set options on sockets.
<h3>Parameters:</h3>
<ul>
<li><span class="parameter">fd</span>
<span class="types"><span class="type">int</span></span>
socket descriptor
</li>
<li><span class="parameter">level</span>
<span class="types"><span class="type">int</span></span>
one of <code>SOL_SOCKET</code>, <code>IPPROTO_IPV6</code>, <code>IPPROTO_TCP</code>
</li>
<li><span class="parameter">name</span>
<span class="types"><span class="type">int</span></span>
option name, varies according to <code>level</code> value
</li>
<li><span class="parameter">value1</span>
option value to set
</li>
<li><span class="parameter">value2</span>
some option <em>name</em>s need an additional value
(<em>optional</em>)
</li>
</ul>
<h3>Returns:</h3>
<ol>
<span class="types"><span class="type">int</span></span>
<code>0</code>, if successful
</ol>
<h3>Or</h3>
<ol>
<li>
nil</li>
<li>
<span class="types"><a class="type" href="http://www.lua.org/manual/5.1/manual.html#5.4">string</a></span>
error message</li>
<li>
<span class="types"><span class="type">int</span></span>
errnum</li>
</ol>
<h3>See also:</h3>
<ul>
<a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/setsockopt.html">setsockopt(2)</a>
</ul>
<h3>Usage:</h3>
<ul>
<pre class="example">ok, errmsg = P.setsockopt (sock, P.SOL_SOCKET, P.SO_SNDTIMEO, <span class="number">1</span>, <span class="number">0</span>)</pre>
</ul>
</dd>
<dt>
<a name = "shutdown"></a>
<strong>shutdown (fd, how)</strong>
</dt>
<dd>
Shut down part of a full-duplex connection.
<h3>Parameters:</h3>
<ul>
<li><span class="parameter">fd</span>
<span class="types"><span class="type">int</span></span>
socket descriptor to act on
</li>
<li><span class="parameter">how</span>
<span class="types"><span class="type">int</span></span>
one of <code>SHUT_RD</code>, <code>SHUT_WR</code> or <code>SHUT_RDWR</code>
</li>
</ul>
<h3>Returns:</h3>
<ol>
<span class="types"><span class="type">int</span></span>
<code>0</code>, if successful
</ol>
<h3>Or</h3>
<ol>
<li>
nil</li>
<li>
<span class="types"><a class="type" href="http://www.lua.org/manual/5.1/manual.html#5.4">string</a></span>
error message</li>
<li>
<span class="types"><span class="type">int</span></span>
errnum</li>
</ol>
<h3>See also:</h3>
<ul>
<a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/shutdown.html">shutdown(2)</a>
</ul>
<h3>Usage:</h3>
<ul>
<pre class="example">ok, errmsg = P.shutdown (sock, P.SHUT_RDWR)</pre>
</ul>
</dd>
<dt>
<a name = "socket"></a>
<strong>socket (domain, type, options)</strong>
</dt>
<dd>
Create an endpoint for communication.
<h3>Parameters:</h3>
<ul>
<li><span class="parameter">domain</span>
<span class="types"><span class="type">int</span></span>
one of <code>AF_INET</code>, <code>AF_INET6</code>, <code>AF_UNIX</code> or <code>AF_NETLINK</code>
</li>
<li><span class="parameter">type</span>
<span class="types"><span class="type">int</span></span>
one of <code>SOCK_STREAM</code>, <code>SOCK_DGRAM</code> or <code>SOCK_RAW</code>
</li>
<li><span class="parameter">options</span>
<span class="types"><span class="type">int</span></span>
usually 0, but some socket types might implement other protocols.
</li>
</ul>
<h3>Returns:</h3>
<ol>
<span class="types"><span class="type">int</span></span>
socket descriptor, if successful
</ol>
<h3>Or</h3>
<ol>
<li>
nil</li>
<li>
<span class="types"><a class="type" href="http://www.lua.org/manual/5.1/manual.html#5.4">string</a></span>
error message</li>
<li>
<span class="types"><span class="type">int</span></span>
errnum</li>
</ol>
<h3>See also:</h3>
<ul>
<a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/socket.html">socket(2)</a>
</ul>
<h3>Usage:</h3>
<ul>
<pre class="example">sockd = P.socket (P.AF_INET, P.SOCK_STREAM, <span class="number">0</span>)</pre>
</ul>
</dd>
<dt>
<a name = "socketpair"></a>
<strong>socketpair (domain, socktype, options)</strong>
</dt>
<dd>
Create a pair of connected sockets.
<h3>Parameters:</h3>
<ul>
<li><span class="parameter">domain</span>
<span class="types"><span class="type">int</span></span>
one of <code>AF_INET</code>, <code>AF_INET6</code>, <code>AF_UNIX</code> or <code>AF_NETLINK</code>
</li>
<li><span class="parameter">socktype</span>
<span class="types"><span class="type">int</span></span>
one of <code>SOCK_STREAM</code>, <code>SOCK_DGRAM</code> or <code>SOCK_RAW</code>
</li>
<li><span class="parameter">options</span>
<span class="types"><span class="type">int</span></span>
usually 0, but some socket types might implement other protocols.
</li>
</ul>
<h3>Returns:</h3>
<ol>
<li>
<span class="types"><span class="type">int</span></span>
descriptor of one end of the socket pair</li>
<li>
<span class="types"><span class="type">int</span></span>
descriptor of the other end of the pair, if successful</li>
</ol>
<h3>Or</h3>
<ol>
<li>
nil</li>
<li>
<span class="types"><a class="type" href="http://www.lua.org/manual/5.1/manual.html#5.4">string</a></span>
error message</li>
<li>
<span class="types"><span class="type">int</span></span>
errnum</li>
</ol>
<h3>Usage:</h3>
<ul>
<pre class="example">sockr, sockw = P.socketpair (P.AF_INET, P.SOCK_STREAM, <span class="number">0</span>)</pre>
</ul>
</dd>
</dl>
<h2><a name="Tables"></a>Tables</h2>
<dl class="function">
<dt>
<a name = "PosixAddrInfo"></a>
<strong>PosixAddrInfo</strong>
</dt>
<dd>
Address information hints.
<h3>Fields:</h3>
<ul>
<li><span class="parameter">family</span>
<span class="types"><span class="type">int</span></span>
one of <code>AF_INET</code>, <code>AF_INET6</code>, <code>AF_UNIX</code> or <code>AF_NETLINK</code>
</li>
<li><span class="parameter">flags</span>
<span class="types"><span class="type">int</span></span>
bitwise OR of zero or more of <code>AI_ADDRCONFIG</code>, <code>AI_ALL</code>,
<code>AI_CANONNAME</code>, <code>AI_NUMERICHOST</code>, <code>AI_NUMERICSERV</code>, <code>AI_PASSIVE</code> and
<code>AI_V4MAPPED</code>
</li>
<li><span class="parameter">socktype</span>
<span class="types"><span class="type">int</span></span>
one of <code>SOCK_STREAM</code>, <code>SOCK_DGRAM</code> or <code>SOCK_RAW</code>
</li>
<li><span class="parameter">protocol</span>
<span class="types"><span class="type">int</span></span>
one of <code>IPPROTO_TCP</code> or <code>IPPROTO_UDP</code>
</li>
</ul>
</dd>
<dt>
<a name = "sockaddr"></a>
<strong>sockaddr</strong>
</dt>
<dd>
Socket address.
All sockaddr tables have the <em>family</em> field, and depending on its value, also
a subset of the following fields too.
<h3>Fields:</h3>
<ul>
<li><span class="parameter">family</span>
<span class="types"><span class="type">int</span></span>
one of <code>AF_INET</code>, <code>AF_INET6</code>, <code>AF_UNIX</code> or (where supported) <code>AF_NETLINK</code>
</li>
<li><span class="parameter">port</span>
<span class="types"><span class="type">int</span></span>
socket port number for <code>AF_INET</code> (and equivalently <code>AF_INET6</code>) <em>family</em>
(<em>optional</em>)
</li>
<li><span class="parameter">addr</span>
<span class="types"><a class="type" href="http://www.lua.org/manual/5.1/manual.html#5.4">string</a></span>
socket host address in correct format, for <code>AF_INET</code> <em>family</em>
(<em>optional</em>)
</li>
<li><span class="parameter">socktype</span>
<span class="types"><span class="type">int</span></span>
one of <code>SOCK_STREAM</code>, <code>SOCK_DGRAM</code> or <code>SOCK_RAW</code> for <code>AF_INET</code> <em>family</em>
(<em>optional</em>)
</li>
<li><span class="parameter">canonname</span>
<span class="types"><a class="type" href="http://www.lua.org/manual/5.1/manual.html#5.4">string</a></span>
canonical name for service location, for <code>AF_INET</code> <em>family</em>
(<em>optional</em>)
</li>
<li><span class="parameter">protocol</span>
<span class="types"><span class="type">int</span></span>
one of <code>IPPROTO_TCP</code> or <code>IPPROTO_UDP</code>, for <code>AF_INET</code> <em>family</em>
(<em>optional</em>)
</li>
<li><span class="parameter">path</span>
<span class="types"><a class="type" href="http://www.lua.org/manual/5.1/manual.html#5.4">string</a></span>
location in file system, for <code>AF_UNIX</code> <em>family</em>
(<em>optional</em>)
</li>
<li><span class="parameter">pid</span>
<span class="types"><span class="type">int</span></span>
process identifier, for <code>AF_NETLINK</code> <em>family</em>
(<em>optional</em>)
</li>
<li><span class="parameter">groups</span>
<span class="types"><span class="type">int</span></span>
process group owner identifier, for <code>AF_NETLINK</code> <em>family</em>
(<em>optional</em>)
</li>
</ul>
</dd>
</dl>
<h2><a name="Constants"></a>Constants </h2>
<dl class="function">
<dt>
<a name = "posix.sys.socket"></a>
<strong>posix.sys.socket</strong>
</dt>
<dd>
Socket constants.
Any constants not available in the underlying system will be <code>nil</code> valued.
<h3>Fields:</h3>
<ul>
<li><span class="parameter">AF_INET</span>
<span class="types"><span class="type">int</span></span>
IP protocol family
</li>
<li><span class="parameter">AF_INET6</span>
<span class="types"><span class="type">int</span></span>
IP version 6
</li>
<li><span class="parameter">AF_NETLINK</span>
<span class="types"><span class="type">int</span></span>
Netlink protocol family
</li>
<li><span class="parameter">AF_UNIX</span>
<span class="types"><span class="type">int</span></span>
local to host
</li>
<li><span class="parameter">AF_UNSPEC</span>
<span class="types"><span class="type">int</span></span>
unspecified
</li>
<li><span class="parameter">AI_ADDRCONFIG</span>
<span class="types"><span class="type">int</span></span>
use host configuration for returned address type
</li>
<li><span class="parameter">AI_ALL</span>
<span class="types"><span class="type">int</span></span>
return IPv4 mapped and IPv6 addresses
</li>
<li><span class="parameter">AI_CANONNAME</span>
<span class="types"><span class="type">int</span></span>
request canonical name
</li>
<li><span class="parameter">AI_NUMERICHOST</span>
<span class="types"><span class="type">int</span></span>
don't use domain name resolution
</li>
<li><span class="parameter">AI_NUMERICSERV</span>
<span class="types"><span class="type">int</span></span>
don't use service name resolution
</li>
<li><span class="parameter">AI_PASSIVE</span>
<span class="types"><span class="type">int</span></span>
address is intended for <a href="../modules/posix.sys.socket.html#bind">bind</a>
</li>
<li><span class="parameter">AI_V4MAPPED</span>
<span class="types"><span class="type">int</span></span>
IPv4 mapped addresses are acceptable
</li>
<li><span class="parameter">IPPROTO_ICMP</span>
<span class="types"><span class="type">int</span></span>
internet control message protocol
</li>
<li><span class="parameter">IPPROTO_IP</span>
<span class="types"><span class="type">int</span></span>
internet protocol
</li>
<li><span class="parameter">IPPROTO_IPV6</span>
<span class="types"><span class="type">int</span></span>
IPv6 header
</li>
<li><span class="parameter">IPPROTO_TCP</span>
<span class="types"><span class="type">int</span></span>
transmission control protocol
</li>
<li><span class="parameter">IPPROTO_UDP</span>
<span class="types"><span class="type">int</span></span>
user datagram protocol
</li>
<li><span class="parameter">IPV6_JOIN_GROUP</span>
<span class="types"><span class="type">int</span></span>
</li>
<li><span class="parameter">IPV6_LEAVE_GROUP</span>
<span class="types"><span class="type">int</span></span>
</li>
<li><span class="parameter">IPV6_MULTICAST_HOPS</span>
<span class="types"><span class="type">int</span></span>
</li>
<li><span class="parameter">IPV6_MULTICAST_IF</span>
<span class="types"><span class="type">int</span></span>
</li>
<li><span class="parameter">IPV6_MULTICAST_LOOP</span>
<span class="types"><span class="type">int</span></span>
</li>
<li><span class="parameter">IPV6_UNICAST_HOPS</span>
<span class="types"><span class="type">int</span></span>
</li>
<li><span class="parameter">IPV6_V6ONLY</span>
<span class="types"><span class="type">int</span></span>
</li>
<li><span class="parameter">NETLINK_AUDIT</span>
<span class="types"><span class="type">int</span></span>
auditing
</li>
<li><span class="parameter">NETLINK_CONNECTOR</span>
<span class="types"><span class="type">int</span></span>
</li>
<li><span class="parameter">NETLINK_DNRTMSG</span>
<span class="types"><span class="type">int</span></span>
decnet routing messages
</li>
<li><span class="parameter">NETLINK_ECRYPTFS</span>
<span class="types"><span class="type">int</span></span>
</li>
<li><span class="parameter">NETLINK_FIB_LOOKUP</span>
<span class="types"><span class="type">int</span></span>
</li>
<li><span class="parameter">NETLINK_FIREWALL</span>
<span class="types"><span class="type">int</span></span>
firewalling hook
</li>
<li><span class="parameter">NETLINK_GENERIC</span>
<span class="types"><span class="type">int</span></span>
</li>
<li><span class="parameter">NETLINK_IP6_FW</span>
<span class="types"><span class="type">int</span></span>
</li>
<li><span class="parameter">NETLINK_ISCSI</span>
<span class="types"><span class="type">int</span></span>
open iSCSI
</li>
<li><span class="parameter">NETLINK_KOBJECT_UEVENT</span>
<span class="types"><span class="type">int</span></span>
kernel messages to userspace
</li>
<li><span class="parameter">NETLINK_NETFILTER</span>
<span class="types"><span class="type">int</span></span>
netfilter subsystem
</li>
<li><span class="parameter">NETLINK_NFLOG</span>
<span class="types"><span class="type">int</span></span>
netfilter/iptables ULOG
</li>
<li><span class="parameter">NETLINK_ROUTE</span>
<span class="types"><span class="type">int</span></span>
routing/device hook
</li>
<li><span class="parameter">NETLINK_SCSITRANSPORT</span>
<span class="types"><span class="type">int</span></span>
SCSI transports
</li>
<li><span class="parameter">NETLINK_SELINUX</span>
<span class="types"><span class="type">int</span></span>
SELinux event notifications
</li>
<li><span class="parameter">NETLINK_UNUSED</span>
<span class="types"><span class="type">int</span></span>
unused number
</li>
<li><span class="parameter">NETLINK_USERSOCK</span>
<span class="types"><span class="type">int</span></span>
reserved for user mode socket protocols
</li>
<li><span class="parameter">NETLINK_XFRM</span>
<span class="types"><span class="type">int</span></span>
ipsec
</li>
<li><span class="parameter">SHUT_RD</span>
<span class="types"><span class="type">int</span></span>
no more receptions
</li>
<li><span class="parameter">SHUT_RDWR</span>
<span class="types"><span class="type">int</span></span>
no more receptions or transmissions
</li>
<li><span class="parameter">SHUT_WR</span>
<span class="types"><span class="type">int</span></span>
no more transmissions
</li>
<li><span class="parameter">SOCK_DGRAM</span>
<span class="types"><span class="type">int</span></span>
connectionless unreliable datagrams
</li>
<li><span class="parameter">SOCK_RAW</span>
<span class="types"><span class="type">int</span></span>
raw protocol interface
</li>
<li><span class="parameter">SOCK_STREAM</span>
<span class="types"><span class="type">int</span></span>
connection based byte stream
</li>
<li><span class="parameter">SOL_SOCKET</span>
<span class="types"><span class="type">int</span></span>
socket level
</li>
<li><span class="parameter">SOMAXCONN</span>
<span class="types"><span class="type">int</span></span>
maximum concurrent connections
</li>
<li><span class="parameter">SO_ACCEPTCONN</span>
<span class="types"><span class="type">int</span></span>
does this socket accept connections
</li>
<li><span class="parameter">SO_BINDTODEVICE</span>
<span class="types"><span class="type">int</span></span>
bind to a particular device
</li>
<li><span class="parameter">SO_BROADCAST</span>
<span class="types"><span class="type">int</span></span>
permit broadcasts
</li>
<li><span class="parameter">SO_DEBUG</span>
<span class="types"><span class="type">int</span></span>
turn-on socket debugging
</li>
<li><span class="parameter">SO_DONTROUTE</span>
<span class="types"><span class="type">int</span></span>
bypass standard routing
</li>
<li><span class="parameter">SO_ERROR</span>
<span class="types"><span class="type">int</span></span>
set socket error flag
</li>
<li><span class="parameter">SO_KEEPALIVE</span>
<span class="types"><span class="type">int</span></span>
periodically transmit keep-alive message
</li>
<li><span class="parameter">SO_LINGER</span>
<span class="types"><span class="type">int</span></span>
linger on a <a href="../modules/posix.unistd.html#close">posix.unistd.close</a> if data is still present
</li>
<li><span class="parameter">SO_OOBINLINE</span>
<span class="types"><span class="type">int</span></span>
leave out-of-band data inline
</li>
<li><span class="parameter">SO_RCVBUF</span>
<span class="types"><span class="type">int</span></span>
set receive buffer size
</li>
<li><span class="parameter">SO_RCVLOWAT</span>
<span class="types"><span class="type">int</span></span>
set receive buffer low water mark
</li>
<li><span class="parameter">SO_RCVTIMEO</span>
<span class="types"><span class="type">int</span></span>
set receive timeout
</li>
<li><span class="parameter">SO_REUSEADDR</span>
<span class="types"><span class="type">int</span></span>
reuse local addresses
</li>
<li><span class="parameter">SO_SNDBUF</span>
<span class="types"><span class="type">int</span></span>
set send buffer size
</li>
<li><span class="parameter">SO_SNDLOWAT</span>
<span class="types"><span class="type">int</span></span>
set send buffer low water mark
</li>
<li><span class="parameter">SO_SNDTIMEO</span>
<span class="types"><span class="type">int</span></span>
set send timeout
</li>
<li><span class="parameter">SO_TYPE</span>
<span class="types"><span class="type">int</span></span>
get the socket type
</li>
<li><span class="parameter">TCP_NODELAY</span>
<span class="types"><span class="type">int</span></span>
don't delay send for packet coalescing
</li>
</ul>
<h3>Usage:</h3>
<ul>
<pre class="example">
<span class="comment">-- Print socket constants supported on this host.
</span> <span class="keyword">for</span> name, value <span class="keyword">in</span> <span class="global">pairs</span> (<span class="global">require</span> <span class="string">"posix.sys.socket"</span>) <span class="keyword">do</span>
<span class="keyword">if</span> <span class="global">type</span> (value) == <span class="string">"number"</span> <span class="keyword">then</span>
<span class="global">print</span> (name, value)
<span class="keyword">end</span>
<span class="keyword">end</span></pre>
</ul>
</dd>
</dl>
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