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<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE erlref SYSTEM "erlref.dtd">

<erlref>
  <header>
    <copyright>
      <year>2018</year><year>2018</year>
      <holder>Ericsson AB. All Rights Reserved.</holder>
    </copyright>
    <legalnotice>
      Licensed under the Apache License, Version 2.0 (the "License");
      you may not use this file except in compliance with the License.
      You may obtain a copy of the License at
 
          http://www.apache.org/licenses/LICENSE-2.0

      Unless required by applicable law or agreed to in writing, software
      distributed under the License is distributed on an "AS IS" BASIS,
      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      See the License for the specific language governing permissions and
      limitations under the License.

    </legalnotice>

    <title>socket</title>
    <prepared></prepared>
    <docno></docno>
    <date></date>
    <rev></rev>
    <file>socket.xml</file>
  </header>
  <module>socket</module>
  <modulesummary>Socket interface.</modulesummary>
  <description>
    <p>This module provides an API for the socket interface.
      It is used to create, delete and manipulate sockets.</p>
  </description>

  <datatypes>
    <datatype>
      <name name="domain"/>
    </datatype>
    <datatype>
      <name name="type"/>
    </datatype>
    <datatype>
      <name name="protocol"/>
    </datatype>
    <datatype>
      <name>socket()</name>
      <desc><p>As returned by
        <seealso marker="#open/1"><c>open/2,3,4</c></seealso> and
        <seealso marker="#accept/1"><c>accept/1,2</c></seealso>.</p>
      </desc>
    </datatype>
    <datatype>
      <name name="ip4_address"/>
    </datatype>
    <datatype>
      <name name="ip6_address"/>
    </datatype>
    <datatype>
      <name name="ip_address"/>
    </datatype>
    <datatype>
      <name name="in4_sockaddr"/>
    </datatype>
    <datatype>
      <name name="in6_sockaddr"/>
    </datatype>
    <datatype>
      <name name="in_sockaddr"/>
    </datatype>
    <datatype>
      <name name="port_number"/>
    </datatype>
    <datatype>
      <name name="accept_flags"/>
    </datatype>
    <datatype>
      <name name="accept_flag"/>
    </datatype>
    <datatype>
      <name name="send_flags"/>
    </datatype>
    <datatype>
      <name name="send_flag"/>
    </datatype>
    <datatype>
      <name name="shutdown_how"/>
    </datatype>
    <datatype>
      <name name="sockopt_level"/>
    </datatype>
    <datatype>
      <name name="otp_socket_option"/>
    </datatype>
    <datatype>
      <name name="socket_option"/>
    </datatype>
    <datatype>
      <name name="ip_socket_option"/>
    </datatype>
    <datatype>
      <name name="ipv6_socket_option"/>
    </datatype>
    <datatype>
      <name name="tcp_socket_option"/>
    </datatype>
    <datatype>
      <name name="udp_socket_option"/>
    </datatype>
    <datatype>
      <name name="sctp_socket_option"/>
    </datatype>
    <datatype>
      <name name="ip_tos_flag"/>
    </datatype>
  </datatypes>

  <funcs>
    <func>
      <name name="accept" arity="1"/>
      <name name="accept" arity="2"/>
      <fsummary>Accept a connection on a socket.</fsummary>
      <desc>
        <p>Accept a connection on a socket.</p>
        <p>This call is used with connection-based socket types
	(stream or seqpacket). It extracs the first pending connection
	request for the listen socket and returns the (newly) connected
	socket.</p>
      </desc>
    </func>

    <func>
      <name name="bind" arity="2"/>
      <fsummary>Bind a name to a socket.</fsummary>
      <desc>
        <p>Bind a name to a socket.</p>
        <p>When a socket is created
	(with <seealso marker="#open/2"><c>open</c></seealso>),
	it has no address assigned to it. <c>bind</c> assigns the
	address specified by the <c>Addr</c> argument.</p>
	<p>The rules used for name binding vary between domains.</p>
      </desc>
    </func>

    <func>
      <name name="close" arity="1"/>
      <fsummary>Close a socket.</fsummary>
      <desc>
        <p>Closes the socket.</p>
      </desc>
    </func>

    <func>
      <name name="connect" arity="2"/>
      <name name="connect" arity="3"/>
      <fsummary>Initiate a connection on a socket.</fsummary>
      <desc>
        <p>This function connects the socket to the address
	specied by the <c>Addr</c> argument.</p>
      </desc>
    </func>

    <func>
      <name name="getopt" arity="3" clause_i="1"/>
      <name name="getopt" arity="3" clause_i="2"/>
      <name name="getopt" arity="3" clause_i="3"/>
      <name name="getopt" arity="3" clause_i="4"/>
      <name name="getopt" arity="3" clause_i="5"/>
      <name name="getopt" arity="3" clause_i="6"/>
      <name name="getopt" arity="3" clause_i="7"/>
      <name name="getopt" arity="3" clause_i="8"/>
      <fsummary>Get an option on a socket.</fsummary>
      <desc>
        <p>Get an option on a socket.</p>
        <p>What properties are valid depend on what kind of socket
	it is (<c>domain</c>, <c>type</c> and <c>protocol</c>).</p>
	<p>When specifying <c>Level</c> as an integer, and therefor
	using "native mode", it is *currently* up to the caller to
	know how to interpret the result.</p>

	<note><p>Not all options are valid on all platforms. That is,
	even if "we" support an option, that does not mean that the
	underlying OS does.</p></note>
      </desc>
    </func>

    <func>
      <name name="listen" arity="1"/>
      <name name="listen" arity="2"/>
      <fsummary>Listen for connections on a socket.</fsummary>
      <desc>
        <p>Listen for connections on a socket.</p>
      </desc>
    </func>

    <func>
      <name name="open" arity="2"/>
      <name name="open" arity="3"/>
      <name name="open" arity="4"/>
      <fsummary>Create an endpoint for communication.</fsummary>
      <desc>
        <p>Creates an endpoint (socket) for communication.</p>
        <p>For some <c>types</c> there is a default protocol, which will
	be used if no protocol is specified: </p>

	<list>
	  <item><p><c>stream</c>: <c>tcp</c></p></item>
          <item><p><c>dgram</c>: <c>udp</c></p></item>
          <item><p><c>seqpacket</c>: <c>sctp</c></p></item>
	</list>

	<p>The <c>Extra</c> argument is intended for "obscure" options.
	Currently the only supported option is <c>netns</c>, which
	is only supported on the linux platform.</p>
      </desc>
    </func>

    <func>
      <name name="recv" arity="2"/>
      <name name="recv" arity="3"/>
      <name name="recv" arity="4"/>
      <fsummary>Receive a message from a socket.</fsummary>
      <desc>
        <p>Receive a message from a socket.</p>
	<p>There is a special case for the argument <c>Length</c>.
	If it is set to zero (0), it means "give me everything you 
	currently have".</p>
      </desc>
    </func>

    <func>
      <name name="recvfrom" arity="1"/>
      <name name="recvfrom" arity="2"/>
      <name name="recvfrom" arity="3"/>
      <name name="recvfrom" arity="4"/>
      <fsummary>Receive a message from a socket.</fsummary>
      <desc>
        <p>Receive a message from a socket.</p>
        <p>This function reads "messages", which means that regardless of
	how much we want to read, it returns when we get a message.</p>
        <p>The <c>MaxSize</c> argument basically defines the size of the
	receive buffer. By setting the value to zero (0), the configured
	size (setopt) is used.</p>
        <p>It may be impossible to know what (buffer) size is appropriate
	"in advance", and in those cases it may be convenient to use the
	(recv) 'peek' flag. When this flag is provided the message is *not*
	"consumed" from the underlying buffers, so another recvfrom call
	is needed, possibly with a then adjusted buffer size.</p>
      </desc>
    </func>

    <func>
      <name name="send" arity="2"/>
      <name name="send" arity="3"/>
      <name name="send" arity="4"/>
      <fsummary>Send a message on a socket.</fsummary>
      <desc>
        <p>Send a message on a connected socket.</p>
      </desc>
    </func>

    <func>
      <name name="sendto" arity="4"/>
      <name name="sendto" arity="5"/>
      <fsummary>Send a message on a socket.</fsummary>
      <desc>
        <p>Send a message on a socket, to the specified destination.</p>
      </desc>
    </func>

    <func>
      <name name="setopt" arity="4" clause_i="1"/>
      <name name="setopt" arity="4" clause_i="2"/>
      <name name="setopt" arity="4" clause_i="3"/>
      <name name="setopt" arity="4" clause_i="4"/>
      <name name="setopt" arity="4" clause_i="5"/>
      <name name="setopt" arity="4" clause_i="6"/>
      <name name="setopt" arity="4" clause_i="7"/>
      <fsummary>Set options on a socket.</fsummary>
      <desc>
        <p>Set options on a socket.</p>
	<p>What properties are valid depend both on <c>Level</c> and on
	what kind of socket it is (<c>domain</c>, <c>type</c> and
	<c>protocol</c>).</p>

	<note><p>Not all options are valid on all platforms. That is,
	even if "we" support an option, that does not mean that the
	underlying OS does.</p></note>

	<note><p>Sockets are set 'non-blocking' when created, so this option
	is *not* available (as it would adversely effect the Erlang VM
	to set a socket 'blocking').</p></note>
      </desc>
    </func>

    <func>
      <name name="shutdown" arity="2"/>
      <fsummary>Shut down part of a full-duplex connection.</fsummary>
      <desc>
        <p>Shut down all or part of a full-duplex connection.</p>
      </desc>
    </func>

  </funcs>
</erlref>