php man page for stream_socket_pair

STREAM_SOCKET_PAIR(3)							 1						     STREAM_SOCKET_PAIR(3)

stream_socket_pair - Creates a pair of connected, indistinguishable socket streams

SYNOPSIS
       array stream_socket_pair (int  $domain, int  $type, int	$protocol)

DESCRIPTION
       stream_socket_pair(3)  creates  a pair of connected, indistinguishable socket streams. This function is commonly used in IPC (Inter-Process
       Communication).

PARAMETERS
	      o $domain
		- The protocol family to be used: STREAM_PF_INET, STREAM_PF_INET6 or STREAM_PF_UNIX

	      o $type
		-  The	type  of  communication  to  be  used:	STREAM_SOCK_DGRAM,  STREAM_SOCK_RAW,  STREAM_SOCK_RDM,	STREAM_SOCK_SEQPACKET	or
		STREAM_SOCK_STREAM

	      o $protocol
		- The protocol to be used: STREAM_IPPROTO_ICMP, STREAM_IPPROTO_IP, STREAM_IPPROTO_RAW, STREAM_IPPROTO_TCP or STREAM_IPPROTO_UDP

       Note

	       Please consult the Streams constant list for further details on each constant.

RETURN VALUES
	Returns an array with the two socket resources on success, or FALSE on failure.

CHANGELOG
       +--------+---------------------------------------------------+
       |Version |						    |
       |	|						    |
       |	|		     Description		    |
       |	|						    |
       +--------+---------------------------------------------------+
       | 5.3.0	|						    |
       |	|						    |
       |	|  This  function is now available on Windows plat- |
       |	| forms.					    |
       |	|						    |
       +--------+---------------------------------------------------+
EXAMPLES
       Example #1

	      A stream_socket_pair(3) example

	       This example shows the basic usage of stream_socket_pair(3) in Inter-Process Comunication.

	      <?php

	      $sockets = stream_socket_pair(STREAM_PF_UNIX, STREAM_SOCK_STREAM, STREAM_IPPROTO_IP);
	      $pid     = pcntl_fork();

	      if ($pid == -1) {
		   die('could not fork');

	      } else if ($pid) {
		   /* parent */
		  fclose($sockets[0]);

		  fwrite($sockets[1], "child PID: $pid
");
		  echo fgets($sockets[1]);

		  fclose($sockets[1]);

	      } else {
		  /* child */
		  fclose($sockets[1]);

		  fwrite($sockets[0], "message from child
");
		  echo fgets($sockets[0]);

		  fclose($sockets[0]);
	      }

	      ?>

	      The above example will output something similar to:

	      child PID: 1378
	      message from child

PHP Documentation Group 												     STREAM_SOCKET_PAIR(3)