PHP Socket Basic

<?
// set some variables
$host = "192.168.1.99";
$port = 1234;
// don't timeout!
set_time_limit(0);
// create socket
$socket = socket_create(AF_INET, SOCK_STREAM, 0) or die("Could not create
socket\n");
// bind socket to port
$result = socket_bind($socket, $host, $port) or die("Could not bind to
socket\n");
// start listening for connections
$result = socket_listen($socket, 3) or die("Could not set up socket
listener\n");
// accept incoming connections
// spawn another socket to handle communication
$spawn = socket_accept($socket) or die("Could not accept incoming
connection\n");
// read client input
$input = socket_read($spawn, 1024) or die("Could not read input\n");
// clean up input string
$input = trim($input);
// reverse client input and send back
$output = strrev($input) . "\n";
socket_write($spawn, $output, strlen ($output)) or die("Could not write
output\n");
// close sockets
socket_close($spawn);
socket_close($socket);
?>