socket和pack的有关问题

$message = '';<br />$message .= pack("a99", $mail);<br />$message .= pack("a32", $pass);<br />$message .= pack("a19", $action);<br />$from = '';<br />$port = 0;<br />//echo $message;<br /><br />if ($socket = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP))<br />{<br />	//socket_bind($socket, '127.0.0.1', 27015);<br />	socket_sendto($socket, $message, strlen($message), 0, $server_ip, $server_port);<br />	$ret = socket_recvfrom($socket, $result, 12, MSG_WAITALL, $from, $port);<br />}