$address = "/tmp/socket.sock";

if (($sock = socket (AF_UNIX, SOCK_STREAM, 0)) < 0) {
    echo "socket() failed: reason: " . strerror ($sock) . "\n";
	exit;
}

if (($ret = bind ($sock, $address)) < 0) {
    echo "bind() failed: reason: $ret " . strerror ($ret) . "\n";
	exit;
}

===========
I get: bind() failed: reason: -22 Invalid argument