pfsockopen

(PHP 4, PHP 5, PHP 7)

Open persistent Internet or Unix domain socket connection

resource pfsockopen ( string $hostname [, int $port = -1 [, int &$errno [, string &$errstr [, float $timeout = ini_get("default_socket_timeout") ]]]] )

This function behaves exactly as fsockopen() with the difference that the connection is not closed after the script finishes. It is the persistent version of fsockopen().