public function createGuid()
    {
        return sprintf('%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
            mt_rand(0, 0xffff), mt_rand(0, 0xffff),
            mt_rand(0, 0xffff),
            mt_rand(0, 0x0fff) | 0x4000,
            mt_rand(0, 0x3fff) | 0x8000,
            mt_rand(0, 0xffff), mt_rand(0, 0xffff), mt_rand(0, 0xffff)
        );
    }
public function createGuid()
    {
        return sprintf('%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
            mt_rand(0, 0xffff), mt_rand(0, 0xffff),
            mt_rand(0, 0xffff),
            mt_rand(0, 0x0fff) | 0x4000,
            mt_rand(0, 0x3fff) | 0x8000,
            mt_rand(0, 0xffff), mt_rand(0, 0xffff), mt_rand(0, 0xffff)
        );
    }
public function createGuid ( ) { return sprintf ( '%04x%04x-%04x-%04x-%04x-%04x%04x%04x' , mt_rand ( 0 , 0xffff ) , mt_rand ( 0 , 0xffff ) , mt_rand ( 0 , 0xffff ) , mt_rand ( 0 , 0x0fff ) | 0x4000 , mt_rand ( 0 , 0x3fff ) | 0x8000 , mt_rand ( 0 , 0xffff ) , mt_rand ( 0 , 0xffff ) , mt_rand ( 0 , 0xffff ) ) ; }
Creates a guid using UUID v4 based on RFC 4122

@see http://tools.ietf.org/html/rfc4122#section-4.4
@see http://www.php.net/manual/en/function.uniqid.php#94959
@return string a uuid-v4
Creates a guid using UUID v4 based on RFC 4122