Mplay

Mplay is the gamemaker multiplayer function. It is widely agreed that it should be deprecated, but this is not in the immediate plans of YoYo Games. Many people choose to use DLLs, like 39DLL, that provide similar functionality using updated protocols.

To use Mplay, both the client and the host need to port forward their router. By default, Game Maker uses the ports 2300-2400 and 47624. The port 47624 can actually be changed by the application, as described in this post by GMC User NakedPaulToast: 47624 can be changed in the mplay_init_tcpip statement. Typically the host does a: mplay_init_tcpip(""); and the joiners do: mplay_init_tcpip("123.123.123.123"); To change the 47624 to 10000, the respective statements would become: mplay_init_tcpip(":10000"); mplay_init_tcpip("123.123.123.123:10000");

Fuctions
mplay_connect_status mplay_data_mode mplay_data_read mplay_data_write mplay_end mplay_init_ipx mplay_init_modem mplay_init_serial mplay_init_tcpip mplay_ipaddress mplay_message_clear mplay_message_count mplay_message_id mplay_message_name mplay_message_player mplay_message_receive mplay_message_send mplay_message_send_guaranteed mplay_message_value mplay_player_find mplay_player_id mplay_player_name mplay_session_create mplay_session_end mplay_session_find mplay_session_join mplay_session_mode mplay_session_name mplay_session_status