P2P messages are an important mechanism when creating more advanced games. If you know the 39dll system, this is an advanced version of plain "packages."
Every player-to-player (P2P) message starts with an ID. This can be an integer ranging 0 to 255. The ID is a simple way of distinguishing different types of P2P messages. It's a good practise to define constants for this. Your code will get very messy otherwise.
You can send a P2P message to every player, by supplying a valid player_id. Besides using a player_id objtained by object.player_id or [gms_other_find] you can also provide the special constant to_server. This will send the P2P message to the server instead of a player.
Last message on 6 Apr 2015