Function GetMaxPlayers returns the maximum number of players that can join the server, as set by the server variable 'maxplayers' in server.cfg.
This function can not be used in place of MAX_PLAYERS. It can not be used at compile time (e.g. for array sizes). MAX_PLAYERS should always be re-defined to what the 'maxplayers' var will be, or higher. See MAX_PLAYERS for more info.

(This function has no parameters.)

Return Values:
The maximum number of players that can join the server.

new str[128];
format(str, sizeof(str), "There are %i slots on this server!", GetMaxPlayers());
SendClientMessage(playerid, 0xFFFFFFFF, s);

Related Functions
The following functions may be useful, as they are related to this function in one way or another.