Designing Games with Game Maker - YoYo Games

ty_real,2,ty_real,ty_real);
global.ddd =
external_define('MyDLL.DLL','DoubleString',dll_cdecl,
ty_string,1,ty_string);
}
Now whenever you need to call the functions, you use the following function:
external_call(id,arg1,arg2,...) Calls the external function with the
given id, and the given arguments. You need to provide the correct number of
arguments of the correct type (real or string). The function returns the result
of the external function.
So, for example, you would write:
{
}
aaa = external_call(global.mmm,x,y);
sss = external_call(global.ddd,'Hello');
If you don't need to use the DLL anymore you had better free it.
external_free(dll) Frees the DLL with the given name. This is in
particular necessary if the game should remove the DLL. As long as the DLL is
not freed it cannot be removed. Best do this e.g. in an end of game event.
You might wonder how to make a function in a DLL that does something in the game. For
example, you might want to create a DLL that adds instances of objects to your game. The
easiest way is to let your DLL function return a string that contains a piece of GML code. This
string that contains the piece of GML can be executed using the GML function
execute_string(str,arg0,arg1,...) Execute the piece of code in the
string str with the indicated arguments.