Where do you find function definitions??

[IconoclastDX]

I can find the declaration but cant find how they work (definition). e.g. FMax() is used all over the place. It take two floats as arguments and returns a float. I assumed of I just kept backing up through the inheritance hierarchy I would everntually find the code that lays out what FMax() does with those two floats, but all i can find is the following line in "Object"

native(245) static final function float FMax ( float A, float B );

Is there some kind of header file or something Im suppose to be looking in or am I just so far in left feild it's laughable?

Thanks