There''s no difference except to show that you''re using openGL right?

there CAN be a difference.
Because some OS treat different number different(some thing like a int on a apple may use 8 bits and on windows use 4 bits (not true valuse just for demo purposes)) opengl has its own defined data types so no mater what system u use its treated the same. thus if ure intendong on cross platforming a project use the gl defined data types

Ahh I see, thanks

Heh, I have always wondered that, but never really bothered to ask. Pretty clever.

actually, if you look in the opengl header file, you''ll see

typedef float GLfloat;