I've just started programming with glut and OpenGL and trying some mouse and keyboard events.
There is a callback function glutKeyboardFunc(void (*f)(unsigned char key, int x, int y)) which works fine, but I've also seen a function glutKeyFunc(void (*f), int key), but whenever I use that function it is undefined. I thought that perhaps there is an error in the book I'm using, but when I search for glutKeyFunc() on the Internet I get some examples, though not many, of people using this callback. Is it defined in glut or in some special versions of glut? The book does not explain why it uses it either.