[NumLock]

Код:

VOID mouse_event(
    DWORD dwFlags,	// flags specifying various motion/click variants
    DWORD dx,	// horizontal mouse position or position change
    DWORD dy,	// vertical mouse position or position change
    DWORD dwData,	// amount of wheel movement
    DWORD dwExtraInfo 	// 32 bits of application-defined information
   );