#define IDM_EXIT           100
#define IDM_DEMO           200
#define IDM_ABOUT          301

#define DLG_VERFIRST        400
#define DLG_VERLAST         404

LRESULT CALLBACK WndProc  (HWND, UINT, WPARAM, LPARAM);
LRESULT CALLBACK About    (HWND, UINT, WPARAM, LPARAM);