#define IDM_EXIT           100
#define IDM_DEMO           200
#define IDM_ABOUT          300

#define DLG_VERFIRST        400
#define DLG_VERLAST         404

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