Win32 introduces a set of functions which will allow developers to identify “hot keys”, which are key combinations that deserve special attention by the system. When one of these keys is hit, and recognized by the system, a WM_HOTKEY message is placed at top of a given thread's input queue, bypassing existing queued input.
Apps use these functions if they want notification of an event independent of their input queue. For example, this function will allow an app to recognize a control-c hot key (a keyboard based cancel or stop action) independent of existing queued key strokes. See RegisterHotKey, UnregisterHotKey, and the WM_HOTKEY window message in the programmers reference.