On a system shutdown, each message queue normally posts a WM_QUIT message. An application can then handle this message in one of the three ways:

• Destroy its message queue using WinDestroyMsgQueue (hmq).

• Call WinCancelShutdown (hmq, TRUE) to prevent the current thread's event queue from receiving the WM_QUIT messages when the system is shut down. This does not stop other threads from receiving this message.

• Call WinCancelShutdown (hmq, FALSE) to remove all pending WM_QUIT messages from the current thread's event queue but allow future WM_QUIT messages to be posted.

Either way, the system can proceed to the next queue.