The GetInputState function determines whether there are mouse-button or keyboard messages in the calling thread's message queue.
BOOL GetInputState(VOID)
This function has no parameters.
If the queue contains one or more new mouse-button or keyboard messages, the return value is nonzero.
If the there are no new mouse-button or keyboard messages in the queue, the return value is zero.
Windows NT: Requires version 3.1 or later.
Windows: Requires Windows 95 or later.
Windows CE: Unsupported.
Header: Declared in winuser.h.
Import Library: Use user32.lib.
Messages and Message Queues Overview, Message and Message Queue Functions, GetQueueStatus