public enum SendMessageTimeoutFlags : uint
The function returns without waiting for the time-out period to elapse if the receiving thread appears to not respond or "hangs."
Prevents the calling thread from processing any other requests until the function returns.
The function should return 0 if the receiving window is destroyed or its owning thread dies while the message is being processed.
The calling thread is not prevented from processing other requests while waiting for the function to return.
The function does not enforce the time-out period as long as the receiving thread is processing messages.