Lock or unlock all message queues except the
one associated with the current thread.
This is the only value accepted for this parameter.
Lock (BOOL) - input
Lock indicator:
TRUE
Lock the message queue or queues, except the
current thread's message queue. This is to prevent all threads from generating
any more "send" messages to other threads. All mouse and keyboard inputs
will be given to the current thread.
FALSE
Unlock the message queue or queues that
were locked by a previous call to WinLockInput with Lock set to TRUE.