try_wait_event — Lock an event synchronization object only if it is unlocked.
try_wait_event behaves identically to
that it does not block the calling thread when waiting until the object is
signaled but returns immediately. The state of the event before entering
try_wait_event is returned in
Busy. 1 indicates
that the event was nonsignaled before calling
0 that the event was signaled.
Event synchronization object.
Object already locked?
If the event handle is valid, the operator
returns 2 (H_MSG_TRUE). If necessary, an exception is raised.