A Handy Thread Synchronization Object Chart

The following chart summarizes how the various kernel objects behave with respect to thread synchronization.

Object When Nonsignaled When Signaled Successful Wait Side Effect Process While process is still active When process terminates (ExitProcess, TerminateProcess) None Thread While thread is still active When thread terminates (ExitThread, TerminateThread) None Job When job's time has not expired When job time expires None File When I/O request is pending When I/O request completes None Console input No input exists When input is available None File change notifications No files have changed When file system detects changes Resets notification Auto-reset event ResetEvent, PulseEvent, or successful wait When SetEvent/PulseEvent is called Resets event Manual-reset event ResetEvent or PulseEvent When SetEvent/PulseEvent is called None Auto-reset waitable timer CancelWaitableTimer or successful wait When time comes due (SetWaitableTimer) Resets timer Manual-reset waitable timer CancelWaitableTimer When time comes due (SetWaitableTimer) None Semaphore Successful wait When count > 0 (ReleaseSemaphore) Decrements count by 1 Mutex Successful wait When unowned by a thread (ReleaseMutex) Gives ownership to thread Critical section (user-mode) Successful wait ((Try)EnterCriticalSection) When unowned by a thread (LeaveCriticalSection) Gives ownership to thread

Interlocked (user-mode) functions never cause a thread to be unschedulable; they alter a value and return immediately.