Nonzero indicates success. Zero indicates failure. To get extended error information, call GetLastError.

The state of a manual-reset event object remains signaled until it is set explicitly to the nonsignaled state by the ResetEvent function. Any number of waiting threads, or threads that subsequently begin wait operations for the specified event object by calling one of the wait functions, can be released while the object's state is signaled.

The state of an auto-reset event object remains signaled until a single waiting thread is released, at which time the system automatically sets the state to nonsignaled. If no threads are waiting, the event object's state remains signaled.

Each object type, such as memory maps, semaphores, events, message queues, mutexes, and watchdog timers, has its own separate namespace. Empty strings, "", are handled as named objects. On Windows desktop-based platforms, synchronization objects all share the same namespace.

Reference