DosResetEventSem resets an event semaphore, causing all threads that subsequently call DosWaitEventSem to be blocked. It also returns the post count for the semaphore. The post count is the number of times that DosPostEventSem has been called since the last time the semaphore was in the reset state.

This function can be called by any thread in the process that created the semaphore. Threads in other processes can also call this function, but they must first gain access to the semaphore by calling DosOpenEventSem.