If a thread attempts a P operation when a counting semaphore has been decremented to zero, ________.
A) the thread obtains a resource from the pool and decrements the semaphore to -1
B) the thread obtains a resource from the pool and the semaphore remains equal to 0
C) the thread must wait until a resource is returned to the pool by a V operation
D) the thread returns a resource to the pool and increments the semaphore to 1

Question

Quizplus · Accepted Answer

When a semaphore is at zero, a P operation (wait) will cause the thread to block until another thread performs a V operation (signal) to increment the semaphore, indicating a resource is available.

If a Thread Attempts a P Operation When a Counting