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semaphoremodule provides a general use
- This class represents a general counting semaphore as concieved by Edsger Dijkstra. As per Mesa type monitors however, "signal" has been replaced with "notify" to indicate that control is not transferred to the waiter when a notification is sent.
- Initializes a semaphore object with the specified initial
countfor the semaphore.Throws:SyncError on error.
- Wait until the current count is above zero, then atomically decrement the count by one and return.Throws:SyncError on error.
- Suspends the calling thread until the current count moves above zero or until the supplied time
periodhas elapsed. If the count moves above zero in this interval, then atomically decrement the count by one and return
true. Otherwise, return
The time to
periodmust be non-negative.Throws:SyncError on error.Returns:
trueif notified before the timeout and
- Atomically increment the current count by one. This will
notifyone waiter, if there are any in the queue.Throws:SyncError on error.
- If the current count is equal to zero, return. Otherwise, atomically decrement the count by one and return
true.Throws:SyncError on error.Returns:
trueif the count was above zero and