ns_sema - Operate on semaphore-like objects
This command provides a mechanism to manipulate semaphore-like objects but are not inter-process capable like true semaphores. They are actually implemented with a mutex and a counter. The legal options (which may be abbreviated) are:
Initializes a new semaphore whose count is initialized to zero by default or count otherwise. Returns a handle to the semaphore object.
Destroys the semaphore object and frees any resources it was using.
Releases the semaphore object by incrementing the counter by one by default or by count otherwise. The thread will wake any threads blocking on this semaphore when count is equal to one. This is what is commonly referred to as "semaphore up".
Waits for a semaphore object to be greater than zero. Will block the thread until this is true. Decrements the counter by one when the counter is greater than zero. This is what is commonly referred to as "semaphore down".
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