Releases units back to a semaphore.
The function semaphore-release
releases count units back to the semaphore sem.
It atomically increments the semaphore's unit count by count (which defaults to 1).
The returned flag is true if any other thread was waiting for the semaphore and false otherwise
semaphore
make-semaphore
semaphore-acquire
semaphore-count
semaphore-wait-count
Counting semaphores
LispWorks User Guide and Reference Manual - 20 Sep 2017