The function make-semaphore
returns a new semaphore for use with semaphore-acquire and semaphore-release. The unit count is initialized to count, which defaults to 1. If name is supplied, the semaphore will have that name. If name is not supplied, the semaphore will be given a unique anonymous name.
semaphore
semaphore-acquire
semaphore-count
semaphore-name
semaphore-release
semaphore-wait-count
Counting semaphores
LispWorks User Guide and Reference Manual - 20 Sep 2017