SYS$CLREF (OpenVMS) SYS$CLREF (OpenVMS)
NAME
semop - perform semaphore operations
SYS$CLREF - Clear an event flag
EXPLAINATION
The Digital UNIX semop system call is similiar to the OpenVMS SYS$CLREF
system service in that they both set synchronization values. The semop
function can be called with a negative sem_op operation to decrement
the semaphore. When emulating a binary semaphore and when the sema‐
phore value is 0, a semop operation attempting to decrement a semaphore
would block until another process sets the semaphore to 1 (either by
semop or semctl). Typically, semop with a negative values is used to
indicate a request for a resource.
RELATED INFORMATION
Digital UNIX Functions:
semop(2), semget(2), semctl(2) delim off
SYS$CLREF (OpenVMS)
