SYS$ASCEFC (OpenVMS) SYS$ASCEFC (OpenVMS)
NAME
semget - returns a semaphore ID
SYS$ASCEFC - Associate with common event cluster
EXPLAINATION
The Digital UNIX function semget is similar to the OpenVMS SYS$ASCEFC
system service in that they are both used to create a process synchro‐
nization object. Semaphores created by semget area always permanent,
global among processes, and are created uninitalized. The semctl func‐
tion can be used to give values to a semaphore. Digital UNIX sempa‐
hores are counting semaphores, so unlike event flags they may have any
nonnegative value. A single event flag can be emulated in Digital UNIX
by using the semaphore as a binary semaphore (only using the 1 and 0
values). Semaphores may be grouped into semaphore sets of varying size
as specified by the second argument to semget. Since semaphores are
permanent, they must be explicitly removed or the maximum number of
semaphores for the system may be reached. The ipcs command lists the
semaphores currently in use.
RELATED INFORMATION
Digital UNIX Functions:
semop(2), semget(2), semctl(2), ipcs(1) delim off
SYS$ASCEFC (OpenVMS)
