%semctl() Function

For Windows: Not Supported

The %semctl() function performs semaphore control operations.

Syntax

code = %semctl(sem-ID, semnum, cmd, arg)

Parameter(s)

sem-ID	Semaphore ID returned by a call to %semget().
semnum	Semaphore number in the set, when applicable (depending on cmd).
cmd	Valid values for cmd are defined in sem.h and ipc.h. The commands below are executed with respect to the semaphore specified by sem-ID and semnum:
	getval	Returns the value of semval.
	setval	Sets semval to the value of arg.
	getpid	Returns the value of sempid.
	getncnt	Returns the value of semncnt.
	getzcnt	Returns the value of semzcnt.
	The commands below apply to all semaphores in the set:
	getall	Place all the semaphore values in the arg dimensioned array.
	setall	Set all the semaphores to the values contained in the dimensioned array arg.
	These commands are also available:
	ipc$stat	Return a dimensioned array that contains the various fields of the UNIX semaphore structures. The elements are (see the UNIX system documentation):
		1 sem_perm.uid
		2 sem_perm.cid
		3 sem_perm.guid
		4 sem_perm.gcid
		5 sem_perm.mode
		6 sem_perm.seq
		7 sem_perm.key
		8 sem_nsems
		9 sem_otime
		10 sem_ctime
	ipc$set	Sets the values of the below members of the data structure associated to sem-ID to the first three elements of the array arg:
		1 sem_perm.uid
		2 sem_perm.gid
		3 sem_perm.mode
	ipc$rmid	Removes the semaphore identifier.
arg	Dimensioned array that contains the argument.

Example(s)

include dm,bp,unix.h ipc.h

include dm,bp,unix.h sem.h

* Set initial semaphore values

dim val(3)

mat val=0

%semctl(sem-ID, 0, setall, val)