basic.%semop C Function/BASIC Program


Command basic.%semop C Function/BASIC Program
Applicable release versions: AP/Unix, AP 6.1
Category BASIC Program (486)
Description performs an array of semaphore operations on a set of semaphores.
semid Semaphore identifier returned by a call to semget().

sops Array of semaphores operation. "sops" is a "nsops" by 3 two-dimension array. Each row in the array is the equivalent of a "sops" structure, as defined in the Unix Programmer Reference Guide. In other words, sops(i,1) is sem_num, sops(i,2) is sem_op, sops(i,3) is sem_flg. See the Unix documentation for the description of these fields.

nsops Number of rows in the "sops" array.
Syntax code=%semop( semid, sops, nsops )
include dm,bp,unix.h ipc.h
include dm,bp,unix.h sem.h
include dm,bp,unix.h mode.h

* Get a set of 4 semaphores
semid=semget( key, 4, IPC$CREAT )
if semid<0 then
    crt "semget error=":system(0)

* Wait for: (1st sem >=1) and (2nd sem >=2)
dim sops(2,3)
* - Set 1st condition
sops(1,1)=0           ;* 1st sem
sops(1,2)=-1          ;* Wait until can do -1
sops(1,3)=0           ;* No flag
* - Set 2nd condition
sops(1,1)=1           ;* 2nd sem
sops(1,2)=-2          ;* Wait until can do -2
sops(1,3)=0           ;* No flag
n=semop( semid, sops, 2)
if n<0 then
    crt "semop error=":system(0)
Related basic.%semget