P/V using SysV semop(2)

Christoph Kuenkel ckl at uwbln.UUCP
Wed Aug 24 23:45:43 AEST 1988


I just tried to implement Disjkstra's P/V semaphore operations using
system V's semops.  what i found on three different SysV R.2 ports was
that mutual exclusion was ok but the order of entrance into the critical
section enclosed into P/V was ``by random'' (probably by order of kernel
process slot, which is roughly equivalent to ``by random'').

I implemented it using an array of 1 semaphore and a value of -1 for
sem_op.  

As far as i understand, the documentations does not specify anything at all.
i cant believe it. is it impossible to implement P/V without starvation?
-- 
Christoph Kuenkel/UniWare GmbH       Kantstr. 152, 1000 Berlin 12, West Germany
ck at tub.BITNET                ckl at uwbln             {unido,tmpmbx,tub}!uwbln!ckl



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