Path: utzoo!attcan!uunet!virtech!cpcahil
From: cpcahil@virtech.uucp (Conor P. Cahill)
Newsgroups: comp.unix.internals
Subject: Re: shmat() & shmdt() questions.
Message-ID: <1990Sep17.104439.8763@virtech.uucp>
Date: 17 Sep 90 10:44:39 GMT
References: <13612@hydra.gatech.EDU> <452@cfa.HARVARD.EDU>
Reply-To: cpcahil@virtech.UUCP (Conor P. Cahill)
Organization: Virtual Technologies Inc., Sterling VA
Lines: 18

In article <452@cfa.HARVARD.EDU> wyatt@cfa.HARVARD.EDU (Bill Wyatt,OIR) writes:
>
>Yes. One thing that bugs me is that there's apparently no way (at
>least under Ultrix) to mark a segment for deletion when its reference
>count goes to zero. As with semaphores and message queues, the useful
>file system semantics were not implemented, making these a pain to
>control. They are very useful, though, so I continue to use them.

Have you tried using shmctl(.. IPC_RMID..) to do this?  The feature of
not deleting the item until count goes to zero is usually not documented
for shared memory segments (although it is not only not-documented for
messages & semaphores, it doesn't work for them).  Try it, you may be
pleasantly suprised.

-- 
Conor P. Cahill            (703)430-9247        Virtual Technologies, Inc.,
uunet!virtech!cpcahil                           46030 Manekin Plaza, Suite 160
                                                Sterling, VA 22170