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From r..@covalent.net
Subject Re: SYSV Semaphores.
Date Sun, 31 Dec 2000 18:09:45 GMT

> > There is another problem with SysV semaphores that needs to be seriously
> > considered.  If we kill ourselves off incorrectly, we will keep the
> > semaphore.
> 
> this is not a problem with sysv semaphores.  they are kernel objects.
> the kernel cleans them up on process exit (assuming SEM_UNDO is set, as we
> do -- iirc the limitation on solaris is a static number of undo records in
> the kernel).
> 
> this is a problem with pthreads mutexes.  these are userland objects that
> the kernel has no record of.

Hmmm...  We have seen some platforms not removing the semaphores
though.  I believe on FreeBSD, that if we didn't clean the semaphores,
then the kernel wasn't doing it for us.

Ryan

_______________________________________________________________________________
Ryan Bloom                        	rbb@apache.org
406 29th St.
San Francisco, CA 94131
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