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From Jim Jagielski <...@jaguNET.com>
Subject Re: Using semaphore locking
Date Mon, 08 Sep 1997 20:34:19 GMT
Pierre-Yves Kerembellec wrote:
> 
> Le [Mon, 8 Sep 1997 11:36:43 -0400 (EDT)], Jim Jagielski ecrivait :
> 
> > I've only recently looked at the semaphore locking and have a few idea
> > to make it more portable. Basically, as we do with shared memory,
> > we can setup the semaphore to automnatically be deleted (IPC_RMID)
> > when there are no more processes accesing it, rather than using
> > a atexit() hack.
> 
> Ahem, as mentionned by Dean ("what a lame interface !"), the IPC_RMID
> is not used for that purpose ... indeed, you have no mean to delete a
> semaphore when the last process exit ...
> 

Ahem,

     IPC_RMID
	 Remove the semaphore identifier specified by semid from
	 the system and destroy the set of semaphores and data
	 structure associated with it.  This command can only be
	 executed by a process that has an effective user ID
	 equal to either that of superuser or to the value of
	 sem_perm.uid in the data structure associated with
	 semid.  The identifier and its associated data
	 structure are not actually removed until there are no
	 more referencing processes.  See ipcrm(1), and ipcs(1).


-- 
====================================================================
      Jim Jagielski            |       jaguNET Access Services
     jim@jaguNET.com           |       http://www.jaguNET.com/
            "Look at me! I'm wearing a cardboard belt!"

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