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Date: Sat, 10 May 2003 23:50:41 -0400
From: Christopher Faylor <cgf AT redhat DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: cygipc (and PostgreSQL) XP problem resolved!
Message-ID: <20030511035041.GA20950@redhat.com>
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On Sun, May 11, 2003 at 01:31:12PM +1000, Robert Collins wrote:
>On Sun, 2003-05-11 at 12:37, Christopher Faylor wrote:
>> >>>I can't comment further without looking into the ftok spec again, which
>> >>>I don't have time for right now...
>> >>
>> >>I'm not sure what ftok has to do with whether global atoms are global
>> >>or not, however.
>
>Because you where suggesting the use of global atoms in ftok() - or did
>I get confused? 

One of us must be.  It is a given that ftok has to be consistent across
logins.  Otherwise a process which is trying share Sys V semaphores will
not be able to share the same ids (which are usually based on ftok)
among different processes.

As you noted, since global atoms can't do that consistently, they are
worthless.  What global atoms do seem to do is provide unique values
across the system.  Unfortunately, one session doesn't seem to be able
to access another session's atoms even if the ids are unique.

cgf

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