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From: Patrick Plattes <patrick@erdbeere.net>
To: linux-kernel@vger.kernel.org
Subject: semaphore understanding: sys_semtimedop()
Date: Mon, 16 May 2005 22:17:04 +0200	[thread overview]
Message-ID: <20050516201704.GA9836@erdbeere.net> (raw)

Hello,

i have a question about this little code snippet, found in
sys_semtimedop() (ipc/sem.c):

        for (sop = sops; sop < sops + nsops; sop++) {
                if (sop->sem_num >= max)
                        max = sop->sem_num;
                if (sop->sem_flg & SEM_UNDO)
                        undos++;
                if (sop->sem_op < 0)
                        decrease = 1;
                if (sop->sem_op > 0)
                        alter = 1;
        }
        alter |= decrease;

The variable decrease will never be used again in this 
function, so why this intricate code? Isn't this much easier and works
also:

        for (sop = sops; sop < sops + nsops; sop++) {
                if (sop->sem_num >= max)
                        max = sop->sem_num;
                if (sop->sem_flg & SEM_UNDO)
                        undos++;
                if (sop->sem_op != 0)
                        alter = 1;
        }

Maybe i'm totally wrong, so please correct me and don't shoot me up,
'cause i'm not a os developer.

Thanks,
  Patrick

             reply	other threads:[~2005-05-16 20:23 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-05-16 20:17 Patrick Plattes [this message]
2005-05-22  5:21 ` semaphore understanding: sys_semtimedop() randy_dunlap
2005-05-22  6:49   ` Manfred Spraul

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