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Date:      Sat, 30 Nov 2002 14:53:12 -0800
From:      Terry Lambert <tlambert2@mindspring.com>
To:        Daniel Eischen <eischen@pcnet1.pcnet.com>
Cc:        Brian Smith <dbsoft@technologist.com>, "current@FreeBSD.ORG" <current@FreeBSD.ORG>
Subject:   Re: Are SysV semaphores thread-safe on CURRENT?
Message-ID:  <3DE94158.142E1B67@mindspring.com>
References:  <Pine.GSO.4.10.10211301204290.27919-100000@pcnet1.pcnet.com>

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Daniel Eischen wrote:
> > No, libc_r doesn't properly handle flock.  Usually, all syscalls
> > that take file descriptors as arguments honor the non-blocking
> > mode of the file if set.  I guess flock(2) doesn't and has its
> > own option to the operation argument (LOCK_NB).
> >
> > I hacked libc_r to periodically check (every 100msecs) the
> > flock.  See if this fixes things:

Same thing I suggested, only I think he was really using fcntl(),
not flock()?

My patch wasn't integral to the library (it was more of a hack),
and my default time was 1S, not 100uS.

Same non-FIFO request ordering, too.  8-(.

I guess the real question is what is an fcntl()/flock() supposed
to do on a blocking call against a non-blocking fd?  I could not
tell, so I punted.

-- Terry

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