Date: Wed, 6 Apr 2005 14:22:31 +0900 From: Till Plewe <till@score.is.tsukuba.ac.jp> To: freebsd-questions@freebsd.org Subject: Re: flockfile does not work with stdout (on Message-ID: <20050406052231.GA99716%till@score.is.tsukuba.ac.jp>
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On Tue, Apr 05, 2005 at 10:40:49PM -0500, Dan Nelson wrote:
> In the last episode (Apr 06), Till Plewe said:
> > How can I control the output of processes (forked from a single
> > process) all writing to the same file?
> > f{un,}lockfile(file) seems to work unless file=stdout.
>
> If they are still the same process image (i.e. no execs), you could
> mmap some ANONYMOUS|SHARED memory and wait on a flag byte with
> atomic_cmpset(). Actually, writing to stdout should be atomic for most
> writes (I have never seen gcc output garbled when doing parallel makes
> for example).
>
The life span of each process is quite short (<0.001s) and the system load
is fairly high (~40)
Thanks, your suggestion works. In fact flockfile also works if I
use cons25 instead of {x,ml,...}term. So the culprit may be X.
- Till
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