Date: Tue, 5 Apr 2005 22:40:49 -0500 From: Dan Nelson <dnelson@allantgroup.com> To: freebsd-questions@freebsd.org Subject: Re: flockfile does not work with stdout (on Message-ID: <20050406034049.GI64927@dan.emsphone.com> In-Reply-To: <20050406022116.GB99381%till@score.is.tsukuba.ac.jp> References: <20050406022116.GB99381%till@score.is.tsukuba.ac.jp>
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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).
--
Dan Nelson
dnelson@allantgroup.com
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