Re: SIGCHLD handler in Postgres C function.

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Bill Studenmund <wrstuden(at)zembu(dot)com>, Tatsuo Ishii <t-ishii(at)sra(dot)co(dot)jp>, spshealy(at)yahoo(dot)com, pgsql-hackers(at)postgresql(dot)org
Subject: Re: SIGCHLD handler in Postgres C function.
Date: 2001-07-30 23:41:06
Message-ID: 200107302341.f6UNf6t07156@candle.pha.pa.us
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> Bill Studenmund <wrstuden(at)zembu(dot)com> writes:
> > Looking at source on the web, I found:
>
> > kernel/signal.c:1042
>
> > * Note the silly behaviour of SIGCHLD: SIG_IGN means that the
> > * signal isn't actually ignored, but does automatic child
> > * reaping, while SIG_DFL is explicitly said by POSIX to force
> > * the signal to be ignored.
>
> Hmm, interesting. If you'll recall, the start of this thread was a
> proposal to change our backends' handling of SIGCHLD from SIG_IGN to
> SIG_DFL (and get rid of explicit tests for ECHILD). I didn't quite see
> why changing the handler should make a difference, but above we seem to
> have the smoking gun.
>
> Which kernel, and which version, is the above quote from?

The auto-reaping is standard SysV behavior, while BSD is really ignore.
See the Steven's Unix Programming book for more info.

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