Date: Sun, 7 Sep 1997 13:39:17 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: joerg_wunsch@uriah.heep.sax.de Cc: freebsd-hackers@FreeBSD.ORG, jamil@counterintelligence.ml.org Subject: Re: SIGCLD Message-ID: <199709071339.GAA06816@usr09.primenet.com> In-Reply-To: <19970907091757.ST01979@uriah.heep.sax.de> from "J Wunsch" at Sep 7, 97 09:17:57 am
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> By explicitly setting the signal handler to SIG_IGN, you tell the system > that you aren't interested in the death of your child, and you won't > get zombies. > > This of course is a terrible crock, but was the only way to express > this in SVR3. SVR4 and Posix use the option SA_NOCLDWAIT in > sigaction(2) to express this wish. FreeBSD doesn't implement this > option (yet). Are you sure about this? The only POSIX defined SA_ flag I know about is SA_NOCLDSTOP, which prevents SIGCHLD when child processes are stopped, but still generates it for child process death. While we are on the subject, SA_NODEFER is kind of wierd, and BSDI compatability is impossible with SA_DISABLE being 0x0004 on BSDI (which disables the taking of signals on an alternate stack). I understand the need for SA_RESETHAND; it lets you use the general underlying "POSIX + flag extensions" signal implementation to get backward compatability with SVR3/SVR2, etc.. But shouldn't any FreeBSD-only flags really be higher in the flag space, like the SA_USERTRAMP? Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.
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