On Sat, Aug 15, 2020 at 07:24:01AM -0400, Mouse wrote: > >>> What I observe is that a process that explicitly ignores SIGCHLD > >>> (SIG_IGN), then forks a child which exits, when wait()ing for the > >>> child, gets ECHILD (i.e., wait returns -1 and errno is ECHILD). > >> And the ECHILD return is delayed until all children have terminated > > Huh, I hadn't realized (or expected) that. So I guess it's wrong to > > implement this by just detaching the child up front...? > > I would say so, especially since that would mean the child's parent is > no longer the process that forked it (which could break other use > cases).
That depends on how you implement detaching, but I suppose ultimately it's important for getppid() to revert to 1 at the point the parent exits (neither before, nor after, nor never) so some kind of linkage needs to remain. Bah. I guess it's time to invent yet another different interface to fork-and-really-detach. > > I'm guessing also then that it's the signal setting when the child > > exits that matters; I had always thought it was the signal setting > > when the child was forked. > > Oh, interesting point. > > Yes, in a test I just did [...] Yup, me too. -- David A. Holland dholl...@netbsd.org
