Re: PATCH: (2) Re: FreeBSD compatability feature request

[Peter Stephenson <pws@xxxxxxx>]

Vincent Stemen wrote:
> I also don't have a full understanding of all aspects of signal
> handling, but it looks to me like in order to implement trapsasync
> mode, it would involve using the WNOHANG option to waitpid() or
> wait3() or wait4() to periodically check the child status without
> blocking the parent until the child exits.  That way I am guessing you
> can immediately receive signals in the parent and kill the child,
> exit, or whatever.  My question is, does that affect the child's
> ability to be interactive.

Some parts of the shell do use this, but in the main part where the
shell waits for a job (zwaitjob() in jobs.c) it simple calls
sigsuspend(), installing a particular signal mask.  What's more, there's
already a loop, so it's reasonably safe about bogus signals.  It looks
likes it's probably not too hard to alter, except that signals are tricky
things.

-- 
Peter Stephenson <pws@xxxxxxx>                  Software Engineer
CSR Ltd., Science Park, Milton Road,
Cambridge, CB4 0WH, UK                          Tel: +44 (0)1223 692070


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