Simon Marlow wrote:

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I think this covers most of the useful situations. If you want to do the same thing in both parent and child, or handle in the parent and SIG_DFL in the child: use runProcess. If you want to ignore in the parent and SIG_DFL in the child: use System.Cmd.{system,rawSystem}. To handle in the parent and ignore in the child: unfortunately not directly supported.

As it stands, you can have whatever behaviour you want in the parent: set the desired handling before calling system/rawSystem/runProcess then set it back afterwards.

However, this will cease to be true for system/rawSystem if you change them so that the child restores the handlers to their state upon entry.

I don't understand... is there a typo somewhere above? Perhaps you meant "child" in the first paragraph?

Sorry; I wasn't thinking straight. That part of my message is incorrect; changing the signal handling before calling system/rawSystem won't help, because they force both cases. If they were changed to behave like system(), the caller could determine the *child* behaviour, but that's prone to a race condition, so I doubt that it would be useful in practice.

system/rawSystem now behave almost exactly like system() in C. The only difference is that you can't ignore SIGINT/SIGQUIT in the child, but I can fix that if necessary.

I'm not sure how much it matters; system() isn't really of much use for "real" programs anyhow. -- Glynn Clements