Code review comment for lp:~afrantzis/unity-system-compositor/no-external-spinner-zombie-processes

On Friday, 10 July 2015 6:21:03 PM AEST, Alexandros Frantzis wrote:
>> Simply calling wait() or waitpid() at the right times will avoid zombies.
>> That's what "zombie process" means -- that the parent has not
>> called wait() yet.
>
> That was my initial approach, but the problem with this is that
> waitpid() blocks USC for a little bit in the best case, and can
> block forever if for whatever reason the external spinner
> happens to not respond to our signals (e.g. it has hung).

The canonical way of handling this is a SIGCHILD handler; that way you only
ever call non-blocking waitpid.

That said, double-forking should work, too.

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