Reduce cpu usage

[dtfinch]

Before, it would max out a cpu core at 100% while waiting (undesirable if what it's waiting on needs the full cpu). Adding a 1ms sleep reduced its usage to about 1-2% in my case.

[AvianFlu]

Yeah, I was afraid of that.

Can you try c416218 ? I think that it might actually be the correct solution to this (it will just block the parent completely until the child exits), and would be an improvement over just adding a timeout.

[dtfinch]

Changing WNOHANG to 0 was the first thing I tried, but it was returning prematurely (which seems to contradict the waitpid documentation), so I went with the sleep instead.

[andrasq]

I was going to ask for the same thing -- getting rid of the busy-wait.

The blocking waitpid() must still be looped, because a received signal will unblock the wait (even if handled). The fix is to check the return status and block again, something like:

do {
    r = waitpid(child, &status, 0);
} while (r == 0);