<defunct> processes (was Re: Trouble killing processes in SysV/AT)

[Bob Lenk]

> I have noticed a similar phenomenon with BSD4 - I wrote a program once that
> did lots and lots of popen("command", "w") calls. I fired it up background,
> and a minute later did a "ps ag" to see what was happening. My process was
> there, but so were about 40 processes marked STAT == Z, COMMAND == <defunct>.

Lots of folks have correctly explained that the parent must call
wait(2) or an equivalent to clean up zombies.  It's important to note
that the way to do this following popen(3) is with pclose(3).

		Bob Lenk
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