Sending Signals to Zombies

[Richard M. Mathews]

rbj at uunet.UU.NET (Root Boy Jim) writes:

>There seems to be a cultural difference (BSD vs SV) on the
>meaning of sending signals to zombie processes; System V
>allows it while BSD does not.

>What does POSIX say about this, and what are some of the issues?

The most direct statement in POSIX on this is in the rationale rather
than the standard itself; so to make life easy, I'll just quote that.

	In B.3.3.2:
	Existing implementations vary on the result of a kill()
	with pid indicating an inactive process (a terminated
	process that has not yet been waited for by its parent)....
	Since this standard's definition of _process_lifetime_
	covers inactive processes, the [ESRCH] error as described
	is inappropriate in this case.  In particular this means
	that an application cannot have a parent process check
	for termination of a particular child with kill()....
	this can be done reliably with waitpid().

BSD will have to change to become conformant in this regard.

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