Re: proced: ppid of process ID 0 can be 0

[Stefan Monnier]

>>>> More to the point: even if we could distinguish the "no ppid" from
>>>> "unkown ppid", it's unclear how Elisp code could make use of it.
>>> Lisp code cannot, but a primitive written in C can.
>> 
>> Like what can it do?

> It can differentiate between FreeBSD 4.3 and FreeBSD 7.2 if they use a
> different style of `process root', or between Linux 1.2.X, 2.4.X and
> 2.6.X.  Right now, Emacs sets `system-type' to "berkeley-unix" on more
> than one BSD system.  They might be easier to detect at C level.

That's not what I'm asking.  I'm asking: what can C code (or Elisp code
for that matter) do when the ppid is somehow not found (i.e. there's no
ppid available, but the process might have a parent).


        Stefan