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

[Eli Zaretskii <eliz@gnu.org>]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: Roland Winkler <Roland.Winkler@physik.uni-erlangen.de>,  lekktu@gmail.com,  emacs-devel@gnu.org
> Date: Sun, 21 Dec 2008 21:45:06 -0500
> 
> The primitives should ensure that what they return forms a forest.

You mean a tree.

> I.e. under POSIX, they should treat a "ppid == 0" as meaning that
> there's no parent (i.e. the data returned to Elisp should never say "the
> parent is process 0" but should instead say "this process doesn't have
> a parent").

For me, code that calls process-tree-root-p (say) is much more
self-explanatory than a test for a missing parent pid attribute.  It
is also more reliable, since ppid attribute could be missing for some
other reason, like failure to access the attribute.

So I don't understand why you insist on the above, please feel free to
explain what advantages do you see there.

Btw, is the above really mandated by Posix?  Any references to that?