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

[Eli Zaretskii]

> From: Stefan Monnier <address@hidden>
> Cc: address@hidden,  address@hidden,  address@hidden
> Date: Mon, 22 Dec 2008 07:23:05 -0500
> 
> To me the definition of "root" is "has no parent", so the two are
> equivalent.

Same here.  But "having no parent" and "found zero in /proc/NNN/stat"
is not necessarily the same.

> I could live with a predicate process-tree-root-p, but I'd expect it
> to just check for the absence of a parent.

Me too.  However, that check is OS-dependent, so I don't think it
should be in Lisp.

> > It is also more reliable, since ppid attribute could be missing for
> > some other reason, like failure to access the attribute.
> 
> And what would your process-tree-root-p say in that case?

It depends on the OS.

> On my GNU/Linux system, 0 is not a process, so a ppid of 0 is not
> a parent but rather the mark of the absence of a parent.

Sounds like this isn't true on FreeBSD as well, not only on
MS-Windows.