Proper way to access executable's "environment"?

[David Wolfskill]

On Mon, May 27, 2013 at 05:43:13AM +0700, Erich Dollansky wrote:
> ...
> > piewm's twm.c declares main as:
> > 
> > int
> > main(int argc, char **argv, char **environ)
> > {
> 
> I use this concept since decades but with different names. Could it be
> a problem of overlapping names?
> ...

It was pointed out to me that -- other than assigning "Environ =
environ" -- the code in piewm's twm.c didn't actually use the values of
environ or Environ.  [Thanks, Stefan!]

Elsewhere, there is a putenv() implementation for environments that
lack it, and the code uses getenv(), as well.

Doing a few more comparisons with twm.c from tvtwm and from twm itself;
I have a few more observations:

* tvtwm's twm.c is more recent than that of piewm:
  - * $XConsortium: twm.c,v 1.124 91/05/08 11:01:54 dave Exp $
  + * $XConsortium: twm.c,v 1.111 90/03/23 13:23:34 jim Exp $

* twm's twm.c has a copyright block dated 2005 from Hitachi, Ltd.

* Merely inserting the "#include <stdlib.h>" in piewm's twm.c appears
  to be a minimal effective change: Once that's done, the SIGSEGV goes
  away.

* Neither tvtwm's nor twm's twm.c has the "#include <stdlib.h>" (and
  neither gets a SIGSEGV).

* As Stefan pointed out, I was able to completely remove the references
  to both "environ" and "Environ" from piewm's twm.c; the result builds
  and runs without problem.

* tvtwm's twm.c has these environ and Environ variables (and, as above,
  lacks the "#include <stdlib.h>" and doesn't get the SIGSEGV).

* twm's twm.c lacks the environ and Environ variables (and main() is
  defined as a function that takes but 2 arguments).

I suspect that I'm failing to understand at least part of what's causing
the actual problem in piewm.

Peace,
david
-- 
David H. Wolfskill				david at catwhisker.org
Taliban: Evil men with guns afraid of truth from a 14-year old girl.

See http://www.catwhisker.org/~david/publickey.gpg for my public key.
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