From: Curt Hibbs <ml.chibbs@...>
Date: 2006-08-01T01:43:58+09:00
Subject: Re: Environment variables with empty value missing from ENV?

On 7/31/06, nobu@ruby-lang.org <nobu@ruby-lang.org> wrote:
> Hi,
>
> At Mon, 31 Jul 2006 22:57:03 +0900,
> Curt Hibbs wrote in [ruby-talk:205183]:
> > > Win32 API GetEnvirionmentVariable() doesn't tell if the
> > > variable is empty or unset.  Actually, there is no way to set
> > > an empty environment variable by cmd.exe.  I'm not sure if it
> > > is misfeature or restriction by design.
> >
> > As far as I know, Windows uses an empty env. var. as a signal to
> > delete that env. var.
>
> In accurate, Windows allows an empty env var, but cmd.exe (and
> of course, command.com) uses it to delete it.
>
>  $ ./ruby -e 'ENV["FOO"]="";p system("cmd /c set FOO")'
>  FOO=
>  true
>
> And, usa has fixed the empty value issue today.
>
> --
> Nobu Nakada

Ok... thanks!

Curt