From: Vincent Lefevre <vincent@vinc17.org>
To: zsh-users@sunsite.dk
Subject: Re: Unsetting a variable that was not previously set
Date: Fri, 4 Apr 2003 22:41:25 +0200 [thread overview]
Message-ID: <20030404204125.GA7801@greux.loria.fr> (raw)
In-Reply-To: <18642.1049472589@csr.com>
On Fri, Apr 04, 2003 at 17:09:49 +0100, Peter Stephenson wrote:
> I think you're probably right, but it's not completely clear. The page
> you quote explicitly says:
>
> EXIT STATUS
>
> 0
> All name operands were successfully unset.
> >0
> At least one name could not be unset.
>
> Now, if it doesn't exist, it can't be unset,
I don't think that a variable needs to exist in order to be unset.
I think that 'unset' is just a special status (or "value") for the
variable (a bit like 'undef' in Perl). So, we have the following
interpretation:
> but I think by `unset' they mean `rendered such that it is not set
> whether or not it was before', which is your interpretation.
and I think that this is the goal of the following sentence to make
things clear about this problem:
> > "Unsetting a variable or function that was not previously set shall
> > not be considered an error and does not cause the shell to abort."
>
> It doesn't cause the shell to abort currently. The terminology in the
> introduction does suggest `error' is more or less synonymous with
> `non-zero return code', but I can find no normative indication of
> whether this applies to the language used for the special builtins.
I could only find
http://www.opengroup.org/onlinepubs/007904975/utilities/xcu_chap01.html
Under "EXIT STATUS": "Usually, utilities return zero for successful
completion and values greater than zero for various error conditions."
--
Vincent Lefèvre <vincent@vinc17.org> - Web: <http://www.vinc17.org/> - 100%
validated (X)HTML - Acorn Risc PC, Yellow Pig 17, Championnat International
des Jeux Mathématiques et Logiques, TETRHEX, etc.
Work: CR INRIA - computer arithmetic / SPACES project at LORIA
prev parent reply other threads:[~2003-04-04 20:41 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-04-04 15:49 Vincent Lefevre
2003-04-04 16:09 ` Peter Stephenson
2003-04-04 16:29 ` Oliver Kiddle
2003-04-04 20:41 ` Vincent Lefevre [this message]
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