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Re: Somewhat off-topic, but hard to find better portability people.

From: Ralf Wildenhues
Subject: Re: Somewhat off-topic, but hard to find better portability people.
Date: Wed, 17 Sep 2008 08:59:05 +0200
User-agent: Mutt/1.5.18 (2008-05-17)

Hello Peter,

* Peter Seebach wrote on Wed, Sep 17, 2008 at 06:12:40AM CEST:
> I am looking for systems on which the following *do not* work:
> unset

Quoting the Autoconf manual:
| `unset'
|      In some nonconforming shells (e.g., Bash 2.05a), `unset FOO' fails
|      when `FOO' is not set.  Also, Bash 2.01 mishandles `unset MAIL' in
|      some cases and dumps core.

So look for systems with those bash versions.

> "$@" (expanding to null, not an empty string, when no positional parameters)

systems are listed for this, too:

| `$@'
|      One of the most famous shell-portability issues is related to
|      `"$@"'.  When there are no positional arguments, Posix says that
|      `"$@"' is supposed to be equivalent to nothing, but the original
|      Unix version 7 Bourne shell treated it as equivalent to `""'
|      instead, and this behavior survives in later implementations like
|      Digital Unix 5.0.

> (As is so often the case, "portable" is not exactly a boolean; what I want to
> be able to do is tell people not just that there exists a machine where
> one of these doesn't work, but what it might be, so they can make informed
> decisions about it.)

Sure.  If you're missing systems mentioned in the Autoconf manual,
then they should be added.  Typically, if we find a newer system
that still exposes an old bug, we list it.


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