Re: unset variables, was Re: please correct my ugly hack

[Stepan Kasal]

Hello,

On Thu, Jun 02, 2005 at 11:35:20PM -0700, Paul Eggert wrote:
> > It's documented that the builtin `unset' is non-portable, but what about
> > the use of unset variables vs. empty variables?  Is this distinction
> > always meaningful?
> 
> Yes.

let me add that the cache uses the distinction whether the variable is
set or not.   (test "${ac_cv_foo+set}" = set)

> > Also, I know that ${var:-default} is not portable.  Is
> > ${var-default}?
> 
> Yes.

And also
        test "${ac_cv_foo+set}" = set
which is used by the caching mechanism.

Have a nice day,
        Stepan