Mailing List Archive: local $^O = $^O --> undef

local $^O = $^O --> undef

Oct 26, 2023, 3:29 PM

Post #1 of 3 (132 views)

perl -wE 'local $^O = $^O; die "oops" unless defined $^O; say "IT IS
$^O";'

dies because the localized $^O is undef. Doing local $^O = $^O."";
avoids the problem

(Why would anyone do that ?!? In a module test I was localizing $^O to
lie about the OS to exercise some OS-specific behavior, using a loop;
one case was to use the actual OS of the cpan smoker, i.e. the original
$^O.)

FWIW, local $PID = $PID; works (doesn't have this problem), but local
$^F = $^F; becomes 0. I haven't tried others.

-Jim

Re: local $^O = $^O --> undef [ In reply to ]

lukasmai.403+p5p at gmail

Oct 26, 2023, 8:34 PM

Post #2 of 3 (132 views)

Permalink

On 27.10.23 00:29, Jim Avera wrote:
> perl -wE 'local $^O = $^O; die "oops" unless defined $^O; say "IT IS
> $^O";'
>
> dies because the localized $^O is undef. Doing local $^O = $^O."";
> avoids the problem

See also https://github.com/Perl/perl5/issues/5835.

Re: local $^O = $^O --> undef [ In reply to ]

jim.avera at gmail

Oct 26, 2023, 10:01 PM

Post #3 of 3 (132 views)

Permalink

On 10/26/23 3:29 PM, Jim Avera wrote:
> perl -wE 'local $^O = $^O; die "oops" unless defined $^O; say "IT IS
> $^O";'
>
> dies because the localized $^O is undef. Doing local $^O =
> $^O.""; avoids the problem
>
> (Why would anyone do that ?!? In a module test I was localizing $^O
> to lie about the OS to exercise some OS-specific behavior, using a
> loop; one case was to use the actual OS of the cpan smoker, i.e. the
> original $^O.)
>
> FWIW, local $PID = $PID; works (doesn't have this problem), but local
> $^F = $^F; becomes 0. I haven't tried others.
>
> -Jim
>
Yes, this looks like a dup of #5835
<https://github.com/Perl/perl5/issues/5835> as mauke pointed out!