Mailing List Archive: warnings::warn using only standard warnings categories?

warnings::warn using only standard warnings categories?

jim.avera at gmail

Aug 16, 2023, 11:54 AM

Post #1 of 2 (40 views)

Can /warnings::warn/ be used with only standard warnings categories
(not a module-custom cat)?

warnings::warn() dies unless warnings::register() was previously called,
but if the package does not wish to create any new warnings categories
then warnings::register should not be used, I assume.

|#!/usr/bin/env perl||
||
||package Foo;||
||sub import {||
|| use Carp;||
|| use warnings;||
|| my $enabled = warnings::enabled("deprecated");||
||
|| warnings::warn "This is deprecated" if $enabled; #dies with "package
'Foo' not registered for warnings"||||
||}||
||
||package main;||
||
||use warnings FATAL => 'all';||
||Foo->import("blah");||
||die "SHOULD NOT GET HERE (due to FATAL => all)";||
|

Re: warnings::warn using only standard warnings categories? [ In reply to ]

perl5-porters at perl

Aug 18, 2023, 10:34 AM

Post #2 of 2 (38 views)

Jim Avera wrote:
>
> Can warnings::warn be used with only standard warnings categories (not a module-custom cat)?

Yes. <https://perldoc.perl.org/warnings> shows several examples, such as:

warnings::warn("deprecated", "open is deprecated, use new instead");

> use warnings FATAL => 'all';
> Foo->import("blah");
> die "SHOULD NOT GET HERE (due to FATAL => all)";

Fatal warnings are documented to be buggy and unreliable. Instead of stopping at the supposedly fatal warning, the following says BAR on all versions of perl I have installed, all the way down to 5.10.1:

perl -E 'use warnings FATAL => "all"; warn "foo"; say "BAR";'

--
Arne Johannessen
<https://arne.johannessen.de/>