Re: Find out, if "use warnings(all)" and "use strict(all)" are used

[Krambambuli]

It's important I believe to cut a very clear line between what happens at compile time and what happens at runtime. Once those very distinctive steps are put apart and understood, it might be that your question changes.

Playing a bit with BEGIN{} might help in getting things apart;

use strict;

my $all;
use warnings 'all';
BEGIN {   $all = unpack( 'b*', ${^WARNING_BITS} ); }
print "ALL : $all\n";

my $none;
no warnings 'all';
BEGIN {   $none = unpack( 'b*', ${^WARNING_BITS} ); }
print "NONE: $none\n";

my $void;
use warnings 'void';
BEGIN {   $void = unpack( 'b*', ${^WARNING_BITS} ); }
print "VOID: $void\n";

This will display at runtime the values in use at compile time _at that specific point in the program_.

Note that to unpack ${^WARNING_BITS} - a 96 bits value - your bintodec sub won't work.

You might be interested in having a look on the warnings.pm source code - it's not really scary and definitely worth a look - and maybe check the 'Pragmatic modules' in perlmodlib.

Hope that helps.

[Tobiwan]

Thanks, that was a good hint. I tried to read the warning and strict bits from other packages, so I've to find a way to do it without explicit BEGIN blocks. The following thing works, but why ?!?

package Aa;
use warnings;
#no warnings 'void'; 
use strict;
#no strict 'refs';

package Bb;
#>> when you uncomment this, it wont work!!
#use strict;
#use warnings;
#<<
    
my $strict = eval('package Aa;my $h;BEGIN { $h = ${^H} };return $h;');
printf "use strict " . ($strict == 1794 ? 'yes' : 'no') . "\n";
my $warn = eval('package Aa;my $w;BEGIN { $w = ${^WARNING_BITS} };retu
+rn $w;');
printf "use warnings " . (unpack('b*', warnings::bits('all')) == unpac
+k('b*', $warn) ? 'yes' : 'no') . "\n";

This prints:

use strict = yes
use warnings = yes

till you use all-warnings ans all-stricts. Conclusion: it works fine and do what I want.

And by the way: in last few weeks I've see a lot of little perl wonders like this. I think, there must be a perl-good. Now I'm a believer :D