How to determine if 'strict' is enabled

kcott has asked for the wisdom of the Perl Monks concerning the following question:

Background

I'm doing some testing of Perl::Dist::APPerl on various platforms. I have a test script which currently checks that 'use v5.36;' enables the warnings pragma and features are enabled or disabled as appropriate.

Question

I'm looking for a platform-independent way to determine if the strict pragma is in effect without forcing an abort.

If strict is specifically used, it can be determined from %INC:

ken@titan ~/tmp
$ perl -e 'use strict; print "$_\n" for keys %INC;'
strict.pm

ken@titan ~/tmp
$ perl -e 'use strict; my $x = xyz;'
Bareword "xyz" not allowed while "strict subs" in use at -e line 1.
Execution of -e aborted due to compilation errors.
[download]

However, if strict is enabled automatically via use VERSION (where VERSION >= 5.12), this method doesn't work:

ken@titan ~/tmp
$ perl -e 'use 5.012; print "$_\n" for keys %INC;'

ken@titan ~/tmp
$ perl -e 'use 5.012; my $x = xyz;'
Bareword "xyz" not allowed while "strict subs" in use at -e line 1.
Execution of -e aborted due to compilation errors.
[download]

Any help with this would be appreciated. Thankyou.

— Ken

Comment on How to determine if 'strict' is enabled Select or Download Code

Replies are listed 'Best First'.
Re: How to determine if 'strict' is enabled by ikegami (Patriarch) on Jun 07, 2023 at 03:58 UTC
You can't use `%INC`. `$ perl -le'no strict; print $INC{ "strict.pm" } ?1:0' 1 # False positive $ perl -le'{ use strict; } print $INC{ "strict.pm" } ?1:0' 1 # False positive $ perl -le'use JSON; print $INC{ "strict.pm" } ?1:0' 1 # False positive $ perl -le'use v5.20; print $INC{ "strict.pm" } ?1:0' 0 # False negative` [download] You can use `( caller(0) )[8]` in a sub. `$ perl -le' sub f { ( ( caller(0) )[8] & 0x602 ) == 0x602 } print f ?1:0; ' 0 $ perl -le' sub f { ( ( caller(0) )[8] & 0x602 ) == 0x602 } use strict; print f ?1:0; ' 1 $ perl -le' sub f { ( ( caller(0) )[8] & 0x602 ) == 0x602 } use v5.20; print f ?1:0; ' 1` [download] 0x2 is strict refs, 0x200 is strict subs, and 0x400 is strict vars.	[reply] [d/l] [select]
Re^2: How to determine if 'strict' is enabled by stevieb (Canon) on Jun 07, 2023 at 05:16 UTC
This enlightened me. Is this documented anywhere ikegami? If so, it's something I've completely overlooked, glossed over or for some reason over the years completely ignored.	[reply]
Re^3: How to determine if 'strict' is enabled by kcott (Archbishop) on Jun 07, 2023 at 06:15 UTC
G'day stevieb, "Is this documented anywhere ikegami?" I looked this up after ++ikegami's response. See caller for element-8, `$hints`, and subsequent discussion. See "strict's source code" for the numbers (`0x2`, `0x200`, and `0x400`). — Ken	[reply] [d/l] [select]
Re^4: How to determine if 'strict' is enabled by LanX (Saint) on Jun 07, 2023 at 11:27 UTC
Re^2: How to determine if 'strict' is enabled by kcott (Archbishop) on Jun 07, 2023 at 04:31 UTC
G'day ikegami, ++ Thanks. That's just the sort of thing I was looking for. — Ken	[reply]
Re: How to determine if 'strict' is enabled by tobyink (Canon) on Jun 12, 2023 at 09:34 UTC
`my $strict_enabled = do { my $code = sprintf( '$____DUMMY____%d = 1', 1_000_000 + int( rand 8_ +999_888 ) ); not eval( $code ); }; if ( $strict_enabled ) { print "strict vars\n"; } else { print "no strict vars\n"; }` [download] Hire me at Toby Ink Ltd or Join my OnlyFans	[reply] [d/l]


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