Useless use of a constant (ict) in void context

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

I have the following code running on Strawberry perl 32 bit 5.14.2 and it gives the error shown in the titel. It is down to the use open line but I don't understand why.

use open ':std', ':encoding(utf8)';
use Test::More;

my $has_test_nowarnings = 1;
eval "require Test::NoWarnings";
$has_test_nowarnings = undef if $@;

done_testing();
[download]

The full error is Useless use of a constant (ict) in void context at I:/strawberry-perl-5.14.2.1-3 2bit-portable/perl/vendor/lib/Test/NoWarnings.pm line 3. I don't get that error with 64 bit strawberry perl. The line 3 referred to is "use strict;".

Comment on Useless use of a constant (ict) in void context Download Code

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Re: Useless use of a constant (ict) in void context by ikegami (Patriarch) on Nov 15, 2013 at 18:51 UTC
Convert the line endings of `Test/NoWarnings.pm` from LF to CRLF. Perl tries to seek back (for reasons I can't remember, perhaps BOM detection), but gets the position wrong because the line ending are different than expected. As a result, Perl ends up thinking the file being executed contains `ict; use warnings; use Carp (); ...` [download] or, after your edit, `rnings; use Carp (); ...` [download] .	[reply] [d/l] [select]
Re: Useless use of a constant (ict) in void context by tobyink (Canon) on Nov 15, 2013 at 13:58 UTC
There's possibly something wrong with your copy of Test::NoWarnings - try reinstalling from CPAN. Even better, try Test::Warnings which is a nicer module. `use Moops; class Cow :rw { has name => (default => 'Ermintrude') }; say Cow->new->name`	[reply]
Re: Useless use of a constant (ict) in void context by LanX (Saint) on Nov 15, 2013 at 13:27 UTC
Ehm ... the code you've posted doesn't show any `use strict` so I can only speculate that something may be malformed in the "strict" part. Unicode sideeffects ? Cheers Rolf ( addicted to the Perl Programming Language)	[reply] [d/l]
Re^2: Useless use of a constant (ict) in void context by hdb (Monsignor) on Nov 15, 2013 at 13:29 UTC
Line 3 in .../Test/NoWarnings.pm ?	[reply]
Re^2: Useless use of a constant (ict) in void context by mje (Curate) on Nov 15, 2013 at 13:50 UTC
As I said (and the error says) the suspect line is line 3 in Test::NoWarnings and it does contain use strict. I've pasted it below: `package Test::NoWarnings; use 5.006; use strict; use warnings;` [download]	[reply] [d/l]
Re^3: Useless use of a constant (ict) in void context by hdb (Monsignor) on Nov 15, 2013 at 13:52 UTC
Interestingly, line 3 is `use 5.006;`.	[reply] [d/l]
Re^4: Useless use of a constant (ict) in void context by mje (Curate) on Nov 15, 2013 at 13:56 UTC
Re^4: Useless use of a constant (ict) in void context by taint (Chaplain) on Nov 15, 2013 at 14:02 UTC
Re^5: Useless use of a constant (ict) in void context by mje (Curate) on Nov 15, 2013 at 14:07 UTC
Some notes below your chosen depth have not been shown here
Re: Useless use of a constant (ict) in void context (perl -V) by Anonymous Monk on Nov 15, 2013 at 23:22 UTC
Can you post the output of `perl -V`?	[reply] [d/l]