in reply to Re^8: Use of uninitialized value in substr
in thread Use of uninitialized value in substr

I do not believe for one second that you think that `foo` is in anyway equivalent to "explicit undef".

Both are means of producing the same value.

Nor do I believe that you--uniquely amongst the responders in this thread--cannot interpret the explicit use of undef in the OP

Nor should you. What wasn't clear is that you wanted to you only wanted to disable the warning when the undef function was used. In your mind, undef is some magical value. In mine, it's a function like any other.

I don't know why you say I'm unique. moritz said said exactly what I did.

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Re^10: Use of uninitialized value in substr
by BrowserUk (Patriarch) on May 03, 2010 at 19:20 UTC
    In your mind, undef is some magical value. In mine, it's a function like any other.

    Then my mind is right, and yours is wrong! 

    #! perl -slw
use 5.010;
use strict;
use Inline C => Config => BUILD_NOISY => 1;
use Inline C => <<'END_C',  NAME => 'uCmp', CLEAN_AFTER_BUILD => 0;

bool uCmp( SV* t ) {
    return (bool)( t == (&PL_sv_undef) );
}

END_C

print 'explicit undef: ', uCmp( undef ) ? 1 : 0;

my $s;
print 'uninitalised lexical: ', uCmp( $s ) ? 1 : 0;

my @a;
print 'uninitalised array element: ', uCmp( $a[ 5 ] ) ? 1 : 0;

my %h;
print 'uninitalised hash value: ', uCmp( $h{fred} ) ? 1 : 0;

our $g;
print 'uninitalised global: ', uCmp( $g ) ? 1 : 0;


print 'Other unexplicit undef values: ', uCmp( `unknown_command` ) ? 1
+ : 0;

__END__
C:\test>uCmp
explicit undef: 1
uninitalised lexical: 0
uninitalised array element: 0
uninitalised hash value: 0
uninitalised global: 0
'unknown_command' is not recognized as an internal or external command
+,
operable program or batch file.
Usage: main::uCmp(t) at C:\test\uCmp.pl line 28.

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    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
[d/l]
      I'm aware of PL_sv_undef and how it's used. It's besides the point. In Perl land, undef is undef is undef. There's only one case where I know where that doesn't hold (in open), and I believe that was a mistake (or a backwards compatibility solution).
[reply]
[d/l]
        I'm aware of PL_sv_undef and how it's used.e

        Really? Then I'm surprised it took you this long to get with the program and discuss the actual idea, rather than blundering around in willful misinterpretation land.

        In Perl land, undef is undef is undef.... and I believe that was a mistake

        And you speak for all "Perl land" do you?

        And I believe differently. So you'll excuse me if I pay little mind to your "I don't know why you're asking this question".

        Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
        "Science is about questioning the status quo. Questioning authority".
        In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]

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