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

use strict;                                                           
+          
use warnings;

sub c {
    no warnings;
    print $d; 
}
sub a{
    no warnings;
    print $b; 
    c;  
}
a();

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The first Use of uninitialized value can be fixed by no warnings, but the second is reporting a fatal error,why?

Replies are listed 'Best First'.
Re: How exactly does no work?
by moritz (Cardinal) on Feb 16, 2012 at 11:24 UTC

    Warnings are not errors, and errors are not warnings.

    The fatal error comes from strict because you didn't declare $d. And because it comes from strict and not warnings, no warnings; has no effect on it. While you can say no strict 'vars';, it's much better to just declare $d with my.

    Perl 6 - second systems done right
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      Why is it NOT fatal when I print $b; in sub a?
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      Is no a run time or compile time thing?

      And it seems it's only effective in the current block, not in outer or inner block

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        Minimal reference to the docs -- say perldoc -f no -- would put you on the path to answers. See also, as the docs suggest, use.
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