I've tried a little searching, but I get a lot of false hits.

I like to "use strict" and "#! /usr/bin/perl -w". I found today that not all uses of uninitialized values trigger the "Use of uninitialized value" warning:

my $x = undef;
my $y = undef;
if ($y) { ... }
if (! $y) { ... }
if ($y && ! $y) { ... }
if (exists $x->{notdef}) { ... }
if (defined $x->{notdef}) { ... }
if ($x->{notdef}) { ... }
    # and none of those autovivify it.

[download]

(at least under Perl 5.008008, which is what my workplace uses).

Is there a more complete listing of conditions that cause the warning and/or those that do not? From the above, apparently it doesn't happen with

In reply to When DOESN'T "Use of uninitialized value" show up? by Tim McDaniel

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