Re^2: Unexpected warning

> You get that warning on that line if $something is undefined.

yep I can reproduce this. =)

Seems like in the context of the call warnings were disabled.

  DB<132> use warnings; sub tst {my $a=shift, my $b =shift}

  DB<133> %h=()

  DB<134> $bla=""
 => ""

  DB<135> tst $h{$bla}
 => (undef, undef)

  DB<136> undef $bla
 => undef

  DB<137> tst $h{$bla}
Use of uninitialized value in scalar assignment at (eval 81)[multi_per
+l5db.pl:644] line 2.
[download]

Cheers Rolf

( addicted to the Perl Programming Language)

Comment on Re^2: Unexpected warning Download Code

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Re^3: Unexpected warning by salva (Canon) on Nov 18, 2013 at 15:08 UTC
I can reproduce it myself too now: `tst(undef); # doesn't warn from tst tst($foo{undef}); # doesn't warn from tst tst($foo{$undef}); # warns from tst` [download] I would say this is a bug in perl, or I am missing something?	[reply] [d/l]
Re^4: Unexpected warning by samwyse (Scribe) on Nov 18, 2013 at 16:14 UTC
The undef value is subtly different from using an undefined variable, so that may be causing the problem. `tst($foo{undef}); # doesn't warn from tst` This uses the undef value as a key into the %foo hash; the key presumably doesn't exist so Perl returns undef. This is working as I would expect. `tst($foo{$undef}); # warns from tst` This looks up the value of $undef, which presumably isn't defined, so Perl should flag an error at that statement, not inside tst. If that is the case, then it, too, is working as I would expect.	[reply] [d/l] [select]
Re^3: Unexpected warning by hdb (Monsignor) on Nov 18, 2013 at 15:07 UTC
I get no warnings from the code below: `use strict; use warnings; sub test { my $x = shift; } my %hash = ( a => "a" ); test $hash{"b"};` [download]	[reply] [d/l]
Re^4: Unexpected warning by LanX (Saint) on Nov 18, 2013 at 15:15 UTC
The key must be undef. `lanx@nc10-ubuntu:~$ perl use strict; { use warnings; sub test { my $x = shift; } } my %hash = ( a => "a" ); my $key; test $hash{$key} Use of uninitialized value in scalar assignment at - line 3. lanx@nc10-ubuntu:~$ perl -version This is perl, v5.10.0 built for i486-linux-gnu-thread-multi` [download] I agree with salva that this is kind of a bug in lexical warnings. Cheers Rolf ( addicted to the Perl Programming Language)	[reply] [d/l]