To determine if any reference is blessed or not, I would highly recommend Ref::Util's is_blessed_ref() subroutine. That is precisely what it is designed for.

I strongly suspect that determining the blessedness of a given reference is not what SergioQ was actually enquiring about, however.

Update: sample test set to show it in action. You can throw anything at it and it won't complain - just return true if the arg is a blessed ref and false otherwise.

use strict;
use warnings;

use Ref::Util 'is_blessed_ref';
use Test::More tests => 9;

ok ! is_blessed_ref (undef), 'No: undef';
ok ! is_blessed_ref (0),     'No: false';
ok ! is_blessed_ref (1),     'No: true';

my ($x, @x, %x);

ok ! is_blessed_ref (\$x), 'No: scalar ref';
ok ! is_blessed_ref (\@x), 'No: array ref';
ok ! is_blessed_ref (\%x), 'No: hash ref';

bless \$x, 'Foo';
bless \@x, 'Foo';
bless \%x, 'Foo';

ok is_blessed_ref (\$x), 'Yes: blessed scalar ref';
ok is_blessed_ref (\@x), 'Yes: blessed array ref';
ok is_blessed_ref (\%x), 'Yes: blessed hash ref';
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