Hum... I have tried all of those approaches and none of them work.

For example, the following script:

---- Start script

use strict;

my %hash = {};

print "\%hash=".%hash."\n";
print "scalar(\%hash)=".scalar(%hash)."\n";
print "length(\%hash)=".length(%hash)."\n";
%hash = undef;
print "defined(\%hash)=".defined(%hash)."\n";
[download]

--- End script

Results in the following output:

%hash=1/8
scalar(%hash)=1/8
length(%hash)=3
defined(%hash)=1
[download]

Does any of you know what the problem is? I am using perl v5.8.3.

Originally posted as a Categorized Answer.