Size of an Hash reference

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

Hi Monks,

i have basic doubt regarding the hash references,

basically i wanted to check the emptyness of the hash

reference in my code,when there are key-value pairs i get

the correct count, but when there are no key-values

pairs, still my hash reference shows the below output

$VAR1 = \{
            '' => undef
          };
[download]

why this undef value existing in hash reference, and

size of the hash reference returns as 1" how do i check the emptyness here.

any idea please...!