sub refaddr($) {    

     # prototypes are usually suspect, here a prototype
     # is reasonable because the usage of this routine is
     # very predictable.

  # Save the class; fail if we don't have an object

  my $pkg = ref($_[0]) or return undef;
  
  # rebless the object into a package that is supposed to
  # NOT to overload numeric coercion.  This code is more
  # robust than yours but still fails if UNIVERSAL overloads
  # '0+'; to really be safe we'd need to
  # use CORE:: functions explicitly.
  #
  # I would have probably just used 'Scalar::Util' but
  # I'm the sort who goes looking for 'Scalar::Util::Fake',
  # you have to use something like "S::U::No_SuCh_PkG"
  # before I believe you mean it.

  bless $_[0], 'Scalar::Util::Fake';
  
  # int() seems to have acquired a little magic when
  #  applied to a reference.  I hadn't noticed.

  my $i = int($_[0]);

  # restore the object to its package

  bless $_[0], $pkg;
 
  # return the decimal address  

  $i;
}