http://www.perlmonks.org?node_id=1151109


in reply to Re^2: defined defined -- Bug or "Feature"?
in thread defined defined -- Bug or "Feature"?

The docs say that it returns a boolean value, i.e. a true or false value. It would be surprising for a false value to also be undefined, as you would get 'undefined' warnings if you tried using operators on the results. This shouldn't warn:
$x = defined($y) ^ defined($z);

Dave.