http://www.perlmonks.org?node_id=1072259


in reply to Re: Dualvars besides $!
in thread Dualvars besides $!

A value for "true" is also dualvar:

perl -MScalar::Util -E 'say Scalar::Util::isdual(!0)'

...outputs '1', indicating the test was true.


Dave

In Section Seekers of Perl Wisdom