What do Perl functions that return Boolean actually return

Question

The Perl defined function (and many others) returns \"a Boolean value\".

Given Perl doesn\'t actually have a Boolean type (and uses values like 1 for t

Answer 1

They return a special false value that is "" in string context but 0 in numeric context (without a non-numeric warning). The true value isn't so special, since it's 1 in either context. defined() does not return undef.

(You can create similar values yourself with e.g. Scalar::Util::dualvar(0,"").)