Perl Programming/Keywords/ref

The ref keyword

The ref function returns a non-empty string, if EXPRESSION is a reference and an empty string otherwise. Without EXPRESSION, $_ will be used. The returned value depends on the thing referenced to.

ref knows the following types:

Type	Notes
ARRAY	reference to an array
CODE
FORMAT
GLOB
HASH	reference to a hash
IO
LVALUE	reference to an lvalue that is not a variable
REF	reference to a reference
Regexp	regular expression resulting from qr//
SCALAR	reference to a scalar
VSTRING

If the referenced object has been blessed into a package, the name of that package is returned instead. This, however, is now considered "bad practice".

Syntax

  ref EXPRESSION
  ref