Perl 5 version 14.3 documentation
Returns a non-empty string if EXPR is a reference, the empty string otherwise. If EXPR is not specified,
$_will be used. The value returned depends on the type of thing the reference is a reference to. Builtin types include:
If the referenced object has been blessed into a package, then that package name is returned instead. You can think of
The return value
LVALUEindicates a reference to an lvalue that is not a variable. You get this from taking the reference of function calls like
VSTRINGis returned if the reference points to a version string.
Regexpindicates that the argument is a regular expression resulting from
See also perlref.