Perl 5 version 20.3 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:
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
If the referenced object has been blessed into a package, then that package name is returned instead. But don't use that, as it's now considered "bad practice". For one reason, an object could be using a class called
IO, or even
refdoesn't take into account subclasses, like
blessed(in the Scalar::Util module) for boolean checks,
isafor specific class checks and
reftype(also from Scalar::Util) for type checks. (See perlobj for details and a
See also perlref.