typeid operator — Runtime type identification operator
postfix-expr := typeid ( expression ) | typeid ( type-id )
The typeid
operator returns a
const
reference to a type_info
object that describes type-id
or the type of expression
. If expression
is an lvalue (not a pointer) of
a polymorphic class, the type_info
of the most-derived class is returned. Otherwise, expression
is not evaluated, and the
type_info
of its static type is
returned.
Each distinct type has its own associated type_info
object, but type synonyms (such as
those created with typedef
) have
the same type_info
object.