class-of
(class-of object)
Returns the class METAOBJECT of any value -- the same memoized standard-class instance find-class answers, so (eq (class-of x) (find-class 'name)) holds. A CLOS instance answers its class, a defstruct instance its structure type (as a standard-class instance too -- there is no structure-class), and every other value a slot-less built-in class named integer, string, cons, ..., with t for values outside that set (arrays included). Read the name with class-name.