form - a form; evaluated.

results - the values resulting from the evaluation of form. These values must conform to the type supplied by value-type; see below.

It is permissible for form to yield a different number of values than are specified by value-type, provided that the values for which types are declared are indeed of those types. Missing values are treated as nil for the purposes of checking their types.

Regardless of number of values declared by value-type, the number of values returned by the the special form is the same as the number of values returned by form.

 (the symbol (car (list (gensym))))  #:G9876
 (the fixnum (+ 5 7))  12
 (the (values) (truncate 3.2 2))  1, 1.2
 (the integer (truncate 3.2 2))  1, 1.2
 (the (values integer) (truncate 3.2 2))  1, 1.2
 (the (values integer float) (truncate 3.2 2))    1, 1.2
 (the (values integer float symbol) (truncate 3.2 2))  1, 1.2
 (the (values integer float symbol t null list) 
      (truncate 3.2 2))  1, 1.2
 (let ((i 100))
    (declare (fixnum i))
    (the fixnum (1+ i)))  101
 (let* ((x (list 'a 'b 'c))
        (y 5))
    (setf (the fixnum (car x)) y)
    x)  (5 B C)

 (the (values integer integer) (floor x y))
 (the (values string t)
      (gethash the-key the-string-table))

setf can be used with the type declarations. In this case the declaration is transferred to the form that specifies the new value. The resulting setf form is then analyzed.