The FLI provides several different immediate types for the representation of floating point numbers. They consist of the following: :float , :lisp-double-float , :lisp-float, :lisp-short-float , and :lisp-single-float . The floating types all associate equivalent Lisp and C types, except the :lisp-float , which can take a modifier to cause an associations between different floating types. A :lisp-float associates a Lisp float with a C float by default, but a declaration of (:lisp-float :double) corresponds to a C double , for example.
Note: :lisp-short-float is available only on Unix.