defctype macro provides a mechanism similar to C's
typedef to define new types. The new type inherits
base-type's translators, if any. There is no way to define
translations for types defined with
defctype. For that,
you should use define-foreign-type.
(defctype my-string :string "My own string type.") (defctype long-bools (:boolean :long) "Booleans that map to C longs.")