+-- wint_t, wctrans_t, wctype_t
+
+{- $ctypes
+
+These types are needed to accurately represent C function prototypes,
+in order to access C library interfaces in Haskell. The Haskell system
+is not required to represent those types exactly as C does, but the
+following guarantees are provided concerning a Haskell type @CT@
+representing a C type @t@:
+
+* If a C function prototype has @t@ as an argument or result type, the
+ use of @CT@ in the corresponding position in a foreign declaration
+ permits the Haskell program to access the full range of values encoded
+ by the C type; and conversely, any Haskell value for @CT@ has a valid
+ representation in C.
+
+* @'sizeOf' ('Prelude.undefined' :: CT)@ will yield the same value as
+ @sizeof (t)@ in C.
+
+* @'alignment' ('Prelude.undefined' :: CT)@ matches the alignment
+ constraint enforced by the C implementation for @t@.
+
+* The members 'peek' and 'poke' of the 'Storable' class map all values
+ of @CT@ to the corresponding value of @t@ and vice versa.
+
+* When an instance of 'Prelude.Bounded' is defined for @CT@, the values
+ of 'Prelude.minBound' and 'Prelude.maxBound' coincide with @t_MIN@
+ and @t_MAX@ in C.
+
+* When an instance of 'Prelude.Eq' or 'Prelude.Ord' is defined for @CT@,
+ the predicates defined by the type class implement the same relation
+ as the corresponding predicate in C on @t@.
+
+* When an instance of 'Prelude.Num', 'Prelude.Read', 'Prelude.Integral',
+ 'Prelude.Fractional', 'Prelude.Floating', 'Prelude.RealFrac', or
+ 'Prelude.RealFloat' is defined for @CT@, the arithmetic operations
+ defined by the type class implement the same function as the
+ corresponding arithmetic operations (if available) in C on @t@.
+
+* When an instance of 'Bits' is defined for @CT@, the bitwise operation
+ defined by the type class implement the same function as the
+ corresponding bitwise operation in C on @t@.
+
+-}