+{- $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' ('undefined' :: CT)@ will yield the same value as
+ @sizeof (t)@ in C.
+
+* @'alignment' ('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 'Bounded' is defined for @CT@, the values of
+ 'minBound' and 'maxBound' coincide with @t_MIN@ and @t_MAX@ in C.
+
+* When an instance of 'Eq' or '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 'Num', 'Read', 'Integral', 'Fractional', 'Floating',
+ 'RealFrac', or '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@.
+
+-}
+