- data Storable a => GlobalVariable a
- writeGlobalVariable :: Storable a => GlobalVariable a -> a -> IO ()
- readGlobalVariable :: Storable a => GlobalVariable a -> IO a
- class Storable cb => Callback cb where
When libraries provide types for functions those
types are made instances of class
class is used to exchange between Haskell functions
and a representation (i.e., a hidden pointer) that
can be used or is provided by foreign code.
nullCallback can be used like
makeCallback takes a Haskell function and
gives a representation of it in the form of the
type expected by foreign code.