c2hs is an interface generator that simplifies the development of
Haskell bindings to C libraries.  The tool processes existing C
header files that determine data layout and function signatures on
the C side, in conjunction with Haskell modules that specify
Haskell-side type signatures and marshaling details. Hooks embedded
in the Haskell code signal access to C structures and functions;
they are expanded by the interfacing tool in conjunction with
information in the corresponding C header file.  A noteworthy
property is the lightweight nature of the approach.