I'm a beginner at haskell and ffi. I was trying to import and use is haskell
one C function, but I can't manage to do that.

Can someone show me an example how to create an import and a use example for
such a C function:
char functionName(char *, unsigned int, char *)

{-# LANGUAGE ForeignFunctionInterface #-}
module FOo where

import Foreign
import Foreign.C
import Data.Word

foreign import ccall "functionName" functionName_inC
        :: CString -> Word -> CString -> IO CChar

-- Assuming you really want to use Haskell Strings and Ints etc
-- and furthermore if the C function is really pure,
-- add the following wrapper.

functionName_h :: String -> Int -> String -> Char
functionName_h s0 i s1 =
    unsafePerformIO $
    withCString s0  $ \cs0->
    withCString s1  $ \cs1->
        do cchar <- functionName_inC cs0 (fromIntegral i) cs1
           return (castCCharToChar cchar)


FFI mailing list

Reply via email to