{-# LANGUAGE ScopedTypeVariables #-}
module Main(main) where

import System.Win32.DLL
import System.Win32.Types as Win32Types
import Foreign.Ptr
import Foreign.C.String
import Foreign.ForeignPtr

foreign import ccall "dynamic"
  --c_TestInt :: FunPtr (Int -> IO (Int)) -> Int -> IO (Int)
  c_funcRetString :: FunPtr (IO (CString)) -> IO (CString)
foreign import ccall "dynamic"
  c_funcInstantiate :: FunPtr (CString -> CString -> HMODULE -> IO (Ptr ())) ->  CString -> CString -> HMODULE -> IO (Ptr ())

dllNames = ["tank"]

invokeFunction dll funcName funcType convType = do
  func <- getProcAddress dll funcName
  ret <- funcType $ castPtrToFunPtr func
  convType ret

main :: IO ()

main = do
  dll <- loadLibrary $ head dllNames
  invokeFunction dll "x1" c_funcRetString peekCString >>= putStrLn . show
  invokeFunction dll "x2" c_funcRetString peekCString >>= putStrLn . show
  instantiateFunc <- getProcAddress dll "x3"
  instantiateRet <- c_funcInstantiate (castPtrToFunPtr instantiateFunc) (newCString "t1") (newCString "t2") dll
  putStrLn . show $ 1


C:\source\speciale\r_and_d\source\hs_prototype\dynamic_loading_tank_tankcontroller\main.hs:30:74-88: Couldn't match type `IO CString' with `Ptr Foreign.C.Types.CChar' …
    Expected type: CString
      Actual type: IO CString
    In the second argument of `c_funcInstantiate', namely
      `(newCString "t1")'
    In a stmt of a 'do' block:
      instantiateRet <- c_funcInstantiate
                          (castPtrToFunPtr instantiateFunc)
                          (newCString "t1")
                          (newCString "t2")
                          dll
C:\source\speciale\r_and_d\source\hs_prototype\dynamic_loading_tank_tankcontroller\main.hs:30:92-106: Couldn't match type `IO CString' with `Ptr Foreign.C.Types.CChar' …
    Expected type: CString
      Actual type: IO CString
    In the third argument of `c_funcInstantiate', namely
      `(newCString "t2")'
    In a stmt of a 'do' block:
      instantiateRet <- c_funcInstantiate
                          (castPtrToFunPtr instantiateFunc)
                          (newCString "t1")
                          (newCString "t2")
                          dll
Compilation failed.