My first guess would be missing -l parameter. The examples you have linked read: ghc --make compname.hs -lkernel32 Best regards, Krzysztof Skrzętnicki On Wed, May 29, 2013 at 9:13 AM, Kees Bleijenberg < k.bleijenberg@lijbrandt.nl> wrote:
I made a Delphi dll (32 bits windows). This dll exports a function named getPngVersion. This is a function with no arguments that returns a pointer to a array of chars.****
If I examine the dll with a tools like tdump, I can see the function getPngVersion on index 1.****
Now I want to use this dll in Haskell:****
** **
{-# LANGUAGE ForeignFunctionInterface #-}****
module Main(****
main****
)****
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where****
import Control.Monad****
import Foreign.C****
import Foreign.Marshal.Alloc****
import Foreign.Marshal.Array****
import System.Win32.Types****
** **
foreign import stdcall "glasPng getPngVersion" getPngDllVersion :: IO CString****
** **
main :: IO ()****
main = do ****
s <- getPngDllVersion****
putStrLn (show s)****
** **
Compiling this with ghc --make glasPng.hs gives:****
GlasPng.o: fake: (.text +0x82): undefined reference to ‘getPngVersion@0’ collect2 : Id returned 1 exit status ****
** **
I wonder what went wrong. In the foreign import line I use “glasPng…. “ to tell ghc, it has to searh in glasPng.dll (changing glasPng to glasPng.dll doesn’t help). I’ve changed the name of the function in the dll to getPngVersion@0 but no luck. I’ve read and tested the last example at http://stackoverflow.com/questions/1027246/haskell-foreign-import-stdcall-on... (win32_getComputername, this works!). I wonder how haskell knows which dll to use in this example?)****
Probably I’am doing something wrong with the way I tell ghc which dll to link or….****
** **
Any ideas?****
** **
Kees****
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