Please, can you help me with following: I have an external dll that I'm importing in my haskell program. In some particular cases the dll crashes. Simplified: first I need to send to dll with MethodA some parameters and then call MethodB to do some calculations on those parameters. If I didn't give enough parameters then MethodB will crash the whole dll and my Haskell application. Is there a way to handle this? Unfortunately there are no exceptions thrown from the dll. In ghci I'm getting following message: ERROR in InitNumericalSystem::initializeSystem. JuncLabel. I have tried to use "catchAny but that didn't help. c_run is my external dll method which takes 4 input parameters: catchAny :: IO a -> (SomeException -> IO a) -> IO a catchAny = Control.Exception.catch main :: IO () main = do let timeTot = []::[CDouble] timeNow = []::[CDouble] runType = 2::CInt timeTotPtr <- newArray timeTot timeNowPtr <- newArray timeNow result <- (catchAny $ c_run timeTotPtr runType timeNowPtr 0) $ \e -> do putStrLn $ "Got an exception: " ++ show e putStrLn "Returning dummy value of -1" return (-1) free timeTotPtr free timeNowPtr print result I have tried also with withAsync, and no luck tryAny :: IO a -> IO (Either SomeException a) tryAny action = withAsync action waitCatch catchAny :: IO a -> (SomeException -> IO a) -> IO a catchAny action onE = tryAny action >>= either onE return try2 :: IO () try2 = do let timeTot = []::[CDouble] timeNow = []::[CDouble] runType = 2::CInt timeTotPtr <- newArray timeTot timeNowPtr <- newArray timeNow putStrLn $ "c_run going to call c_run.." result <- catchAny (c_run timeTotPtr runType timeNowPtr 0) (const $ return (-1)) free timeTotPtr free timeNowPtr putStrLn $ "Result: " ++ show result Is there a way how I can handle this? cheers, m.