Dean, Thanks very much, that indeed worked. -- Peter On Wed, Nov 3, 2010 at 9:16 PM, Dean Herington wrote:

At 8:45 PM -0700 11/3/10, Peter Schmitz wrote:

...

I have a program (test.hs):

...

 module Main (main) where  import System.Exit  main :: IO ExitCode  main = do    return (ExitFailure 1)

In another program, I invoke it via 'system':

...

   exitCode <- system ".\\test.exe"    case (exitCode) of       ExitFailure failCnt -> do          putStrLn $ "-- Fail count is: " ++ show failCnt          exitFailure       ExitSuccess -> do          putStrLn $ "-- OK."          exitSuccess

but it always gets ExitSuccess (not ExitFailure failCnt as I expected). (I am running under Windows.)

My other use of system (such as with ghc commands) works okay, sometimes getting success, sometimes failure, as expected.

Any suggestions much appreciated. Thanks, -- Peter

The value returned by `main` is always discarded.  You need to use `exitWith`:

main = exitWith (ExitFailure 1)