Concurrent and Posix libraries...

[Marcus Shawcroft]

Hi,

I want to use a thread in concurrent haskell to manage a posix
fork/exec/wait. I expected the test code attached below to output
"recovering result" once, instead I get "recovering result" twice. Can
anyone shed some light on whats going wrong?

(ghci 5.02.1 x86 linux)

Thanks
/Marcus

> module Test where

> import Concurrent
> import Posix

> main = do
>   mv <- newEmptyMVar
>   forkIO $ do x <- forkProcess
>     case x of
>       Nothing -> do
>         executeFile "sleep" True ["2"] Nothing
>         error "oops"
>       Just pid ->
>         getProcessStatus True False pid
>         putMVar mv ()
>   print "recovering result"
>   takeMVar mv