Re: [Haskell-beginners] STM and IO

On Thu, 9 Apr 2009 12:03:03 +0200 Quentin Moser wrote:

Here's an example inspired by the documentation of Control.Concurrent:

...

import Control.Concurrent import Control.Exception (finally)

myFork :: IO () -> IO (MVar ()) myFork a = do v <- newEmptyMVar a `finally` (putMVar v ())

myWait :: MVar () -> IO () myWait = readMVar

Oops, my code is completely messed up. Here's a correct version:

myFork a = do v <- newEmptyMVar forkIO $ a `finally` putMVar v () return v

myWait = readMVar >> return ()