parconc-examples-0.1: ConcurrentUtils.hs

{-# LANGUAGE CPP, MagicHash, UnboxedTuples #-}

module ConcurrentUtils (
    -- * Variants of forkIO
    forkFinally
  ) where

import Control.Concurrent.STM
import Control.Exception
import Control.Concurrent
import Prelude hiding (catch)
import Control.Monad
import Control.Applicative

import GHC.Exts
import GHC.IO hiding (finally)
import GHC.Conc

#if __GLASGOW_HASKELL__ < 706
-- | fork a thread and call the supplied function when the thread is about
-- to terminate, with an exception or a returned value.  The function is
-- called with asynchronous exceptions masked.
forkFinally :: IO a -> (Either SomeException a -> IO ()) -> IO ThreadId
forkFinally action and_then =
  mask $ \restore ->
    forkIO $ try (restore action) >>= and_then
#endif