9 Apr
2010
9 Apr
'10
4:40 a.m.
Simon Marlow wrote:
but they are needlessly complicated, in my opinion. This offers the same functionality:
mask :: ((IO a -> IO a) -> IO b) -> IO b mask io = do b <- blocked if b then io id else block $ io unblock
How does forkIO fit into the picture? That's one point where reasonable code may want to unblock all exceptions unconditionally - for example to allow the thread to be killed later. timeout t io = block $ do result <- newEmptyMVar tid <- forkIO $ unblock (io >>= putMVar result) threadDelay t `onException` killThread tid killThread tid tryTakeMVar result regards, Bertram