[Haskell-cafe] Concurrency question

[Dmitry V'yal]

Donald Bruce Stewart wrote:

> Can I ask if just using a `seq` works as well? That was enough (now I
> recall) for the watchdog code I posted earlier.
> 
> -- Don

In my case this doesn't work

 >timeout :: DeepSeq a => Int -> IO a -> IO (Maybe a)
 >timeout n t = do res <- par_io timer thr  --timer
 >                 return res
 >    where thr = do res <- t
 >                   return $! Just res
 >          timer = do threadDelay $ n * 1000
 >                     return Nothing

It's probably because "resolve" function has type
 > resolve :: CNF -> (Bool, [(Int,Int)])
So it should be sequenced deeper.