Something like this. If someone inserts a timer while we are doing
our checking we can always catch it on the next iteration of the loop.
--- Now runs unblocked
checkTimers :: IO ()
checkTimers =
do t <- readMVar timers -- takes it and puts it back
case M.size t of
-- no timers
0 -> threadDelay timeout
-- some timers
n -> do let (key@(time, name), io) = M.findMin t
now <- getClockTime
if (time <= now)
then do modifyMVar_ timers $ \a ->
return $! M.delete key a
try $ io -- don't think we care
return ()
else threadDelay timeout
checkTimers
On Dec 15, 2005, at 9:39 AM, Tomasz Zielonka wrote:
Perhaps you could use modifyMVar:
http://www.haskell.org/ghc/docs/latest/html/libraries/base/Control-
Concurrent-MVar.html#v%3AmodifyMVar
modifyMVar_ :: MVar a -> (a -> IO a) -> IO ()
A safe wrapper for modifying the contents of an MVar. Like withMVar,
modifyMVar will replace the original contents of the MVar if an
exception is raised during the operation.
--
http://wagerlabs.com/
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