caf-0.0.2: Examples/Example07.hs

module Control.Concurrent.Futures.Example07 where
import qualified Control.Concurrent.Futures.Barrier as Barrier
import qualified Control.Concurrent.Futures.Futures as Futures
import Control.Concurrent

-- local finals
oneSecond = 1000000
 
    --------------------------------------------------------------------------------
-- | Example for barrier using 'Futures.withFuturesDo'.
barExampleF :: IO ()
barExampleF = Futures.withFuturesDo barExample

-- | Example for barrier: 4 threads syncinc on the barrier.
barExample :: IO ()
barExample = do
 putStrLn $ "4 Threads syncing on a barrier. This demo takes a bit time."
 bar <- Barrier.newBar 4
 Control.Concurrent.forkIO $ (doSomething 2 bar)
 Control.Concurrent.forkIO $ (doSomething 7 bar)
 Control.Concurrent.forkIO $ (doSomething 10 bar)
 Control.Concurrent.forkIO $ (doSomething 5 bar)
 Control.Concurrent.threadDelay $ 10 * oneSecond

--doSomething :: Int -> Barrier.Bar a -> IO ()
doSomething time bar = do
 Control.Concurrent.threadDelay $ time * oneSecond
 i <- Control.Concurrent.myThreadId
 putStrLn $ show i ++ " syncing."
 Barrier.syncBar bar
 return ()