Running processes concurrently
(Difference between revisions)
Latest revision as of 21:22, 23 June 2007
This example forks many processes in parallel, then waits for each process to exit. Finally, it prints the number of failures.
import System.Process import Control.Concurrent import System.Exit main = do let cmds = replicate 100 "sleep 10s" ps <- mapM runCommand cmds es <- mapM waitForProcess ps case length . filter (/= ExitSuccess) $ es of 0 -> putStrLn "All commands ran successfully." n -> putStrLn ("There were " ++ show n ++ " failures.")