Does anyone know if the new System.Timeout.timeout combinator can wakeup from System.Process.waitForProcess? I have not been able to make this work, and it appears as though the timeout exception is thrown only after waitForProcess returns normally (if it ever does). I am using Windows and GHC 6.8.1. import Control.Concurrent import System.IO import System.IO.Error(isEOFError) import System.Process(runInteractiveProcess, waitForProcess, ProcessHandle) import System.Timeout(timeout) halfSecond = 500000 example = timeout halfSecond sleepy sleepy = do (inp,out,err,pid) <- runInteractiveProcess "sleep.exe" ["10"] Nothing Nothing forkOS (ioGobbler out) forkOS (ioGobbler err) waitForProcess pid -- CAN timeout INTERRUPT THIS? return "PROCESS FINISHED" ioGobbler :: Handle -> IO () ioGobbler h = catch (ioDiscarder h) eofHandler ioDiscarder :: Handle -> IO () ioDiscarder h = do hGetChar h >> ioDiscarder h eofHandler :: IOError -> IO () eofHandler e | isEOFError e = return () | otherwise = ioError e Executing `example' from ghci will spawn (sleep.exe 10) which sleeps for 10 seconds. The timeout should happen in half a second (giving the thread time to get blocked into waitForProcess). However, instead, things block for ten seconds (until sleep.exe exits and waitForProcess returns normally). While a workaround is to spin and sleep with the getProcessExitCode and threadDelay, it seems like an inappropriate hack. The documentation for timeout lists some functions that are interruptible, but is not mean to be a complete list. Thanks all, - Tim -- View this message in context: http://www.nabble.com/timeout-and-waitForProcess-tf4847280.html#a13868823 Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com.