Re: [Haskell-cafe] getChar
Cetin Sert wrote: is there a version of getChar that doesn't buffer keyboard input until enter is pressed? Look into hSetBuffering (module System.IO or IO). As a quick start: hSetBuffering stdin NoBuffering ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] getChar
Hi, is there a version of getChar that doesn't buffer keyboard input until enter is pressed? specialReadln :: IO String specialReadln = do c ← getChar if c == '#' then do return [] else do cs ← specialReadln return (c:cs) I want the input process to terminate when '#' or any other specific key has been pressed. Best Regards, Cetin Sert ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] getChar + System.Cmd.system + threads causes hangups
Here is a version that works fine:
myRawSystem cmd args = do
(inP, outP, errP, pid) <- runInteractiveProcess cmd args Nothing Nothing
hClose inP
os <- pGetContents outP
es <- pGetContents errP
ec <- waitForProcess pid
case ec of
ExitSuccess -> return ()
ExitFailure e ->
do hPutStrLn stderr ("Running process "++unwords (cmd:args)++" FAILED
("++show e++")")
hPutStrLn stderr os
hPutStrLn stderr es
hPutStrLn stderr ("Raising error...")
fail "Running external command failed"
pGetContents h = do
mv <- newEmptyMVar
let put [] = putMVar mv []
put xs = last xs `seq` putMVar mv xs
forkIO (hGetContents h >>= put)
takeMVar mv
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[Haskell-cafe] getChar + System.Cmd.system + threads causes hangups
Hello Using system or any variant of it from System.Process seems broken in multithreaded environments. This example will fail with and without -threaded. When run the program will print "hello: start" and then freeze. After pressing enter (the first getChar) System.Cmd.system will complete, but without that it will freeze for all eternity. What is the best way to fix this? I could use System.Posix, but that would lose windows portablity which is needed. import Control.Concurrent import System.Cmd main = do forkIO (threadDelay 10 >> hello) getChar getChar hello = do putStrLn "hello: start" system "echo hello world!" putStrLn "hello: done" - Einar Karttunen ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
