[Haskell-cafe] Unbuffered character IO under Windows XP?

[Bulat Ziganshin]

Hello Ryan,

Saturday, December 29, 2007, 7:14:25 AM, you wrote:
> Is it possible to have unbuffered character IO under
> Windows XP?

> I have this problem as well and would love to hear if there is an answer.

once i had a hard day trying to figure out how to to the same in Unix.
in Windows, it was easy for me :)))  now my program contains:

-- |Ask decryption password using hidden input
ask_decryption_password = syncUI $ do
  withoutEcho $ do
  putStr "\n  Enter decryption password:"
  hFlush stdout
  getHiddenLine

-- |Input line not echoing it to the screen
getHiddenLine = go ""
  where go s = do c <- getHiddenChar
                  case c of
                    '\r' -> do putStrLn ""; return s
                    '\n' -> do putStrLn ""; return s
                    c    -> go (s++[c])


-- please note that FREEARC_WIN is specific to my program
#ifdef FREEARC_WIN

-- |Switch console into the hidden input mode
withoutEcho = id

-- |Input char without echoing it
getHiddenChar = liftM (chr.fromEnum) c_getch
foreign import ccall unsafe "conio.h getch"
   c_getch :: IO CChar

#else

-- |Input char without echoing it
getHiddenChar = getChar

-- |Switch console into the hidden input mode
withoutEcho action = do
  let setAttr attr = setTerminalAttributes stdInput attr Immediately
      disableEcho = do origAttr <- getTerminalAttributes stdInput
                       setAttr$ origAttr.$ flip withMode ProcessInput
                                        .$ flip withoutMode EnableEcho
                                        .$ flip withMode KeyboardInterrupts
                                        .$ flip withoutMode IgnoreBreak
                                        .$ flip withMode InterruptOnBreak
                       return origAttr
  --
  bracketCtrlBreak disableEcho setAttr (\_ -> action)

#endif



-- 
Best regards,
 Bulat                            mailto:Bulat.Ziganshin at gmail.com