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

 

I think there are some windows terminal settings that the GHC runtime should twiddle when you change the buffering state on stdin, but I don't know exactly what is involved.
 

  -- ryan
 

On 12/28/07, Peter Schmitz <haskell.ps@gmail.com> wrote:

module Main(main) where
import System.IO

main = do
   b1 <- hGetBuffering stdin
   print b1
   b2 <- hGetBuffering stdout
   print b2

   -- not sure if these help, or are needed
   hSetBuffering stdin  NoBuffering
   hSetBuffering stdout NoBuffering

   b1 <- hGetBuffering stdin
   print b1
   b2 <- hGetBuffering stdout
   print b2

   putStr "0"
   c <- getChar   -- echoes during input by default
   putStr "1"     -- want this output w/o hitting Enter
   hFlush stdout  -- adding this does not help
   putStrLn [c]

{------------------- Output:
E:\ghcTest>ghc --version
The Glorious Glasgow Haskell Compilation System, version 6.8.1

E:\ghcTest>ghc --make main
[1 of 1] Compiling Main             ( main.hs, main.o )
Linking main.exe ...

E:\ghcTest>main
LineBuffering
LineBuffering
NoBuffering
NoBuffering
0a
1a

E:\ghcTest>

----------------- Question:

Is it possible to have unbuffered character IO under
Windows XP?

I would like to be able to type a single character and have
the processing and IO continue without having to hit Enter.

I.e., rather than this
(had to hit Enter after typing the 'a' in '0a'):
0a
1a

I would like to have this
(without having to hit Enter after typing the char):
0a1a

I have tried a few combinations of hSetBuffering and
put/get Str/Char functions, without success.

NOTE:
I need to run under Windows XP, non-administrator account.
This test was run using the normal XP shell cmd.exe.

Thanks much in advance.
-- Peter
--------}

 

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