Hi everyone! I run into a problem with readProcessWithExitCode (from System.Process module). Basically what i want is to start an exe file, giving it some input on stdin and receiving the results on stdout. But id the stdin and out is bigger that 5000-7000 char (nondeterministically), i get commitAndReleaseBuffer exception and sometimes hFlush exception. I'm getting these errors with GHCi 6.12.3, if it matters. Have you guys any idea what causes the problem, to how to avoid it? Thanks Daniel Here is a dummy example, which produces the exception: Haskell code: import System.Process test = do result <- sequence $ Prelude.map (\x -> runOnce x) [1..10000] return () where runOnce :: Int -> IO [Int] runOnce i = do putStrLn (show i) a <- caller i b <- caller i return (a++b) caller a = do (exit_code,stdout) <- readProcessWithExitCode "a.exe" [show a] (unlines (map show [1..850])) return (read stdout) C code (for executable) #include <stdio.h> #include <complex.h> #include <stdlib.h> int main(int argc, char *argv[]) { printf("[%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d]",100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100, 100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100, 100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100, 100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100, 100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100, 100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100, 100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100); }