I seem to have some problems understanding preemptive getLine behaviour on cygwin, and wonder whether this is a known/fixed bug/feature (I haven't switched to ghc-6.. yet), or whether anyone has experience with this (behaviour on solaris, with an even older ghc is more or less as expected). Claus -- consider the following example. compile, run, and whenever the -- program waits for input, enter the next natural number, starting -- from 1. note that the program preempts the first input and may -- or may not accept input after the second output.. module Main where import IO main = do hGetBuffering stdin >>= print hGetLine stdin >>= print hGetLine stdin >>= print ------- win98, cygwin $ ./Getline LineBuffering "" 1 "1" $ cat | ./Getline BlockBuffering Nothing 1 "1" 2 "2" 3 $ ghc --version The Glorious Glasgow Haskell Compilation System, version 5.04.2 ------- solaris $ ./GetLine LineBuffering 1 "1" 2 "2" $ cat | ./GetLine BlockBuffering Nothing 1 "1" 2 "2" 3 $ ghc --version The Glorious Glasgow Haskell Compilation System, version 5.02.3