I don't really understand getContents. (Does anyone?) I have some code here (far too large to submit). If I do (on Linux, ghc4.08.1, both with and without optimisation) ------------------ contents <- hGetContents handle seq (last contents) (hClose handle) ------------------ the code works. However I looked at the manual and it seems that hClose should force the whole of contents to be read anyway. So I changed it to ------------------ contents <- hGetContents handle hClose handle ------------------ and then the code doesn't work. If these are meant to be the same, then we have a GHC bug. If not, could someone explain in words of one syllable why not? PS - if you want the source code you'll have to download and compile the whole of UniForM!!