Re: [Haskell-cafe] After `readFile`, why cannot i `writeFile` ?

zaxis writes:

hitSSQ :: String -> [Int] -> IO () hitSSQ no hitNum = do let newNum = unwords $ [no] ++ map (\n -> show n) hitNum hitNums <- fmap lines $ readFile "test.txt" writeFile "test.txt" $ unlines $ hitNums ++ [newNum]

*** Exception: test.txt: openFile: resource busy (file is locked)

You're currently reading the file; finish reading it and close it before you write over it (or else use WriteRead mode or whatever it's called and call openFile explicitly rather than using readFile and writeFile). -- Ivan Lazar Miljenovic Ivan.Miljenovic@gmail.com IvanMiljenovic.wordpress.com