Create a temporary directory in Haskell

What is the proper way to safely create a temporary directory in Haskell? System.IO offers ways to create temporary files, but I can't fin开发者_开发技巧d anything that does the same for directories, neither there nor in System.Directory, System.Posix.Directory, nor System.Posix.Temp. Is there a function I'm overlooking, or do I need to write one myself? (And if so, are there any dangers to avoid, like there are with creating temporary files?)

For working specifically with Unix systems, the Unixutils package contains such a function:

withTemporaryDirectory :: FilePath -> (FilePath -> IO a) -> IO a

If you need it to work on both Windows and Unix systems, you'll want to use the temporary package instead. It has the same function with a slightly different type signature:

withTemporaryDirectory :: FilePath -> String -> (FilePath -> IO a) -> IO a

You could look at the Distribution.Compat.TempFile module of the Cabal source for an example. It defines createTempDirectory as follows (where c_getpid and mkPrivateDir are platform-specific):

createTempDirectory :: FilePath -> String -> IO FilePath
createTempDirectory dir template = do
  pid <- c_getpid
  findTempName pid
  where
    findTempName x = do
      let dirpath = dir </> template ++ show x
      r <- try $ mkPrivateDir dirpath
      case r of
        Right _ -> return dirpath
        Left  e | isAlreadyExistsError e -> findTempName (x+1)
                | otherwise              -> ioError e

The fact that Cabal defines this function suggests that there's not a standard way to do it.

As suggested by @Nikita Volkov, I am posting the comment of @Thomas M. DuBuisson as a separate answer:

Use the temporary package. It provides a convenient platform-independent API for using temporary files and directories. The temporary files and directories are automatically deleted after use.