    {-# LANGUAGE CPP #-}

    module Network.Wai.Logger.IORef (
           IORef
         , newIORef
         , readIORef
         , writeIORef
         , atomicModifyIORef'
         ) where

    import Data.IORef

    #if !MIN_VERSION_base(4, 6, 0)
    atomicModifyIORef' :: IORef a -> (a -> (a,b)) -> IO b
    atomicModifyIORef' ref f = do
        b <- atomicModifyIORef ref
                (\x -> let (a, b) = f x
                        in (a, a `seq` b))
        b `seq` return b
    #endif