GetUserName windows api call via haskell's FFI!

getusername

{-# LANGUAGE ForeignFunctionInterface #-}
import System.Win32.Types

import Foreign
import Foreign.C

foreign import stdcall unsafe "windows.h GetUserNameW"
  c_GetUserName :: LPTSTR -> LPDWORD -> IO Bool
  
getUserName :: IO String
getUserName =
  allocaArray 512 $ \ c_str -> do
  with 512 $ \ c_len -> do
  failIfFalse_ "GetUserName" $ c_GetUserName c_str c_len
  peekTString c_str

-- ghci -ladvapi32