withCStrOrNull ∷ Maybe String → (CString → IO a) → IO a
withCStrOrNull Nothing f = f nullPtr
withCStrOrNull (Just s) f = withCString s f
withCStrOrNull ∷ Maybe String → (CString → IO a) → IO a
withCStrOrNull Nothing f = f nullPtr
withCStrOrNull (Just s) f = withCString s f