diff --git a/src/libcollections/fmt.rs b/src/libcollections/fmt.rs index 80fa6d397c829..cb023bcb7a586 100644 --- a/src/libcollections/fmt.rs +++ b/src/libcollections/fmt.rs @@ -353,6 +353,10 @@ //! * `^` - the argument is center-aligned in `width` columns //! * `>` - the argument is right-aligned in `width` columns //! +//! Note that alignment may not be implemented by some types. A good way +//! to ensure padding is applied is to format your input, then use this +//! resulting string to pad your output. +//! //! ## Sign/#/0 //! //! These can all be interpreted as flags for a particular formatter.