P3951R1 — String Interpolation Objects
Barry Revzin
EWG
Revisions R1Apr 2026R0Jan 2026
The `std::format` approach to formatting offers many significant benefits over the prior `<iostream>`s approach that need not be revisited here. However, `<iostream>` does still have one significant advantage: ordering. It is easy to see at a glance with a long `std::cout` statement which pieces are to be formatted in which order. With `std::format`, as the amount of replacement fields increases, it becomes increasingly difficult to ensure that they are all correctly ordered.