Backports

This page tracks status of papers aiming to update the released standard (high priority).

• C++20 Backports from C++23 in Library Evolution
• C++20 Backports from C++23 in Library

Papers

Title	Changes	Observable Effects	Status
P2372: Fixing locale handling in chrono formatters	- Make chrono formatters locale dependent by default. - Add L specifier for chrono localized formatting.	- Output of chrono objects changes.	LEWG
P2216: std::format improvements	- User code change from throwing to ill-formed, etc. - Reducing binary code size of format_to.	- Behavior of existing code. - Binary size.	Voted into C++23
P2281: Clarifying range adaptor objects	- Make customization point objects invocable regardless of their value category or cv qualification. - Makes silent dangling of certain kinds of bound range adaptor arguments ill-formed.	- Behavior of existing code.	Voted into C++23
P2328: join_view should join all views of ranges.	- join_view no longer default constructs the cached view when constructed. - join_view iterator increments no longer assigns to the inner view but destroys previous view and emplaces in place instead.	- Behaviour of existing code	Voted into C++23
P2325: Views should not be required to be default constructible	- A change in [range.view] concept definition. - Change views in ranges.	- Behavior of existing code.	Voted into C++23
P2210: Superior String Splitting	- A change in [range.split]. - Change views in ranges::split_view.	- Behavior of existing code.	Voted into C++23
P2367: Remove misuses of list-initialization from Clause 24	- Removes harmful uses of list initialization from a number of range adaptors. - Implied ordering guarantees of some range adaptors change.	- Clarifies unclear specification.	Voted into C++23
P2231: Missing constexpr in optional and variant	- Adds constexpr in missing places in optional and variant	- Doesn't affect existing code.	Voted into C++23