3750. Too many papers bump __cpp_lib_format

Section: 17.3.2 [version.syn] Status: C++23 Submitter: Barry Revzin Opened: 2022-08-04 Last modified: 2023-11-22

Priority: Not Prioritized

View other active issues in [version.syn].

View all other issues in [version.syn].

View all issues with C++23 status.

Discussion:

As pointed out by Casey Carter, four papers approved at the recent July 2022 plenary:

• P2419R2 "Clarify handling of encodings in localized formatting of chrono types"

• P2508R1 "Expose std::basic-format-string<charT, Args...>"

• P2286R8 "Formatting Ranges"

• P2585R1 "Improve container default formatting"

all bump the value of __cpp_lib_format. We never accounted for all of these papers being moved at the same time, and these papers have fairly different implementation complexities.

Victor Zverovich suggests that we instead add __cpp_lib_format_ranges (with value 202207L) for the two formatting ranges papers (P2286 and P2585, which should probably be implemented concurrently anyway, since the latter modifies the former) and bump __cpp_lib_format for the other two, which are both minor changes.

We should do that.

[2022-08-23; Reflector poll]

Set status to Tentatively Ready after 12 votes in favour during reflector poll.

[2022-11-12 Approved at November 2022 meeting in Kona. Status changed: Voting → WP.]

Proposed resolution:

1. Modify 17.3.2 [version.syn] as indicated:

   #define __cpp_lib_format          202207L // also in <format>
   #define __cpp_lib_format_ranges   202207L // also in <format>