libc++ Format Status¶
Overview¶
This document contains the status of the C++20 Format library in libc++. It is used to track both the status of the sub-projects of the Format library and who is assigned to these sub-projects. This is imperative to effective implementation so that work is not duplicated and implementors are not blocked by each other.
If you are interested in contributing to the libc++ Format library, please send a message to the #libcxx channel in the LLVM discord. Please do not start working on any of the assigned items below.
Sub-Projects in the Format library¶
| Section | Description | Dependencies | Assignee | Patch | Status | First released version | |
|---|---|---|---|---|---|---|---|
| [charconv.to.chars] | Fix integral conformance | Mark de Wever | D100722 | Complete | Clang 13 | ||
| [charconv.to.chars] | Add floating-point conversion | D100722 | Mark de Wever (Code provided by Stephan T. Lavavej of Microsoft) | D70631 | In progress | ||
| [format.error] | Class format_error | Mark de Wever | D92214 | Complete | Clang 13 | ||
| [format.parse.ctx] | Class template basic_format_parse_context | Mark de Wever | D93166 | Complete | Clang 13 | ||
| [format.context] | Class template basic_format_context | Mark de Wever | D103357 | Review | |||
| [format.args] | Class template basic_format_args | Mark de Wever | D103357 | Review | |||
| [format.arg] | Class template basic_format_arg | Mark de Wever | D103357 | Review | |||
| [format.arg] | Class template basic_format_arg - handle | ||||||
| [format.arg] | Class template basic_format_arg - pointers | ||||||
| [format.arg.store] | Class template format-arg-store | Mark de Wever | D103357 | Review | |||
| [format.formatter.spec] | Formatter specializations - character types | Mark de Wever | D96664 D103466 | Review | |||
| [format.formatter.spec] | Formatter specializations - string types | Mark de Wever | D96664 D103425 | Review | |||
| [format.formatter.spec] | Formatter specializations - boolean type | Mark de Wever | D96664 D103670 | Review | |||
| [format.formatter.spec] | Formatter specializations - integral types | Mark de Wever | D96664 D103433 | Review | |||
| [format.formatter.spec] | Formatter specializations - floating-point types | D70631 | Mark de Wever | D96664 | Review | ||
| [format.formatter.spec] | Formatter specializations - pointer types | ||||||
| [format.string.std] | Standard format specifiers - character types | Mark de Wever | D103368 | Review | |||
| [format.string.std] | Standard format specifiers - string types | D103379 | Mark de Wever | D103368 D103413 | Review | ||
| [format.string.std] | Standard format specifiers - boolean type | D103379 | Mark de Wever | D103368 D103413 | Review | ||
| [format.string.std] | Standard format specifiers - integral types | Mark de Wever | D103368 | Review | |||
| [format.string.std] | Standard format specifiers - floating-point types | Mark de Wever | |||||
| [format.string.std] | Standard format specifiers - pointer types | Mark de Wever | |||||
| [format.functions] | Format functions - format(string_view fmt, const Args&… args); | Mark de Wever | D96664 | Review | |||
| [format.functions] | Format functions - format(wstring_view fmt, const Args&… args); | Mark de Wever | D96664 | Review | |||
| [format.functions] | Format functions - format(const locale& loc, string_view fmt, const Args&… args); | Mark de Wever | D96664 | Review | |||
| [format.functions] | Format functions - format(const locale& loc, wstring_view fmt, const Args&… args); | Mark de Wever | D96664 | Review | |||
| [format.functions] | Format functions - vformat(string_view fmt, format_args args); | Mark de Wever | D96664 | Review | |||
| [format.functions] | Format functions - vformat(wstring_view fmt, wformat_args args); | Mark de Wever | D96664 | Review | |||
| [format.functions] | Format functions - vformat(const locale& loc, string_view fmt, format_args args); | Mark de Wever | D96664 | Review | |||
| [format.functions] | Format functions - vformat(const locale& loc, wstring_view fmt, wformat_args args); | Mark de Wever | D96664 | Review | |||
| [format.functions] | Format functions - format_to(Out out, wstring_view fmt, const Args&… args); | Mark de Wever | D96664 | Review | |||
| [format.functions] | Format functions - format_to(Out out, const locale& loc, wstring_view fmt, const Args&… args); | Mark de Wever | D96664 | Review | |||
| [format.functions] | Format functions - vformat_to(Out out, string_view fmt, format_args_t<type_identity_t<Out>, char> args); | Mark de Wever | D96664 | Review | |||
| [format.functions] | Format functions - vformat_to(Out out, wstring_view fmt, format_args_t<type_identity_t<Out>, char> args); | Mark de Wever | D96664 | Review | |||
| [format.functions] | Format functions - vformat_to(Out out, const locale& loc, string_view fmt, format_args_t<type_identity_t<Out>, char> args); | Mark de Wever | D96664 | Review | |||
| [format.functions] | Format functions - vformat_to(Out out, const locale& loc, wstring_view fmt,format_args_t<type_identity_t<Out>, wchar_t> args); | Mark de Wever | D96664 | Review | |||
| [format.functions] | Format functions - format_to_n(Out out, iter_difference_t<Out> n, string_view fmt, const Args&… args); | Mark de Wever | D96664 | Review | |||
| [format.functions] | Format functions - format_to_n(Out out, iter_difference_t<Out> n, wstring_view fmt, const Args&… args); | Mark de Wever | D96664 | Review | |||
| [format.functions] | Format functions - format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n, const locale& loc, string_view fmt, const Args&… args); | Mark de Wever | D96664 | Review | |||
| [format.functions] | Format functions - format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n, const locale& loc, wstring_view fmt, const Args&… args); | Mark de Wever | D96664 | Review | |||
| [format.functions] | Format functions - formatted_size(string_view fmt, const Args&… args); | Mark de Wever | D96664 | Review | |||
| [format.functions] | Format functions - formatted_size(wstring_view fmt, const Args&… args); | Mark de Wever | D96664 | Review | |||
| [format.functions] | Format functions - formatted_size(const locale& loc, string_view fmt, const Args&… args); | Mark de Wever | D96664 | Review | |||
| [format.functions] | Format functions - formatted_size(const locale& loc, wstring_view fmt, const Args&… args); | Mark de Wever | D96664 | Review | |||
| [format.functions] | Format functions - Implement locale support | Mark de Wever | In progress | ||||
| [format.functions] | Format functions - Improve performance format_to_n | Mark de Wever | |||||
| [format.functions] | Format functions - Improve performance formatted size | Mark de Wever |
Misc. Items and TODOs¶
(Please mark all Format-related TODO comments with the string TODO FMT, so we
can find them easily.)
- C++23 may break the ABI with P2216. This ABI break may be backported to C++20. Therefore the library will not be available on platforms where the ABI break is an issue.
Paper and Issue Status¶
| Number | Name | Assignee | Patch | Status | First released version |
|---|---|---|---|---|---|
| P0645 | Text Formatting | Mark de Wever | Partial | ||
| P1652 | Printf corner cases in std::format | Mark de Wever | D103433 | Review | |
| P1892 | Extended locale-specific presentation specifiers for std::format | Mark de Wever | D103368 | Review | |
| P1868 | width: clarifying units of width and precision in std::format (Implements the unicode support.) | Mark de Wever | D103413 D103425 D103670 | Review | |
| P2216 | std::format improvements | ||||
| LWG-3242 | std::format: missing rules for arg-id in width and precision | Mark de Wever | D103368 | Review | |
| LWG-3243 | std::format and negative zeroes | ||||
| LWG-3246 | What are the constraints on the template parameter of basic_format_arg? | ||||
| LWG-3248 | std::format #b, #B, #o, #x, and #X presentation types misformat negative numbers | Mark de Wever | D103433 | Review | |
| LWG-3250 | std::format: # (alternate form) for NaN and inf | ||||
| LWG-3327 | Format alignment specifiers vs. text direction | Nothing To Do | |||
| LWG-3340 | Formatting functions should throw on argument/format string mismatch in [format.functions] | ||||
| LWG-3371 | visit_format_arg and make_format_args are not hidden friends | Mark de Wever | D103357 | Review | |
| LWG-3372 | vformat_to should not try to deduce Out twice | ||||
| LWG-3373 | {to,from}_chars_result and format_to_n_result need the ‘we really mean what we say’ | ||||
| LWG-3462 | §[formatter.requirements]: Formatter requirements forbid use of fc.arg() | ||||
| LWG-3539 | format_to must not copy models of output_iterator<const charT&> | ||||
| LWG-3540 | §[format.arg] There should be no const in basic_format_arg(const T* p) | ||||
| LWG-3541 | indirectly_readable_traits should be SFINAE-friendly for all types | ||||
| LWG-3542 | basic_format_arg mishandles basic_string_view with custom traits | ||||
| LWG-3544 | format-arg-store::args is unintentionally not exposition-only | ||||
| P1361 | Integration of chrono with text formatting | ||||
| LWG-3218 | Modifier for %d parse flag does not match POSIX and format specification | ||||
| LWG-3230 | Format specifier %y/%Y is missing locale alternative versions | ||||
| LWG-3241 | chrono-spec grammar ambiguity in [time.format] | ||||
| LWG-3262 | Formatting of negative durations is not specified | ||||
| LWG-3270 | Parsing and formatting %j with durations | ||||
| LWG-3272 | %I%p should parse/format duration since midnight | ||||
| LWG-3332 | Issue in [time.format] |