FYI: FreeBSD main's llvm17: c++ feature macro status (what is reported to match an older vintage)

version_dump.cpp is taken from part of the page:

https://en.cppreference.com/w/cpp/feature_test

(The program does not output the "L" suffix and adds a "-" separator to make year
and month easier to notice compared to the encodings in the actual feature macros.)

From an amd64 context:

# c++ -std=c++26 -pedantic -Wall -Wextra version_dump.cpp
# ./a.out | grep -E '(/| < )' | grep -v '\-------'
C++11 CORE (20/20)
C++14 CORE (8/9)
C++14 LIB (20/20)
C++17 CORE (19/20)
C++17 LIB (44/49)
C++20 CORE (14/18)
__cpp_concepts                                2019-07  <  2020-02
__cpp_deduction_guides                        2017-03  <  2019-07
__cpp_nontype_template_args                   2014-11  <  2019-11
C++20 LIB (54/67)
__cpp_lib_chrono                              2016-11  <  2019-07
__cpp_lib_variant                             2021-02  <  2021-06
C++23 CORE (6/10)
__cpp_implicit_move                           2020-11  <  2022-07
__cpp_range_based_for                         2016-03  <  2022-11
C++23 LIB (21/64)
__cpp_lib_allocate_at_least                   2021-06  <  2023-02
__cpp_lib_barrier                             2019-07  <  2023-02
__cpp_lib_concepts                            2020-02  <  2022-07
__cpp_lib_ranges                              2022-07  <  2023-02
__cpp_lib_shift                               2018-06  <  2022-02
C++26 CORE (2/3)
C++26 LIB (2/39)
__cpp_lib_chrono                              2016-11  <  2023-06
__cpp_lib_constexpr_algorithms                2018-06  <  2023-06
__cpp_lib_constexpr_complex                   2017-11  <  2023-06
__cpp_lib_not_fn                              2016-03  <  2023-06
__cpp_lib_variant                             2021-02  <  2023-06
ALL CORE MACROS UP TO C++26 (56/67)
__cpp_concepts                                2019-07  <  2020-02
__cpp_deduction_guides                        2017-03  <  2019-07
__cpp_implicit_move                           2020-11  <  2022-07
__cpp_nontype_template_args                   2014-11  <  2019-11
__cpp_range_based_for                         2016-03  <  2022-11
ALL LIB MACROS UP TO C++26 (124/214)
__cpp_lib_allocate_at_least                   2021-06  <  2023-02
__cpp_lib_barrier                             2019-07  <  2023-02
__cpp_lib_chrono                              2016-11  <  2023-06
__cpp_lib_concepts                            2020-02  <  2022-07
__cpp_lib_constexpr_algorithms                2018-06  <  2023-06
__cpp_lib_constexpr_complex                   2017-11  <  2023-06
__cpp_lib_not_fn                              2016-03  <  2023-06
__cpp_lib_ranges                              2022-07  <  2023-02
__cpp_lib_shift                               2018-06  <  2022-02
__cpp_lib_variant                             2021-02  <  2023-06
ATTRIBUTES (9/10)

===
Mark Millard
marklmi at yahoo.com