Library feature-test macros (C++20)

Each of following macros is defined if the header <version> or one of the corresponding headers specified in the table is included.

Macro name	Value	Header
__cpp_lib_addressof_constexpr	201603L	<memory>
__cpp_lib_allocator_traits_is_always_equal	201411L	<memory> <scoped_allocator> <string> <deque> <forward_list> <list> <vector> <map> <set> <unordered_map> <unordered_set>
__cpp_lib_any	201606L	<any>
__cpp_lib_apply	201603L	<tuple>
__cpp_lib_array_constexpr	201603L	<iterator> <array>
__cpp_lib_as_const	201510L	<utility>
__cpp_lib_atomic_is_always_lock_free	201603L	<atomic>
__cpp_lib_atomic_ref	201806L	<atomic>
__cpp_lib_bit_cast	201806L	<bit>
__cpp_lib_bind_front	201811L	<functional>
__cpp_lib_bool_constant	201505L	<type_traits>
__cpp_lib_bounded_array_traits	201902L	<type_traits>
__cpp_lib_boyer_moore_searcher	201603L	<functional>
__cpp_lib_byte	201603L	<cstddef>
__cpp_lib_char8_t	201811L	<atomic> <filesystem> <istream> <limits> <locale> <ostream> <string> <string_view>
__cpp_lib_chrono	201611L	<chrono>
__cpp_lib_clamp	201603L	<algorithm>
__cpp_lib_complex_udls	201309L	<complex>
__cpp_lib_concepts	201806L	<concepts>
__cpp_lib_constexpr_misc	201811L	<array> <functional> <iterator> <string_view> <tuple> <utility>
__cpp_lib_constexpr_swap_algorithms	201806L	<algorithm>
__cpp_lib_enable_shared_from_this	201603L	<memory>
__cpp_lib_erase_if	201811L	<string> <deque> <forward_list> <list> <vector> <map> <set> <unordered_map> <unordered_set>
__cpp_lib_exchange_function	201304L	<utility>
__cpp_lib_execution	201902L	<execution>
__cpp_lib_filesystem	201703L	<filesystem>
__cpp_lib_gcd_lcm	201606L	<numeric>
__cpp_lib_generic_associative_lookup	201304L	<map> <set>
__cpp_lib_generic_unordered_lookup	201811L	<unordered_map> <unordered_set>
__cpp_lib_generic_unordered_hash_lookup	201902L	<unordered_map> <unordered_set>
__cpp_lib_hardware_interference_size	201703L	<new>
__cpp_lib_has_unique_object_representations	201606L	<type_traits>
__cpp_lib_hypot	201603L	<cmath>
__cpp_lib_incomplete_container_elements	201505L	<forward_list> <list> <vector>
__cpp_lib_integer_sequence	201304L	<utility>
__cpp_lib_integral_constant_callable	201304L	<type_traits>
__cpp_lib_invoke	201411L	<functional>
__cpp_lib_interpolate	201902L	<cmath> <numeric>
__cpp_lib_is_constant_evaluated	201811L	<type_traits>
__cpp_lib_is_aggregate	201703L	<type_traits>
__cpp_lib_is_final	201402L	<type_traits>
__cpp_lib_is_invocable	201703L	<type_traits>
__cpp_lib_is_null_pointer	201309L	<type_traits>
__cpp_lib_is_swappable	201603L	<type_traits>
__cpp_lib_launder	201606L	<new>
__cpp_lib_list_remove_return_type	201806L	<forward_list> <list>
__cpp_lib_logical_traits	201510L	<type_traits>
__cpp_lib_make_from_tuple	201606L	<tuple>
__cpp_lib_make_reverse_iterator	201402L	<iterator>
__cpp_lib_make_unique	201304L	<memory>
__cpp_lib_map_try_emplace	201411L	<map>
__cpp_lib_math_special_functions	201603L	<cmath>
__cpp_lib_memory_resource	201603L	<memory_resource>
__cpp_lib_node_extract	201606L	<map> <set> <unordered_map> <unordered_set>
__cpp_lib_nonmember_container_access	201411L	<iterator> <array> <deque> <forward_list> <list> <map> <regex> <set> <string> <unordered_map> <unordered_set> <vector>
__cpp_lib_not_fn	201603L	<functional>
__cpp_lib_null_iterators	201304L	<iterator>
__cpp_lib_optional	201606L	<optional>
__cpp_lib_parallel_algorithm	201603L	<algorithm> <numeric>
__cpp_lib_quoted_string_io	201304L	<iomanip>
__cpp_lib_ranges	201811L	<algorithm> <functional> <iterator> <memory> <ranges>
__cpp_lib_raw_memory_algorithms	201606L	<memory>
__cpp_lib_result_of_sfinae	201210L	<functional> <type_traits>
__cpp_lib_robust_nonmodifying_seq_ops	201304L	<algorithm>
__cpp_lib_sample	201603L	<algorithm>
__cpp_lib_scoped_lock	201703L	<mutex>
__cpp_lib_shared_mutex	201505L	<shared_mutex>
__cpp_lib_shared_ptr_arrays	201611L	<memory>
__cpp_lib_shared_ptr_weak_type	201606L	<memory>
__cpp_lib_shared_timed_mutex	201402L	<shared_mutex>
__cpp_lib_string_udls	201304L	<string>
__cpp_lib_string_view	201606L	<string> <string_view>
__cpp_lib_three_way_comparison	201711L	<compare>
__cpp_lib_to_chars	201611L	<utility>
__cpp_lib_transformation_trait_aliases	201304L	<type_traits>
__cpp_lib_transparent_operators	201510L	<memory> <functional>
__cpp_lib_tuple_element_t	201402L	<tuple>
__cpp_lib_tuples_by_type	201304L	<utility> <tuple>
__cpp_lib_type_trait_variable_templates	201510L	<type_traits>
__cpp_lib_uncaught_exceptions	201411L	<exception>
__cpp_lib_unordered_map_try_emplace	201411L	<unordered_map>
__cpp_lib_variant	201606L	<variant>
__cpp_lib_void_t	201411L	<type_traits>