Library feature-test macros (since 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	Free- standing
`__cpp_lib_adaptor_iterator_pair_constructor`	202106L	`<stack>` `<queue>`
`__cpp_lib_addressof_constexpr`	201603L	`<memory>`	Yes
`__cpp_lib_algorithm_default_value_type`	202403L	`<algorithm>` `<ranges>` `<string>` `<deque>` `<list>` `<forward_list>` `<vector>`
`__cpp_lib_algorithm_iterator_requirements`	202207L	`<algorithm>` `<numeric>` `<memory>`
`__cpp_lib_allocate_at_least`	202302L	`<memory>`
`__cpp_lib_allocator_traits_is_always_equal`	201411L	`<memory>` `<scoped_allocator>` `<string>` `<deque>` `<forward_list>` `<list>` `<vector>` `<map>` `<set>` `<unordered_map>` `<unordered_set>`	Yes
`__cpp_lib_any`	201606L	`<any>`
`__cpp_lib_apply`	201603L	`<tuple>`	Yes
`__cpp_lib_array_constexpr`	201811L	`<iterator>` `<array>`
`__cpp_lib_as_const`	201510L	`<utility>`	Yes
`__cpp_lib_associative_heterogeneous_erasure`	202110L	`<map>` `<set>` `<unordered_map>` `<unordered_set>`
`__cpp_lib_associative_heterogeneous_insertion`	202306L	`<map>` `<set>` `<unordered_map>` `<unordered_set>`
`__cpp_lib_assume_aligned`	201811L	`<memory>`	Yes
`__cpp_lib_atomic_flag_test`	201907L	`<atomic>`	Yes
`__cpp_lib_atomic_float`	201711L	`<atomic>`	Yes
`__cpp_lib_atomic_is_always_lock_free`	201603L	`<atomic>`	Yes
`__cpp_lib_atomic_lock_free_type_aliases`	201907L	`<atomic>`
`__cpp_lib_atomic_min_max`	202403L	`<atomic>`	Yes
`__cpp_lib_atomic_ref`	201806L	`<atomic>`	Yes
`__cpp_lib_atomic_shared_ptr`	201711L	`<memory>`
`__cpp_lib_atomic_value_initialization`	201911L	`<atomic>` `<memory>`	Yes
`__cpp_lib_atomic_wait`	201907L	`<atomic>`	Yes
`__cpp_lib_barrier`	202302L	`<barrier>`
`__cpp_lib_bind_back`	202306L	`<functional>`	Yes
`__cpp_lib_bind_front`	202306L	`<functional>`	Yes
`__cpp_lib_bit_cast`	201806L	`<bit>`	Yes
`__cpp_lib_bitops`	201907L	`<bit>`	Yes
`__cpp_lib_bitset`	202306L	`<bitset>`
`__cpp_lib_bool_constant`	201505L	`<type_traits>`	Yes
`__cpp_lib_bounded_array_traits`	201902L	`<type_traits>`	Yes
`__cpp_lib_boyer_moore_searcher`	201603L	`<functional>`
`__cpp_lib_byte`	201603L	`<cstddef>`	Yes
`__cpp_lib_byteswap`	202110L	`<bit>`	Yes
`__cpp_lib_char8_t`	201907L	`<atomic>` `<filesystem>` `<istream>` `<limits>` `<locale>` `<ostream>` `<string>` `<string_view>`	Yes
`__cpp_lib_chrono`	202306L	`<chrono>`
`__cpp_lib_chrono_udls`	201304L	`<chrono>`
`__cpp_lib_clamp`	201603L	`<algorithm>`
`__cpp_lib_common_reference`	202302L	`<type_traits>`
`__cpp_lib_common_reference_wrapper`	202302L	`<functional>`
`__cpp_lib_complex_udls`	201309L	`<complex>`
`__cpp_lib_concepts`	202207L	`<concepts>` `<compare>`	Yes
`__cpp_lib_constexpr_algorithms`	202306L	`<algorithm>` `<utility>`
`__cpp_lib_constexpr_bitset`	202207L	`<bitset>`
`__cpp_lib_constexpr_charconv`	202207L	`<charconv>`
`__cpp_lib_constexpr_cmath`	202306L	`<cmath>` `<cstdlib>`
`__cpp_lib_constexpr_complex`	202306L	`<complex>`
`__cpp_lib_constexpr_dynamic_alloc`	201907L	`<memory>`
`__cpp_lib_constexpr_functional`	201907L	`<functional>`	Yes
`__cpp_lib_constexpr_iterator`	201811L	`<iterator>`	Yes
`__cpp_lib_constexpr_memory`	202202L	`<memory>`	Yes
`__cpp_lib_constexpr_new`	202406L	`<new>`	Yes
`__cpp_lib_constexpr_numeric`	201911L	`<numeric>`
`__cpp_lib_constexpr_string`	201907L	`<string>`
`__cpp_lib_constexpr_string_view`	201811L	`<string_view>`
`__cpp_lib_constexpr_tuple`	201811L	`<tuple>`	Yes
`__cpp_lib_constexpr_typeinfo`	202106L	`<typeinfo>`	Yes
`__cpp_lib_constexpr_utility`	201811L	`<utility>`	Yes
`__cpp_lib_constexpr_vector`	201907L	`<vector>`
`__cpp_lib_constrained_equality`	202403L	`<utility>` `<tuple>` `<optional>` `<variant>`	Yes
`__cpp_lib_containers_ranges`	202202L	`<vector>` `<list>` `<forward_list>` `<map>` `<set>` `<unordered_map>` `<unordered_set>` `<deque>` `<queue>` `<stack>` `<string>`
`__cpp_lib_copyable_function`	202306L	`<functional>`
`__cpp_lib_coroutine`	201902L	`<coroutine>`
`__cpp_lib_debugging`	202403L	`<debugging>`	Yes
`__cpp_lib_destroying_delete`	201806L	`<new>`	Yes
`__cpp_lib_enable_shared_from_this`	201603L	`<memory>`
`__cpp_lib_endian`	201907L	`<bit>`	Yes
`__cpp_lib_erase_if`	202002L	`<string>` `<deque>` `<forward_list>` `<list>` `<vector>` `<map>` `<set>` `<unordered_map>` `<unordered_set>`
`__cpp_lib_exchange_function`	201304L	`<utility>`	Yes
`__cpp_lib_execution`	201902L	`<execution>`
`__cpp_lib_expected`	202211L	`<expected>`
`__cpp_lib_filesystem`	201703L	`<filesystem>`
`__cpp_lib_flat_map`	202207L	`<flat_map>`
`__cpp_lib_flat_set`	202207L	`<flat_set>`
`__cpp_lib_format`	202311L	`<format>`
`__cpp_lib_format_ranges`	202207L	`<format>`
`__cpp_lib_format_path`	202403L	`<filesystem>`
`__cpp_lib_format_uchar`	202311L	`<format>`
`__cpp_lib_formatters`	202302L	`<stacktrace>` `<thread>`
`__cpp_lib_forward_like`	202207L	`<utility>`	Yes
`__cpp_lib_freestanding_algorithm`	202311L	`<algorithm>`	Yes
`__cpp_lib_freestanding_array`	202311L	`<array>`	Yes
`__cpp_lib_freestanding_char_traits`	202306L	`<string>`	Yes
`__cpp_lib_freestanding_charconv`	202306L	`<charconv>`	Yes
`__cpp_lib_freestanding_cstdlib`	202306L	`<cstdlib>` `<cmath>`	Yes
`__cpp_lib_freestanding_cstring`	202311L	`<cstring>`	Yes
`__cpp_lib_freestanding_cwchar`	202306L	`<cwchar>`	Yes
`__cpp_lib_freestanding_errc`	202306L	`<cerrno>` `<system_error>`	Yes
`__cpp_lib_freestanding_expected`	202311L	`<expected>`	Yes
`__cpp_lib_freestanding_feature_test_macros`	202306L		Yes
`__cpp_lib_freestanding_functional`	202306L	`<functional>`	Yes
`__cpp_lib_freestanding_iterator`	202306L	`<iterator>`	Yes
`__cpp_lib_freestanding_mdspan`	202311L	`<mdspan>`	Yes
`__cpp_lib_freestanding_memory`	202306L	`<memory>`	Yes
`__cpp_lib_freestanding_numeric`	202311L	`<numeric>`	Yes
`__cpp_lib_freestanding_optional`	202311L	`<optional>`	Yes
`__cpp_lib_freestanding_ranges`	202306L	`<ranges>`	Yes
`__cpp_lib_freestanding_ratio`	202306L	`<ratio>`	Yes
`__cpp_lib_freestanding_string_view`	202311L	`<string_view>`	Yes
`__cpp_lib_freestanding_tuple`	202306L	`<tuple>`	Yes
`__cpp_lib_freestanding_utility`	202306L	`<utility>`	Yes
`__cpp_lib_freestanding_variant`	202311L	`<variant>`	Yes
`__cpp_lib_fstream_native_handle`	202306L	`<fstream>`
`__cpp_lib_function_ref`	202306L	`<functional>`
`__cpp_lib_gcd_lcm`	201606L	`<numeric>`
`__cpp_lib_generator`	202207L	`<generator>`
`__cpp_lib_generic_associative_lookup`	201304L	`<map>` `<set>`
`__cpp_lib_generic_unordered_lookup`	201811L	`<unordered_map>` `<unordered_set>`
`__cpp_lib_hardware_interference_size`	201703L	`<new>`	Yes
`__cpp_lib_has_unique_object_representations`	201606L	`<type_traits>`	Yes
`__cpp_lib_hazard_pointer`	202306L	`<hazard_pointer>`
`__cpp_lib_hypot`	201603L	`<cmath>`
`__cpp_lib_incomplete_container_elements`	201505L	`<forward_list>` `<list>` `<vector>`
`__cpp_lib_inplace_vector`	202406L	`<inplace_vector>`
`__cpp_lib_int_pow2`	202002L	`<bit>`	Yes
`__cpp_lib_integer_comparison_functions`	202002L	`<utility>`
`__cpp_lib_integer_sequence`	201304L	`<utility>`	Yes
`__cpp_lib_integral_constant_callable`	201304L	`<type_traits>`	Yes
`__cpp_lib_interpolate`	201902L	`<cmath>` `<numeric>`
`__cpp_lib_invoke`	201411L	`<functional>`	Yes
`__cpp_lib_invoke_r`	202106L	`<functional>`	Yes
`__cpp_lib_ios_noreplace`	202207L	`<ios>`
`__cpp_lib_is_aggregate`	201703L	`<type_traits>`	Yes
`__cpp_lib_is_constant_evaluated`	201811L	`<type_traits>`	Yes
`__cpp_lib_is_final`	201402L	`<type_traits>`	Yes
`__cpp_lib_is_implicit_lifetime`	202302L	`<type_traits>`
`__cpp_lib_is_invocable`	201703L	`<type_traits>`	Yes
`__cpp_lib_is_layout_compatible`	201907L	`<type_traits>`	Yes
`__cpp_lib_is_nothrow_convertible`	201806L	`<type_traits>`	Yes
`__cpp_lib_is_null_pointer`	201309L	`<type_traits>`	Yes
`__cpp_lib_is_pointer_interconvertible`	201907L	`<type_traits>`	Yes
`__cpp_lib_is_scoped_enum`	202011L	`<type_traits>`	Yes
`__cpp_lib_is_swappable`	201603L	`<type_traits>`	Yes
`__cpp_lib_is_virtual_base_of`	202406L	`<type_traits>`
`__cpp_lib_is_within_lifetime`	202306L	`<type_traits>`
`__cpp_lib_jthread`	201911L	`<stop_token>` `<thread>`
`__cpp_lib_latch`	201907L	`<latch>`
`__cpp_lib_launder`	201606L	`<new>`	Yes
`__cpp_lib_linalg`	202311L	`<linalg>`
`__cpp_lib_list_remove_return_type`	201806L	`<forward_list>` `<list>`
`__cpp_lib_logical_traits`	201510L	`<type_traits>`	Yes
`__cpp_lib_make_from_tuple`	201606L	`<tuple>`	Yes
`__cpp_lib_make_reverse_iterator`	201402L	`<iterator>`	Yes
`__cpp_lib_make_unique`	201304L	`<memory>`
`__cpp_lib_map_try_emplace`	201411L	`<map>`
`__cpp_lib_math_constants`	201907L	`<numbers>`
`__cpp_lib_math_special_functions`	201603L	`<cmath>`
`__cpp_lib_mdspan`	202406L	`<mdspan>`
`__cpp_lib_memory_resource`	201603L	`<memory_resource>`
`__cpp_lib_modules`	202207L		Yes
`__cpp_lib_move_iterator_concept`	202207L	`<iterator>`	Yes
`__cpp_lib_move_only_function`	202110L	`<functional>`
`__cpp_lib_node_extract`	201606L	`<map>` `<set>` `<unordered_map>` `<unordered_set>`
`__cpp_lib_nonmember_container_access`	201411L	`<array>` `<deque>` `<forward_list>` `<iterator>` `<list>` `<map>` `<regex>` `<set>` `<string>` `<unordered_map>` `<unordered_set>` `<vector>`	Yes
`__cpp_lib_not_fn`	202306L	`<functional>`	Yes
`__cpp_lib_null_iterators`	201304L	`<iterator>`	Yes
`__cpp_lib_optional`	202110L	`<optional>`
`__cpp_lib_optional_range_support`	202406L	`<optional>`	Yes
`__cpp_lib_out_ptr`	202311L	`<memory>`	Yes
`__cpp_lib_parallel_algorithm`	201603L	`<algorithm>` `<numeric>`
`__cpp_lib_philox_engine`	202406L	`<random>`
`__cpp_lib_polymorphic_allocator`	201902L	`<memory_resource>`
`__cpp_lib_print`	202406L	`<print>` `<ostream>`
`__cpp_lib_quoted_string_io`	201304L	`<iomanip>`
`__cpp_lib_ranges`	202406L	`<algorithm>` `<functional>` `<iterator>` `<memory>` `<ranges>`
`__cpp_lib_ranges_as_const`	202311L	`<ranges>`	Yes
`__cpp_lib_ranges_as_rvalue`	202207L	`<ranges>`	Yes
`__cpp_lib_ranges_cartesian_product`	202207L	`<ranges>`	Yes
`__cpp_lib_ranges_chunk`	202202L	`<ranges>`	Yes
`__cpp_lib_ranges_chunk_by`	202202L	`<ranges>`	Yes
`__cpp_lib_ranges_concat`	202403L	`<ranges>`	Yes
`__cpp_lib_ranges_contains`	202207L	`<algorithm>`
`__cpp_lib_ranges_enumerate`	202302L	`<ranges>`
`__cpp_lib_ranges_find_last`	202207L	`<algorithm>`
`__cpp_lib_ranges_fold`	202207L	`<algorithm>`
`__cpp_lib_ranges_generate_random`	202403L	`<random>`
`__cpp_lib_ranges_iota`	202202L	`<numeric>`
`__cpp_lib_ranges_join_with`	202202L	`<ranges>`	Yes
`__cpp_lib_ranges_repeat`	202207L	`<ranges>`	Yes
`__cpp_lib_ranges_slide`	202202L	`<ranges>`	Yes
`__cpp_lib_ranges_starts_ends_with`	202106L	`<algorithm>`
`__cpp_lib_ranges_stride`	202207L	`<ranges>`	Yes
`__cpp_lib_ranges_to_container`	202202L	`<ranges>`	Yes
`__cpp_lib_ranges_zip`	202110L	`<ranges>` `<tuple>` `<utility>`	Yes
`__cpp_lib_ratio`	202306L	`<ratio>`
`__cpp_lib_raw_memory_algorithms`	201606L	`<memory>`
`__cpp_lib_rcu`	202306L	`<rcu>`
`__cpp_lib_reference_from_temporary`	202202L	`<type_traits>`	Yes
`__cpp_lib_reference_wrapper`	202403L	`<functional>`	Yes
`__cpp_lib_remove_cvref`	201711L	`<type_traits>`	Yes
`__cpp_lib_result_of_sfinae`	201210L	`<functional>` `<type_traits>`	Yes
`__cpp_lib_robust_nonmodifying_seq_ops`	201304L	`<algorithm>`
`__cpp_lib_sample`	201603L	`<algorithm>`
`__cpp_lib_saturation_arithmetic`	202311L	`<numeric>`
`__cpp_lib_scoped_lock`	201703L	`<mutex>`
`__cpp_lib_semaphore`	201907L	`<semaphore>`
`__cpp_lib_senders`	202406L	`<execution>`
`__cpp_lib_shared_mutex`	201505L	`<shared_mutex>`
`__cpp_lib_shared_ptr_arrays`	201707L	`<memory>`
`__cpp_lib_shared_ptr_weak_type`	201606L	`<memory>`
`__cpp_lib_shared_timed_mutex`	201402L	`<shared_mutex>`
`__cpp_lib_shift`	202202L	`<algorithm>`
`__cpp_lib_smart_ptr_for_overwrite`	202002L	`<memory>`
`__cpp_lib_smart_ptr_owner_equality`	202306L	`<memory>`
`__cpp_lib_source_location`	201907L	`<source_location>`	Yes
`__cpp_lib_span`	202311L	`<span>`	Yes
`__cpp_lib_span_initializer_list`	202311L	`<span>`
`__cpp_lib_spanstream`	202106L	`<spanstream>`
`__cpp_lib_ssize`	201902L	`<iterator>`	Yes
`__cpp_lib_sstream_from_string_view`	202306L	`<sstream>`
`__cpp_lib_stacktrace`	202011L	`<stacktrace>`
`__cpp_lib_start_lifetime_as`	202207L	`<memory>`	Yes
`__cpp_lib_starts_ends_with`	201711L	`<string>` `<string_view>`
`__cpp_lib_stdatomic_h`	202011L	`<stdatomic.h>`
`__cpp_lib_string_contains`	202011L	`<string>` `<string_view>`
`__cpp_lib_string_resize_and_overwrite`	202110L	`<string>`
`__cpp_lib_string_udls`	201304L	`<string>`
`__cpp_lib_string_view`	202403L	`<string>` `<string_view>`
`__cpp_lib_submdspan`	202403L	`<mdspan>`
`__cpp_lib_syncbuf`	201803L	`<syncstream>`
`__cpp_lib_text_encoding`	202306L	`<text_encoding>`
`__cpp_lib_three_way_comparison`	201907L	`<compare>`	Yes
`__cpp_lib_to_address`	201711L	`<memory>`	Yes
`__cpp_lib_to_array`	201907L	`<array>`
`__cpp_lib_to_chars`	202306L	`<charconv>`
`__cpp_lib_to_string`	202306L	`<string>`
`__cpp_lib_to_underlying`	202102L	`<utility>`	Yes
`__cpp_lib_transformation_trait_aliases`	201304L	`<type_traits>`	Yes
`__cpp_lib_transparent_operators`	201510L	`<memory>` `<functional>`	Yes
`__cpp_lib_tuple_element_t`	201402L	`<tuple>`	Yes
`__cpp_lib_tuple_like`	202311L	`<utility>` `<tuple>` `<map>` `<unordered_map>`
`__cpp_lib_tuples_by_type`	201304L	`<utility>` `<tuple>`	Yes
`__cpp_lib_type_identity`	201806L	`<type_traits>`	Yes
`__cpp_lib_type_trait_variable_templates`	201510L	`<type_traits>`	Yes
`__cpp_lib_uncaught_exceptions`	201411L	`<exception>`	Yes
`__cpp_lib_unordered_map_try_emplace`	201411L	`<unordered_map>`
`__cpp_lib_unreachable`	202202L	`<utility>`	Yes
`__cpp_lib_unwrap_ref`	201811L	`<type_traits>`	Yes
`__cpp_lib_variant`	202306L	`<variant>`
`__cpp_lib_void_t`	201411L	`<type_traits>`	Yes
Total number of macros: 239

Notes

Each value in "Value" column follows the pattern: "yyyymmL", where "yyyy" is a year, and "mm" is a month when the corresponding feature-set was accepted for standardization. Some values where increased since the time of their introduction, if capabilities of given feature where extended. The table above contains only the most recent values (that is, taken from the latest C++ language draft standard). A full set of values, including the initial and intermediate ones, can be found in this table.

Compiler support
Freestanding and hosted
Language
Standard library
Standard library headers
Named requirements
Feature test macros (C++20)
Language support library
Concepts library (C++20)
Metaprogramming library (C++11)
Diagnostics library
General utilities library
Strings library
Containers library
Iterators library
Ranges library (C++20)
Algorithms library
Numerics library
Localizations library
Input/output library
Filesystem library (C++17)
Regular expressions library (C++11)
Concurrency support library (C++11)
Execution support library (C++26)
Technical specifications
Symbols index
External libraries

Feature testing (C++20)	A set of preprocessor macros to test the corresponding to C++ language and library features
C++ documentation for Headers required for a freestanding implementation
C++ documentation for Predefined Macro Symbols

Library feature-test macros (since C++20)

Notes

See also

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