.. _FeatureTestMacroTable:

==========================
Feature Test Macro Support
==========================

.. contents::
   :local:

Overview
========

This file documents the feature test macros currently supported by libc++.

.. _feature-status:

Status
======

.. table:: Current Status
     :name: feature-status-table
     :widths: auto

    ================================================= =================
    Macro Name                                        Value
    ================================================= =================
    **C++ 14**
    -------------------------------------------------------------------
    ``__cpp_lib_chrono_udls``                         ``201304L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_complex_udls``                        ``201309L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_exchange_function``                   ``201304L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_generic_associative_lookup``          ``201304L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_integer_sequence``                    ``201304L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_integral_constant_callable``          ``201304L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_is_final``                            ``201402L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_is_null_pointer``                     ``201309L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_make_reverse_iterator``               ``201402L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_make_unique``                         ``201304L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_null_iterators``                      ``201304L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_quoted_string_io``                    ``201304L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_result_of_sfinae``                    ``201210L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_robust_nonmodifying_seq_ops``         ``201304L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_shared_timed_mutex``                  ``201402L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_string_udls``                         ``201304L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_transformation_trait_aliases``        ``201304L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_transparent_operators``               ``201210L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_tuple_element_t``                     ``201402L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_tuples_by_type``                      ``201304L``
    ------------------------------------------------- -----------------
    **C++ 17**
    -------------------------------------------------------------------
    ``__cpp_lib_addressof_constexpr``                 ``201603L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_allocator_traits_is_always_equal``    ``201411L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_any``                                 ``201606L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_apply``                               ``201603L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_array_constexpr``                     ``201603L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_as_const``                            ``201510L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_atomic_is_always_lock_free``          ``201603L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_bool_constant``                       ``201505L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_boyer_moore_searcher``                *unimplemented*
    ------------------------------------------------- -----------------
    ``__cpp_lib_byte``                                ``201603L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_chrono``                              ``201611L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_clamp``                               ``201603L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_enable_shared_from_this``             ``201603L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_execution``                           *unimplemented*
    ------------------------------------------------- -----------------
    ``__cpp_lib_filesystem``                          ``201703L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_gcd_lcm``                             ``201606L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_hardware_interference_size``          *unimplemented*
    ------------------------------------------------- -----------------
    ``__cpp_lib_has_unique_object_representations``   ``201606L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_hypot``                               ``201603L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_incomplete_container_elements``       ``201505L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_invoke``                              ``201411L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_is_aggregate``                        ``201703L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_is_invocable``                        ``201703L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_is_swappable``                        ``201603L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_launder``                             ``201606L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_logical_traits``                      ``201510L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_make_from_tuple``                     ``201606L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_map_try_emplace``                     ``201411L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_math_special_functions``              *unimplemented*
    ------------------------------------------------- -----------------
    ``__cpp_lib_memory_resource``                     *unimplemented*
    ------------------------------------------------- -----------------
    ``__cpp_lib_node_extract``                        ``201606L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_nonmember_container_access``          ``201411L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_not_fn``                              ``201603L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_optional``                            ``201606L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_parallel_algorithm``                  *unimplemented*
    ------------------------------------------------- -----------------
    ``__cpp_lib_raw_memory_algorithms``               ``201606L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_sample``                              ``201603L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_scoped_lock``                         ``201703L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_shared_mutex``                        ``201505L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_shared_ptr_arrays``                   ``201611L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_shared_ptr_weak_type``                ``201606L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_string_view``                         ``201606L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_to_chars``                            *unimplemented*
    ------------------------------------------------- -----------------
    ``__cpp_lib_transparent_operators``               ``201510L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_type_trait_variable_templates``       ``201510L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_uncaught_exceptions``                 ``201411L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_unordered_map_try_emplace``           ``201411L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_variant``                             ``201606L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_void_t``                              ``201411L``
    ------------------------------------------------- -----------------
    **C++ 2a**
    -------------------------------------------------------------------
    ``__cpp_lib_array_constexpr``                     ``201811L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_atomic_flag_test``                    ``201907L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_atomic_float``                        *unimplemented*
    ------------------------------------------------- -----------------
    ``__cpp_lib_atomic_lock_free_type_aliases``       ``201907L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_atomic_ref``                          *unimplemented*
    ------------------------------------------------- -----------------
    ``__cpp_lib_atomic_shared_ptr``                   *unimplemented*
    ------------------------------------------------- -----------------
    ``__cpp_lib_atomic_value_initialization``         *unimplemented*
    ------------------------------------------------- -----------------
    ``__cpp_lib_atomic_wait``                         ``201907L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_bind_front``                          *unimplemented*
    ------------------------------------------------- -----------------
    ``__cpp_lib_bit_cast``                            *unimplemented*
    ------------------------------------------------- -----------------
    ``__cpp_lib_char8_t``                             ``201811L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_concepts``                            *unimplemented*
    ------------------------------------------------- -----------------
    ``__cpp_lib_constexpr_dynamic_alloc``             ``201907L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_constexpr_misc``                      *unimplemented*
    ------------------------------------------------- -----------------
    ``__cpp_lib_constexpr_numeric``                   ``201911L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_constexpr_swap_algorithms``           *unimplemented*
    ------------------------------------------------- -----------------
    ``__cpp_lib_constexpr_utility``                   ``201811L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_destroying_delete``                   ``201806L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_endian``                              ``201907L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_erase_if``                            ``202002L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_generic_unordered_lookup``            ``201811L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_int_pow2``                            ``202002L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_interpolate``                         ``201902L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_is_constant_evaluated``               ``201811L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_list_remove_return_type``             ``201806L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_math_constants``                      ``201907L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_ranges``                              *unimplemented*
    ------------------------------------------------- -----------------
    ``__cpp_lib_span``                                ``202002L``
    ------------------------------------------------- -----------------
    ``__cpp_lib_three_way_comparison``                *unimplemented*
    ------------------------------------------------- -----------------
    ``__cpp_lib_to_array``                            ``201907L``
    ================================================= =================