Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. — Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

This is the documentation for a development version of boost.

boost/json/detail/charconv/detail/fast_float/constexpr_feature_detect.hpp

// Copyright 2020-2023 Daniel Lemire
// Copyright 2023 Matt Borland
// Distributed under the Boost Software License, Version 1.0.
// https://www.boost.org/LICENSE_1_0.txt
//
// Derivative of: https://github.com/fastfloat/fast_float

#ifndef BOOST_JSON_DETAIL_CHARCONV_DETAIL_FASTFLOAT_CONSTEXPR_FEATURE_DETECT_HPP
#define BOOST_JSON_DETAIL_CHARCONV_DETAIL_FASTFLOAT_CONSTEXPR_FEATURE_DETECT_HPP

#ifdef __has_include
#if __has_include(<version>)
#include <version>
#endif
#endif

#if defined(__cpp_lib_bit_cast) && __cpp_lib_bit_cast >= 201806L
# define BOOST_JSON_HAS_BIT_CAST
#endif

#if defined(__cpp_lib_is_constant_evaluated) && __cpp_lib_is_constant_evaluated >= 201811L
# define BOOST_JSON_HAS_IS_CONSTANT_EVALUATED
#endif

// Testing for relevant C++20 constexpr library features
#if defined(BOOST_JSON_HAS_IS_CONSTANT_EVALUATED) \
    && defined(BOOST_JSON_HAS_BIT_CAST) \
    && __cpp_lib_constexpr_algorithms >= 201806L /*For std::copy and std::fill*/
#define BOOST_JSON_FASTFLOAT_CONSTEXPR20 constexpr
#else
#define BOOST_JSON_FASTFLOAT_CONSTEXPR20
#endif

#endif // BOOST_JSON_DETAIL_CHARCONV_FASTFLOAT_CONSTEXPR_FEATURE_DETECT_HPP