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#ifndef RUBY3_ATTR_CONSTEXPR_H /*-*-C++-*-vi:se ft=cpp:*/
#define RUBY3_ATTR_CONSTEXPR_H
/**
* @file
* @author Ruby developers <ruby-core@ruby-lang.org>
* @copyright This file is a part of the programming language Ruby.
* Permission is hereby granted, to either redistribute and/or
* modify this file, provided that the conditions mentioned in the
* file COPYING are met. Consult the file for details.
* @warning Symbols prefixed with either `RUBY3` or `ruby3` are
* implementation details. Don't take them as canon. They could
* rapidly appear then vanish. The name (path) of this header file
* is also an implementation detail. Do not expect it to persist
* at the place it is now. Developers are free to move it anywhere
* anytime at will.
* @note To ruby-core: remember that this header can be possibly
* recursively included from extension libraries written in C++.
* Do not expect for instance `__VA_ARGS__` is always available.
* We assume C99 for ruby itself but we don't assume languages of
* extension libraries. They could be written in C++98.
* @brief #RUBY3_ATTR_CONSTEXPR.
*/
#include "ruby/3/has/feature.h"
#include "ruby/3/compiler_is.h"
#include "ruby/3/token_paste.h"
/** @cond INTERNAL_MACRO */
#if ! defined(__cplusplus)
# /* Makes no sense. */
# define RUBY3_HAS_ATTR_CONSTEXPR_CXX11 0
# define RUBY3_HAS_ATTR_CONSTEXPR_CXX14 0
#elif defined(__cpp_constexpr)
# /* https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations */
# define RUBY3_HAS_ATTR_CONSTEXPR_CXX11 (__cpp_constexpr >= 200704L)
# define RUBY3_HAS_ATTR_CONSTEXPR_CXX14 (__cpp_constexpr >= 201304L)
#elif RUBY3_COMPILER_SINCE(MSVC, 19, 0, 0)
# define RUBY3_HAS_ATTR_CONSTEXPR_CXX11 RUBY3_COMPILER_SINCE(MSVC, 19, 00, 00)
# define RUBY3_HAS_ATTR_CONSTEXPR_CXX14 RUBY3_COMPILER_SINCE(MSVC, 19, 11, 00)
#elif RUBY3_COMPILER_SINCE(SunPro, 5, 13, 0)
# define RUBY3_HAS_ATTR_CONSTEXPR_CXX11 (__cplusplus >= 201103L)
# define RUBY3_HAS_ATTR_CONSTEXPR_CXX14 (__cplusplus >= 201402L)
#elif RUBY3_COMPILER_SINCE(GCC, 4, 9, 0)
# define RUBY3_HAS_ATTR_CONSTEXPR_CXX11 (__cplusplus >= 201103L)
# define RUBY3_HAS_ATTR_CONSTEXPR_CXX14 (__cplusplus >= 201402L)
#elif RUBY3_HAS_FEATURE(cxx_relaxed_constexpr)
# define RUBY3_HAS_ATTR_CONSTEXPR_CXX11 1
# define RUBY3_HAS_ATTR_CONSTEXPR_CXX14 1
#elif RUBY3_HAS_FEATURE(cxx_constexpr)
# define RUBY3_HAS_ATTR_CONSTEXPR_CXX11 1
# define RUBY3_HAS_ATTR_CONSTEXPR_CXX14 0
#else
# /* :FIXME: icpc must have constexpr but don't know how to detect. */
# define RUBY3_HAS_ATTR_CONSTEXPR_CXX11 0
# define RUBY3_HAS_ATTR_CONSTEXPR_CXX14 0
#endif
/** @endcond */
/** Wraps (or simulates) C++11 `constexpr`. */
#if RUBY3_HAS_ATTR_CONSTEXPR_CXX14
# define RUBY3_ATTR_CONSTEXPR(_) constexpr
#elif RUBY3_HAS_ATTR_CONSTEXPR_CXX11
# define RUBY3_ATTR_CONSTEXPR(_) RUBY3_TOKEN_PASTE(RUBY3_ATTR_CONSTEXPR_, _)
# define RUBY3_ATTR_CONSTEXPR_CXX11 constexpr
# define RUBY3_ATTR_CONSTEXPR_CXX14 /* void */
#else
# define RUBY3_ATTR_CONSTEXPR(_) /* void */
#endif
/** Enables #RUBY3_ATTR_CONSTEXPR iff. #RUBY_NDEBUG. */
#if RUBY_NDEBUG
# define RUBY3_ATTR_CONSTEXPR_ON_NDEBUG(_) RUBY3_ATTR_CONSTEXPR(_)
#else
# define RUBY3_ATTR_CONSTEXPR_ON_NDEBUG(_) /* void */
#endif
#endif /* RUBY3_ATTR_CONSTEXPR_H */
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