| // Copyright 2020 The Pigweed Authors |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); you may not |
| // use this file except in compliance with the License. You may obtain a copy of |
| // the License at |
| // |
| // https://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
| // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the |
| // License for the specific language governing permissions and limitations under |
| // the License. |
| |
| // Macros for using C++ features in older standards. |
| #pragma once |
| |
| // Mark functions as constexpr if C++20 or newer |
| #if __cplusplus >= 202002L |
| #define PW_CONSTEXPR_CPP20 constexpr |
| #else |
| #define PW_CONSTEXPR_CPP20 |
| #endif // __cpp_constexpr >= 201304L |
| |
| // Mark functions as consteval if supported. |
| #if defined(__cpp_consteval) && __cpp_consteval >= 201811L |
| #define PW_CONSTEVAL consteval |
| #else |
| #define PW_CONSTEVAL constexpr |
| #endif // __cpp_consteval >= 201811L |
| |
| // Mark functions as constinit if supported by the compiler. |
| #if defined(__cpp_constinit) && __cpp_constinit >= 201907L |
| #define PW_CONSTINIT constinit |
| #elif defined(__clang__) |
| #define PW_CONSTINIT [[clang::require_constant_initialization]] |
| #elif defined(__GNUC__) && __GNUC__ >= 13 |
| #define PW_CONSTINIT __constinit |
| #else |
| #define PW_CONSTINIT |
| #endif // __cpp_constinit |
| |
| // nodiscard with a string literal is only available in later versions (~C++20). |
| #if __cplusplus >= 202002L |
| #define PW_NODISCARD_STR(str) [[nodiscard(str)]] |
| #else |
| #define PW_NODISCARD_STR(str) [[nodiscard]] |
| #endif |
