identity.h (1141B)
1 // Copyright 2017 The Abseil Authors. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 // 15 16 #ifndef ABSL_BASE_INTERNAL_IDENTITY_H_ 17 #define ABSL_BASE_INTERNAL_IDENTITY_H_ 18 19 #include "absl/base/config.h" 20 21 namespace absl { 22 ABSL_NAMESPACE_BEGIN 23 namespace internal { 24 25 // This is a back-fill of C++20's `std::type_identity`. 26 template <typename T> 27 struct type_identity { 28 typedef T type; 29 }; 30 31 // This is a back-fill of C++20's `std::type_identity_t`. 32 template <typename T> 33 using type_identity_t = typename type_identity<T>::type; 34 35 } // namespace internal 36 ABSL_NAMESPACE_END 37 } // namespace absl 38 39 #endif // ABSL_BASE_INTERNAL_IDENTITY_H_