1 // Copyright 2022 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 // File: log/internal/voidify.h 17 // ----------------------------------------------------------------------------- 18 // 19 // This class is used to explicitly ignore values in the conditional logging 20 // macros. This avoids compiler warnings like "value computed is not used" and 21 // "statement has no effect". 22 23 #ifndef ABSL_LOG_INTERNAL_VOIDIFY_H_ 24 #define ABSL_LOG_INTERNAL_VOIDIFY_H_ 25 26 #include "absl/base/config.h" 27 28 namespace absl { 29 ABSL_NAMESPACE_BEGIN 30 namespace log_internal { 31 32 class Voidify final { 33 public: 34 // This has to be an operator with a precedence lower than << but higher than 35 // ?: 36 template <typename T> 37 void operator&&(const T&) const&& {} 38 }; 39 40 } // namespace log_internal 41 ABSL_NAMESPACE_END 42 } // namespace absl 43 44 #endif // ABSL_LOG_INTERNAL_VOIDIFY_H_ 45