| // Copyright 2023 The Abseil 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. | |
| namespace absl { | |
| ABSL_NAMESPACE_BEGIN | |
| // Detects if type `T` supports streaming to `std::ostream`s with `operator<<`. | |
| template <typename T, typename = void> | |
| struct HasOstreamOperator : std::false_type {}; | |
| template <typename T> | |
| struct HasOstreamOperator< | |
| T, std::enable_if_t<std::is_same< | |
| std::ostream&, decltype(std::declval<std::ostream&>() | |
| << std::declval<const T&>())>::value>> | |
| : std::true_type {}; | |
| ABSL_NAMESPACE_END | |
| } // namespace absl | |