| // Copyright 2018 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. |
| // |
| // ----------------------------------------------------------------------------- |
| // bad_variant_access.h |
| // ----------------------------------------------------------------------------- |
| // |
| // This header file defines the `absl::bad_variant_access` type. |
| |
| #ifndef ABSL_TYPES_BAD_VARIANT_ACCESS_H_ |
| #define ABSL_TYPES_BAD_VARIANT_ACCESS_H_ |
| |
| #include <stdexcept> |
| |
| #include "absl/base/config.h" |
| |
| #ifdef ABSL_USES_STD_VARIANT |
| |
| #include <variant> |
| |
| namespace absl { |
| ABSL_NAMESPACE_BEGIN |
| using std::bad_variant_access; |
| ABSL_NAMESPACE_END |
| } // namespace absl |
| |
| #else // ABSL_USES_STD_VARIANT |
| |
| namespace absl { |
| ABSL_NAMESPACE_BEGIN |
| |
| // ----------------------------------------------------------------------------- |
| // bad_variant_access |
| // ----------------------------------------------------------------------------- |
| // |
| // An `absl::bad_variant_access` type is an exception type that is thrown in |
| // the following cases: |
| // |
| // * Calling `absl::get(absl::variant) with an index or type that does not |
| // match the currently selected alternative type |
| // * Calling `absl::visit on an `absl::variant` that is in the |
| // `variant::valueless_by_exception` state. |
| // |
| // Example: |
| // |
| // absl::variant<int, std::string> v; |
| // v = 1; |
| // try { |
| // absl::get<std::string>(v); |
| // } catch(const absl::bad_variant_access& e) { |
| // std::cout << "Bad variant access: " << e.what() << '\n'; |
| // } |
| class bad_variant_access : public std::exception { |
| public: |
| bad_variant_access() noexcept = default; |
| ~bad_variant_access() override; |
| const char* what() const noexcept override; |
| }; |
| |
| namespace variant_internal { |
| |
| [[noreturn]] ABSL_DLL void ThrowBadVariantAccess(); |
| [[noreturn]] ABSL_DLL void Rethrow(); |
| |
| } // namespace variant_internal |
| ABSL_NAMESPACE_END |
| } // namespace absl |
| |
| #endif // ABSL_USES_STD_VARIANT |
| |
| #endif // ABSL_TYPES_BAD_VARIANT_ACCESS_H_ |