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- //
- // Copyright 2019 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.
- //
- // -----------------------------------------------------------------------------
- // File: declare.h
- // -----------------------------------------------------------------------------
- //
- // This file defines the ABSL_DECLARE_FLAG macro, allowing you to declare an
- // `absl::Flag` for use within a translation unit. You should place this
- // declaration within the header file associated with the .cc file that defines
- // and owns the `Flag`.
- #ifndef ABSL_FLAGS_DECLARE_H_
- #define ABSL_FLAGS_DECLARE_H_
- #include "absl/base/config.h"
- namespace absl {
- ABSL_NAMESPACE_BEGIN
- namespace flags_internal {
- // absl::Flag<T> represents a flag of type 'T' created by ABSL_FLAG.
- template <typename T>
- class Flag;
- } // namespace flags_internal
- // Flag
- //
- // Forward declaration of the `absl::Flag` type for use in defining the macro.
- #if defined(_MSC_VER) && !defined(__clang__)
- template <typename T>
- class Flag;
- #else
- template <typename T>
- using Flag = flags_internal::Flag<T>;
- #endif
- ABSL_NAMESPACE_END
- } // namespace absl
- // ABSL_DECLARE_FLAG()
- //
- // This macro is a convenience for declaring use of an `absl::Flag` within a
- // translation unit. This macro should be used within a header file to
- // declare usage of the flag within any .cc file including that header file.
- //
- // The ABSL_DECLARE_FLAG(type, name) macro expands to:
- //
- // extern absl::Flag<type> FLAGS_name;
- #define ABSL_DECLARE_FLAG(type, name) extern ::absl::Flag<type> FLAGS_##name
- #endif // ABSL_FLAGS_DECLARE_H_
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