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9687a8ea75
I.e. for a type `Example`, if ``` std::ostream& operator<<(std::ostream&, const Example&); ``` is declared, `absl::HasOstreamOperator<Example>::value` is `true`. PiperOrigin-RevId: 574637891 Change-Id: I123d8f35a6e3ea894745133f7d81b1610fb475d5
43 lines
1.3 KiB
C++
43 lines
1.3 KiB
C++
// Copyright 2023 The Abseil Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#ifndef ABSL_STRINGS_HAS_OSTREAM_OPERATOR_H_
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#define ABSL_STRINGS_HAS_OSTREAM_OPERATOR_H_
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#include <ostream>
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#include <type_traits>
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#include <utility>
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#include "absl/base/config.h"
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namespace absl {
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ABSL_NAMESPACE_BEGIN
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// Detects if type `T` supports streaming to `std::ostream`s with `operator<<`.
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template <typename T, typename = void>
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struct HasOstreamOperator : std::false_type {};
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template <typename T>
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struct HasOstreamOperator<
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T, std::enable_if_t<std::is_same<
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std::ostream&, decltype(std::declval<std::ostream&>()
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<< std::declval<const T&>())>::value>>
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: std::true_type {};
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ABSL_NAMESPACE_END
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} // namespace absl
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#endif // ABSL_STRINGS_HAS_OSTREAM_OPERATOR_H_
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