bad_variant_access.h
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1 // Copyright 2018 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 // bad_variant_access.h
17 // -----------------------------------------------------------------------------
18 //
19 // This header file defines the `absl::bad_variant_access` type.
20 
21 #ifndef ABSL_TYPES_BAD_VARIANT_ACCESS_H_
22 #define ABSL_TYPES_BAD_VARIANT_ACCESS_H_
23 
24 #include <stdexcept>
25 
26 #include "absl/base/config.h"
27 
28 #ifdef ABSL_HAVE_STD_VARIANT
29 
30 #include <variant>
31 
32 namespace absl {
33 using std::bad_variant_access;
34 } // namespace absl
35 
36 #else // ABSL_HAVE_STD_VARIANT
37 
38 namespace absl {
39 
40 // -----------------------------------------------------------------------------
41 // bad_variant_access
42 // -----------------------------------------------------------------------------
43 //
44 // An `absl::bad_variant_access` type is an exception type that is thrown in
45 // the following cases:
46 //
47 // * Calling `absl::get(absl::variant) with an index or type that does not
48 // match the currently selected alternative type
49 // * Calling `absl::visit on an `absl::variant` that is in the
50 // `variant::valueless_by_exception` state.
51 //
52 // Example:
53 //
54 // absl::variant<int, std::string> v;
55 // v = 1;
56 // try {
57 // absl::get<std::string>(v);
58 // } catch(const absl::bad_variant_access& e) {
59 // std::cout << "Bad variant access: " << e.what() << '\n';
60 // }
61 class bad_variant_access : public std::exception {
62  public:
63  bad_variant_access() noexcept = default;
64  ~bad_variant_access() override;
65  const char* what() const noexcept override;
66 };
67 
68 namespace variant_internal {
69 
70 [[noreturn]] void ThrowBadVariantAccess();
71 [[noreturn]] void Rethrow();
72 
73 } // namespace variant_internal
74 } // namespace absl
75 
76 #endif // ABSL_HAVE_STD_VARIANT
77 
78 #endif // ABSL_TYPES_BAD_VARIANT_ACCESS_H_
~bad_variant_access() override
Definition: algorithm.h:29
const char * what() const noexceptoverride
bad_variant_access() noexcept=default


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autogenerated on Tue Jun 18 2019 19:44:35