1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9// UNSUPPORTED: c++03, c++11, c++14
10
11// <variant>
12
13// template <class ...Types> class variant;
14
15// constexpr size_t index() const noexcept;
16
17#include <cassert>
18#include <string>
19#include <type_traits>
20#include <variant>
21
22#include "archetypes.h"
23#include "test_macros.h"
24#include "variant_test_helpers.h"
25
26
27int main(int, char**) {
28 {
29 using V = std::variant<int, long>;
30 constexpr V v;
31 static_assert(v.index() == 0, "");
32 }
33 {
34 using V = std::variant<int, long>;
35 V v;
36 assert(v.index() == 0);
37 }
38 {
39 using V = std::variant<int, long>;
40 constexpr V v(std::in_place_index<1>);
41 static_assert(v.index() == 1, "");
42 }
43 {
44 using V = std::variant<int, std::string>;
45 V v("abc");
46 assert(v.index() == 1);
47 v = 42;
48 assert(v.index() == 0);
49 }
50#ifndef TEST_HAS_NO_EXCEPTIONS
51 {
52 using V = std::variant<int, MakeEmptyT>;
53 V v;
54 assert(v.index() == 0);
55 makeEmpty(v);
56 assert(v.index() == std::variant_npos);
57 }
58#endif
59
60 return 0;
61}
62

source code of libcxx/test/std/utilities/variant/variant.variant/variant.status/index.pass.cpp