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
10
11// <utility>
12
13// template <class T1, class T2> struct pair
14
15// struct piecewise_construct_t { explicit piecewise_construct_t() = default; };
16// constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
17
18#include <utility>
19#include <tuple>
20#include <cassert>
21
22#include "test_macros.h"
23
24class A
25{
26 int i_;
27 char c_;
28public:
29 constexpr A(int i, char c) : i_(i), c_(c) {}
30 constexpr int get_i() const {return i_;}
31 constexpr char get_c() const {return c_;}
32};
33
34class B
35{
36 double d_;
37 unsigned u1_;
38 unsigned u2_;
39public:
40 constexpr explicit B(double d, unsigned u1, unsigned u2) : d_(d), u1_(u1), u2_(u2) {}
41 constexpr double get_d() const {return d_;}
42 constexpr unsigned get_u1() const {return u1_;}
43 constexpr unsigned get_u2() const {return u2_;}
44};
45
46TEST_CONSTEXPR_CXX20
47bool test()
48{
49 std::pair<A, B> p(std::piecewise_construct,
50 std::make_tuple(args: 4, args: 'a'),
51 std::make_tuple(args: 3.5, args: 6u, args: 2u));
52 assert(p.first.get_i() == 4);
53 assert(p.first.get_c() == 'a');
54 assert(p.second.get_d() == 3.5);
55 assert(p.second.get_u1() == 6u);
56 assert(p.second.get_u2() == 2u);
57
58 return true;
59}
60
61int main(int, char**)
62{
63 test();
64#if TEST_STD_VER >= 20
65 static_assert(test());
66#endif
67
68 return 0;
69}
70

source code of libcxx/test/std/utilities/utility/pairs/pair.piecewise/piecewise_construct.pass.cpp