1// { dg-options "-std=gnu++14" }
2
3// Copyright (C) 2013-2015 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library.  This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14// GNU General Public License for more details.
15
16// You should have received a copy of the GNU General Public License along
17// with this library; see the file COPYING3.  If not see
18// <http://www.gnu.org/licenses/>.
19
20// 20.2.3 exchange [utility.exchange]
21
22#include <utility>
23#include <type_traits>
24#include <testsuite_hooks.h>
25
26void
27test01()
28{
29  const unsigned val = 4;
30  int i = 1;
31  auto prev = std::exchange(i, val);
32  static_assert( std::is_same<decltype(prev), int>::value, "return type" );
33  VERIFY( i == 4 );
34  VERIFY( prev == 1 );
35  prev = std::exchange(i, 3);
36  VERIFY( i == 3 );
37  VERIFY( prev == 4 );
38}
39
40// Default construction from empty braces
41void
42test02()
43{
44  bool test __attribute__((unused)) = true;
45
46  struct DefaultConstructible
47  {
48    DefaultConstructible(int i = 0) : value(i) { }
49    int value;
50  };
51
52  DefaultConstructible x = 1;
53  auto old = std::exchange(x, {});
54  VERIFY( x.value == 0 );
55  VERIFY( old.value == 1 );
56}
57
58int f(int) { return 0; }
59
60double f(double) { return 0; }
61
62// Deduce type of overloaded function
63void
64test03()
65{
66  bool test __attribute__((unused)) = true;
67
68  int (*fp)(int);
69  std::exchange(fp, &f);
70  VERIFY( fp != nullptr );
71}
72
73void test04()
74{
75  struct From { };
76  struct To {
77    int value = 0;
78    To() = default;
79    To(const To&) = default;
80    To(const From&) = delete;
81    To& operator=(const From&) { value = 1; return *this; }
82    To& operator=(From&&) { value = 2; return *this; }
83  };
84
85  To t;
86  From f;
87
88  auto prev = std::exchange(t, f);
89  VERIFY( t.value == 1 );
90  VERIFY( prev.value == 0 );
91
92  prev = std::exchange(t, From{});
93  VERIFY( t.value == 2 );
94  VERIFY( prev.value == 1 );
95}
96
97int
98main()
99{
100  test01();
101  test02();
102  test03();
103  test04();
104  return 0;
105}
106