1 //===----------------------------------------------------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9
10 // <tuple>
11
12 // template<class... Types>
13 // tuple<Types&&...> forward_as_tuple(Types&&... t);
14
15 // UNSUPPORTED: c++98, c++03
16
17 #include <tuple>
18 #include <type_traits>
19 #include <cassert>
20
21 template <class Tuple>
22 void
test0(const Tuple & t)23 test0(const Tuple& t)
24 {
25 static_assert(std::tuple_size<Tuple>::value == 0, "");
26 }
27
28 template <class Tuple>
29 void
test1a(const Tuple & t)30 test1a(const Tuple& t)
31 {
32 static_assert(std::tuple_size<Tuple>::value == 1, "");
33 static_assert(std::is_same<typename std::tuple_element<0, Tuple>::type, int&&>::value, "");
34 assert(std::get<0>(t) == 1);
35 }
36
37 template <class Tuple>
38 void
test1b(const Tuple & t)39 test1b(const Tuple& t)
40 {
41 static_assert(std::tuple_size<Tuple>::value == 1, "");
42 static_assert(std::is_same<typename std::tuple_element<0, Tuple>::type, int&>::value, "");
43 assert(std::get<0>(t) == 2);
44 }
45
46 template <class Tuple>
47 void
test2a(const Tuple & t)48 test2a(const Tuple& t)
49 {
50 static_assert(std::tuple_size<Tuple>::value == 2, "");
51 static_assert(std::is_same<typename std::tuple_element<0, Tuple>::type, double&>::value, "");
52 static_assert(std::is_same<typename std::tuple_element<1, Tuple>::type, char&>::value, "");
53 assert(std::get<0>(t) == 2.5);
54 assert(std::get<1>(t) == 'a');
55 }
56
57 #if _LIBCPP_STD_VER > 11
58 template <class Tuple>
59 constexpr int
test3(const Tuple & t)60 test3(const Tuple& t)
61 {
62 return std::tuple_size<Tuple>::value;
63 }
64 #endif
65
main()66 int main()
67 {
68 {
69 test0(std::forward_as_tuple());
70 }
71 {
72 test1a(std::forward_as_tuple(1));
73 }
74 {
75 int i = 2;
76 test1b(std::forward_as_tuple(i));
77 }
78 {
79 double i = 2.5;
80 char c = 'a';
81 test2a(std::forward_as_tuple(i, c));
82 #if _LIBCPP_STD_VER > 11
83 static_assert ( test3 (std::forward_as_tuple(i, c)) == 2, "" );
84 #endif
85 }
86 }
87