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 // type_traits
11
12 // is_empty
13
14 // T is a non-union class type with:
15 // no non-static data members,
16 // no unnamed bit-fields of non-zero length,
17 // no virtual member functions,
18 // no virtual base classes,
19 // and no base class B for which is_empty_v<B> is false.
20
21
22 #include <type_traits>
23 #include "test_macros.h"
24
25 template <class T>
test_is_empty()26 void test_is_empty()
27 {
28 static_assert( std::is_empty<T>::value, "");
29 static_assert( std::is_empty<const T>::value, "");
30 static_assert( std::is_empty<volatile T>::value, "");
31 static_assert( std::is_empty<const volatile T>::value, "");
32 #if TEST_STD_VER > 14
33 static_assert( std::is_empty_v<T>, "");
34 static_assert( std::is_empty_v<const T>, "");
35 static_assert( std::is_empty_v<volatile T>, "");
36 static_assert( std::is_empty_v<const volatile T>, "");
37 #endif
38 }
39
40 template <class T>
test_is_not_empty()41 void test_is_not_empty()
42 {
43 static_assert(!std::is_empty<T>::value, "");
44 static_assert(!std::is_empty<const T>::value, "");
45 static_assert(!std::is_empty<volatile T>::value, "");
46 static_assert(!std::is_empty<const volatile T>::value, "");
47 #if TEST_STD_VER > 14
48 static_assert(!std::is_empty_v<T>, "");
49 static_assert(!std::is_empty_v<const T>, "");
50 static_assert(!std::is_empty_v<volatile T>, "");
51 static_assert(!std::is_empty_v<const volatile T>, "");
52 #endif
53 }
54
55 class Empty {};
56 struct NotEmpty { int foo; };
57
58 class VirtualFn
59 {
60 virtual ~VirtualFn();
61 };
62
63 union Union {};
64
65 struct EmptyBase : public Empty {};
66 struct VirtualBase : virtual Empty {};
67 struct NotEmptyBase : public NotEmpty {};
68
69 struct StaticMember { static int foo; };
70 struct NonStaticMember { int foo; };
71
72 struct bit_zero
73 {
74 int : 0;
75 };
76
77 struct bit_one
78 {
79 int : 1;
80 };
81
main()82 int main()
83 {
84 test_is_not_empty<void>();
85 test_is_not_empty<int&>();
86 test_is_not_empty<int>();
87 test_is_not_empty<double>();
88 test_is_not_empty<int*>();
89 test_is_not_empty<const int*>();
90 test_is_not_empty<char[3]>();
91 test_is_not_empty<char[]>();
92 test_is_not_empty<Union>();
93 test_is_not_empty<NotEmpty>();
94 test_is_not_empty<VirtualFn>();
95 test_is_not_empty<VirtualBase>();
96 test_is_not_empty<NotEmptyBase>();
97 test_is_not_empty<NonStaticMember>();
98 // test_is_not_empty<bit_one>();
99
100 test_is_empty<Empty>();
101 test_is_empty<EmptyBase>();
102 test_is_empty<StaticMember>();
103 test_is_empty<bit_zero>();
104 }
105