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 // <array>
10 
11 // T *data();
12 
13 #include <array>
14 #include <cassert>
15 #include <cstddef>       // for std::max_align_t
16 
17 #include "test_macros.h"
18 
19 // std::array is explicitly allowed to be initialized with A a = { init-list };.
20 // Disable the missing braces warning for this reason.
21 #include "disable_missing_braces_warning.h"
22 
23 struct NoDefault {
24     TEST_CONSTEXPR NoDefault(int) { }
25 };
26 
27 #if TEST_STD_VER < 11
28 struct natural_alignment {
29     long t1;
30     long long t2;
31     double t3;
32     long double t4;
33 };
34 #endif
35 
36 TEST_CONSTEXPR_CXX17 bool tests()
37 {
38     {
39         typedef double T;
40         typedef std::array<T, 3> C;
41         C c = {1, 2, 3.5};
42         T* p = c.data();
43         assert(p[0] == 1);
44         assert(p[1] == 2);
45         assert(p[2] == 3.5);
46     }
47     {
48         typedef double T;
49         typedef std::array<T, 0> C;
50         C c = {};
51         T* p = c.data();
52         (void)p;
53     }
54     {
55         typedef double T;
56         typedef std::array<const T, 0> C;
57         C c = {{}};
58         const T* p = c.data();
59         (void)p;
60         static_assert((std::is_same<decltype(c.data()), const T*>::value), "");
61     }
62     {
63         typedef NoDefault T;
64         typedef std::array<T, 0> C;
65         C c = {};
66         T* p = c.data();
67         (void)p;
68     }
69     {
70         std::array<int, 5> c = {0, 1, 2, 3, 4};
71         assert(c.data() == &c[0]);
72         assert(*c.data() == c[0]);
73     }
74 
75     return true;
76 }
77 
78 int main(int, char**)
79 {
80     tests();
81 #if TEST_STD_VER >= 17
82     static_assert(tests(), "");
83 #endif
84 
85     // Test the alignment of data()
86     {
87 #if TEST_STD_VER < 11
88         typedef natural_alignment T;
89 #else
90         typedef std::max_align_t T;
91 #endif
92         typedef std::array<T, 0> C;
93         const C c = {};
94         const T* p = c.data();
95         std::uintptr_t pint = reinterpret_cast<std::uintptr_t>(p);
96         assert(pint % TEST_ALIGNOF(T) == 0);
97     }
98     return 0;
99 }
100