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 // UNSUPPORTED: c++03, c++11, c++14, c++17
9 
10 // <span>
11 
12 // [[nodiscard]] constexpr bool empty() const noexcept;
13 //
14 
15 
16 #include <span>
17 #include <cassert>
18 #include <string>
19 
20 #include "test_macros.h"
21 
22 struct A{};
23 constexpr int iArr1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9};
24           int iArr2[] = {10, 11, 12, 13, 14, 15, 16, 17, 18, 19};
25 
26 int main(int, char**)
27 {
28     static_assert( noexcept(std::span<int>   ().empty()), "");
29     static_assert( noexcept(std::span<int, 0>().empty()), "");
30 
31 
32     static_assert( std::span<int>().empty(),            "");
33     static_assert( std::span<long>().empty(),           "");
34     static_assert( std::span<double>().empty(),         "");
35     static_assert( std::span<A>().empty(),              "");
36     static_assert( std::span<std::string>().empty(),    "");
37 
38     static_assert( std::span<int, 0>().empty(),         "");
39     static_assert( std::span<long, 0>().empty(),        "");
40     static_assert( std::span<double, 0>().empty(),      "");
41     static_assert( std::span<A, 0>().empty(),           "");
42     static_assert( std::span<std::string, 0>().empty(), "");
43 
44     static_assert(!std::span<const int>(iArr1, 1).empty(), "");
45     static_assert(!std::span<const int>(iArr1, 2).empty(), "");
46     static_assert(!std::span<const int>(iArr1, 3).empty(), "");
47     static_assert(!std::span<const int>(iArr1, 4).empty(), "");
48     static_assert(!std::span<const int>(iArr1, 5).empty(), "");
49 
50     assert( (std::span<int>().empty()           ));
51     assert( (std::span<long>().empty()          ));
52     assert( (std::span<double>().empty()        ));
53     assert( (std::span<A>().empty()             ));
54     assert( (std::span<std::string>().empty()   ));
55 
56     assert( (std::span<int, 0>().empty()        ));
57     assert( (std::span<long, 0>().empty()       ));
58     assert( (std::span<double, 0>().empty()     ));
59     assert( (std::span<A, 0>().empty()          ));
60     assert( (std::span<std::string, 0>().empty()));
61 
62     assert(!(std::span<int, 1>(iArr2, 1).empty()));
63     assert(!(std::span<int, 2>(iArr2, 2).empty()));
64     assert(!(std::span<int, 3>(iArr2, 3).empty()));
65     assert(!(std::span<int, 4>(iArr2, 4).empty()));
66     assert(!(std::span<int, 5>(iArr2, 5).empty()));
67 
68     std::string s;
69     assert( ((std::span<std::string>(&s, (std::size_t) 0)).empty()));
70     assert(!((std::span<std::string>(&s, 1).empty())));
71 
72   return 0;
73 }
74