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 // <chrono>
11 // class day;
12
13 // constexpr day operator-(const day& x, const days& y) noexcept;
14 // Returns: x + -y.
15 //
16 // constexpr days operator-(const day& x, const day& y) noexcept;
17 // Returns: days{int(unsigned{x}) - int(unsigned{y}).
18
19
20 #include <chrono>
21 #include <type_traits>
22 #include <cassert>
23
24 #include "test_macros.h"
25
26 template <typename D, typename Ds>
testConstexpr()27 constexpr bool testConstexpr()
28 {
29 D d{23};
30 Ds offset{6};
31 if (d - offset != D{17}) return false;
32 if (d - D{17} != offset) return false;
33 return true;
34 }
35
main(int,char **)36 int main(int, char**)
37 {
38 using day = std::chrono::day;
39 using days = std::chrono::days;
40
41 ASSERT_NOEXCEPT(std::declval<day>() - std::declval<days>());
42 ASSERT_NOEXCEPT(std::declval<day>() - std::declval<day>());
43
44 ASSERT_SAME_TYPE(day, decltype(std::declval<day>() - std::declval<days>()));
45 ASSERT_SAME_TYPE(days, decltype(std::declval<day>() - std::declval<day>()));
46
47 static_assert(testConstexpr<day, days>(), "");
48
49 day dy{12};
50 for (unsigned i = 0; i <= 10; ++i)
51 {
52 day d1 = dy - days{i};
53 days off = dy - day {i};
54 assert(static_cast<unsigned>(d1) == 12 - i);
55 assert(off.count() == static_cast<int>(12 - i)); // days is signed
56 }
57
58 return 0;
59 }
60