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 // UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
10
11 // <chrono>
12 // class day;
13
14 // constexpr day operator-(const day& x, const days& y) noexcept;
15 // Returns: x + -y.
16 //
17 // constexpr days operator-(const day& x, const day& y) noexcept;
18 // Returns: days{int(unsigned{x}) - int(unsigned{y}).
19
20
21 #include <chrono>
22 #include <type_traits>
23 #include <cassert>
24
25 #include "test_macros.h"
26
27 template <typename D, typename Ds>
testConstexpr()28 constexpr bool testConstexpr()
29 {
30 D d{23};
31 Ds offset{6};
32 if (d - offset != D{17}) return false;
33 if (d - D{17} != offset) return false;
34 return true;
35 }
36
main()37 int main()
38 {
39 using day = std::chrono::day;
40 using days = std::chrono::days;
41
42 ASSERT_NOEXCEPT(std::declval<day>() - std::declval<days>());
43 ASSERT_NOEXCEPT(std::declval<day>() - std::declval<day>());
44
45 ASSERT_SAME_TYPE(day, decltype(std::declval<day>() - std::declval<days>()));
46 ASSERT_SAME_TYPE(days, decltype(std::declval<day>() - std::declval<day>()));
47
48 static_assert(testConstexpr<day, days>(), "");
49
50 day dy{12};
51 for (unsigned i = 0; i <= 10; ++i)
52 {
53 day d1 = dy - days{i};
54 days off = dy - day {i};
55 assert(static_cast<unsigned>(d1) == 12 - i);
56 assert(off.count() == static_cast<int>(12 - i)); // days is signed
57 }
58 }
59