| //===----------------------------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // UNSUPPORTED: c++98, c++03, c++11, c++14, c++17 |
| |
| // <chrono> |
| // class month; |
| |
| // constexpr month operator-(const month& x, const months& y) noexcept; |
| // Returns: x + -y. |
| // |
| // constexpr months operator-(const month& x, const month& y) noexcept; |
| // Returns: If x.ok() == true and y.ok() == true, returns a value m in the range |
| // [months{0}, months{11}] satisfying y + m == x. |
| // Otherwise the value returned is unspecified. |
| // [Example: January - February == months{11}. —end example] |
| |
| #include <chrono> |
| #include <type_traits> |
| #include <cassert> |
| |
| #include "test_macros.h" |
| |
| template <typename M, typename Ms> |
| constexpr bool testConstexpr() |
| { |
| { |
| M m{5}; |
| Ms offset{3}; |
| if (m - offset != M{2}) return false; |
| if (m - M{2} != offset) return false; |
| } |
| |
| // Check the example |
| if (M{1} - M{2} != Ms{11}) return false; |
| return true; |
| } |
| |
| int main(int, char**) |
| { |
| using month = std::chrono::month; |
| using months = std::chrono::months; |
| |
| ASSERT_NOEXCEPT(std::declval<month>() - std::declval<months>()); |
| ASSERT_NOEXCEPT(std::declval<month>() - std::declval<month>()); |
| |
| ASSERT_SAME_TYPE(month , decltype(std::declval<month>() - std::declval<months>())); |
| ASSERT_SAME_TYPE(months, decltype(std::declval<month>() - std::declval<month> ())); |
| |
| static_assert(testConstexpr<month, months>(), ""); |
| |
| month m{6}; |
| for (unsigned i = 1; i <= 12; ++i) |
| { |
| month m1 = m - months{i}; |
| // months off = m - month {i}; |
| int exp = 6 - i; |
| if (exp < 1) |
| exp += 12; |
| assert(static_cast<unsigned>(m1) == static_cast<unsigned>(exp)); |
| // assert(off.count() == static_cast<unsigned>(exp)); |
| } |
| |
| return 0; |
| } |