libcxx/test/std/time/time.cal/time.cal.year/time.cal.year.nonmembers/minus.pass.cpp

   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 year;
  12
  13 // constexpr year operator-(const year& x, const years& y) noexcept;
  14 //   Returns: x + -y.
  15 //
  16 // constexpr years operator-(const year& x, const year& y) noexcept;
  17 //   Returns: If x.ok() == true and y.ok() == true, returns a value m in the range
  18 //   [years{0}, years{11}] satisfying y + m == x.
  19 //   Otherwise the value returned is unspecified.
  20 //   [Example: January - February == years{11}. -end example]
  21
  22 #include <chrono>
  23 #include <type_traits>
  24 #include <cassert>
  25
  26 #include "test_macros.h"
  27
  28 using year  = std::chrono::year;
  29 using years = std::chrono::years;
  30
  31 constexpr bool test() {
  32   year y{1223};
  33   for (int i = 1100; i <= 1110; ++i) {
  34     year y1   = y - years{i};
  35     years ys1 = y - year{i};
  36     assert(static_cast<int>(y1) == 1223 - i);
  37     assert(ys1.count() == 1223 - i);
  38   }
  39
  40   return true;
  41 }
  42
  43 int main(int, char**) {
  44   ASSERT_NOEXCEPT(std::declval<year>() - std::declval<years>());
  45   ASSERT_SAME_TYPE(year, decltype(std::declval<year>() - std::declval<years>()));
  46
  47   ASSERT_NOEXCEPT(std::declval<year>() - std::declval<year>());
  48   ASSERT_SAME_TYPE(years, decltype(std::declval<year>() - std::declval<year>()));
  49
  50   test();
  51   static_assert(test());
  52
  53   return 0;
  54 }