minus.pass.cpp (1635B)
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> 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 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 }