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 10 11 // <optional> 12 13 // template <class T> constexpr bool operator<(const optional<T>& x, nullopt_t) noexcept; 14 // template <class T> constexpr bool operator<(nullopt_t, const optional<T>& x) noexcept; 15 16 #include <experimental/optional> 17 18 int main() 19 { 20 #if _LIBCPP_STD_VER > 11 21 using std::experimental::optional; 22 using std::experimental::nullopt_t; 23 using std::experimental::nullopt; 24 25 { 26 typedef int T; 27 typedef optional<T> O; 28 29 constexpr O o1; // disengaged 30 constexpr O o2{1}; // engaged 31 32 static_assert ( !(nullopt < o1), "" ); 33 static_assert ( nullopt < o2 , "" ); 34 static_assert ( !(o1 < nullopt), "" ); 35 static_assert ( !(o2 < nullopt), "" ); 36 37 static_assert (noexcept(nullopt < o1), ""); 38 static_assert (noexcept(o1 < nullopt), ""); 39 } 40 #endif 41 } 42
