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// <optional> 11 12// constexpr const T& optional<T>::value() const; 13 14#include <experimental/optional> 15#include <type_traits> 16#include <cassert> 17 18#if _LIBCPP_STD_VER > 11 19 20using std::experimental::optional; 21using std::experimental::in_place_t; 22using std::experimental::in_place; 23using std::experimental::bad_optional_access; 24 25struct X 26{ 27 X() = default; 28 X(const X&) = delete; 29 constexpr int test() const {return 3;} 30 int test() {return 4;} 31}; 32 33#endif // _LIBCPP_STD_VER > 11 34 35int main() 36{ 37#if _LIBCPP_STD_VER > 11 38 { 39 constexpr optional<X> opt(in_place); 40 static_assert(opt.value().test() == 3, ""); 41 } 42 { 43 const optional<X> opt(in_place); 44 assert(opt.value().test() == 3); 45 } 46 { 47 const optional<X> opt; 48 try 49 { 50 opt.value(); 51 assert(false); 52 } 53 catch (const bad_optional_access&) 54 { 55 } 56 } 57#endif // _LIBCPP_STD_VER > 11 58} 59