101afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant//===----------------------------------------------------------------------===// 201afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant// 301afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant// The LLVM Compiler Infrastructure 401afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant// 501afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant// This file is dual licensed under the MIT and the University of Illinois Open 601afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant// Source Licenses. See LICENSE.TXT for details. 701afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant// 801afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant//===----------------------------------------------------------------------===// 901afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant 1001afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant 1101afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant// <optional> 1201afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant 1306086258d3d8c48a916ec51c33e1ad8f46821b81Dan Albert// template <class T> constexpr bool operator!=(const optional<T>& x, nullopt_t) noexcept; 1406086258d3d8c48a916ec51c33e1ad8f46821b81Dan Albert// template <class T> constexpr bool operator!=(nullopt_t, const optional<T>& x) noexcept; 1501afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant 160cdbe6048173c1f05628dbc85430acf191a3e173Marshall Clow#include <experimental/optional> 1701afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant 1801afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnantint main() 1901afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant{ 2001afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant#if _LIBCPP_STD_VER > 11 217112dae6acac544a0271a85d95342c583441e2d1Dan Albert using std::experimental::optional; 227112dae6acac544a0271a85d95342c583441e2d1Dan Albert using std::experimental::nullopt_t; 237112dae6acac544a0271a85d95342c583441e2d1Dan Albert using std::experimental::nullopt; 240cdbe6048173c1f05628dbc85430acf191a3e173Marshall Clow 2501afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant { 2601afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant typedef int T; 270cdbe6048173c1f05628dbc85430acf191a3e173Marshall Clow typedef optional<T> O; 2801afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant 2901afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant constexpr O o1; // disengaged 3001afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant constexpr O o2{1}; // engaged 3101afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant 3206086258d3d8c48a916ec51c33e1ad8f46821b81Dan Albert static_assert ( !(nullopt != o1), "" ); 3306086258d3d8c48a916ec51c33e1ad8f46821b81Dan Albert static_assert ( (nullopt != o2), "" ); 3406086258d3d8c48a916ec51c33e1ad8f46821b81Dan Albert static_assert ( !(o1 != nullopt), "" ); 3506086258d3d8c48a916ec51c33e1ad8f46821b81Dan Albert static_assert ( (o2 != nullopt), "" ); 3601afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant 3706086258d3d8c48a916ec51c33e1ad8f46821b81Dan Albert static_assert (noexcept(nullopt != o1), ""); 3806086258d3d8c48a916ec51c33e1ad8f46821b81Dan Albert static_assert (noexcept(o1 != nullopt), ""); 3901afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant } 4001afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant#endif 4101afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant} 42