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// <optional> 1101afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant 1201afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant// A program that necessitates the instantiation of template optional for 1301afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant// (possibly cv-qualified) null_opt_t is ill-formed. 1401afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant 150cdbe6048173c1f05628dbc85430acf191a3e173Marshall Clow#include <experimental/optional> 1601afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant 1701afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnantint main() 1801afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant{ 1901afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant#if _LIBCPP_STD_VER > 11 200cdbe6048173c1f05628dbc85430acf191a3e173Marshall Clow using std::experimental::optional; 210cdbe6048173c1f05628dbc85430acf191a3e173Marshall Clow using std::experimental::nullopt_t; 220cdbe6048173c1f05628dbc85430acf191a3e173Marshall Clow using std::experimental::nullopt; 230cdbe6048173c1f05628dbc85430acf191a3e173Marshall Clow 240cdbe6048173c1f05628dbc85430acf191a3e173Marshall Clow optional<nullopt_t> opt; 2501afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant#else 2601afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant#error 2701afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant#endif // _LIBCPP_STD_VER > 11 2801afa5c6e407e985d9643707d7b7ab1384bd9317Howard Hinnant} 29