// // cpp11/can_prefer_member_require.cpp // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ // // Copyright (c) 2003-2024 Christopher M. Kohlhoff (chris at kohlhoff dot com) // // Distributed under the Boost Software License, Version 1.0. (See accompanying // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // #include "asio/prefer.hpp" #include template struct prop { static constexpr bool is_preferable = true; }; template struct object { template constexpr object require(prop) const { return object(); } }; namespace asio { template struct is_applicable_property, prop > { static constexpr bool value = true; }; } // namespace asio int main() { static_assert(asio::can_prefer, prop<2>>::value, ""); static_assert(asio::can_prefer, prop<2>, prop<3>>::value, ""); static_assert(asio::can_prefer, prop<2>, prop<3>, prop<4>>::value, ""); static_assert(asio::can_prefer, prop<2>>::value, ""); static_assert(asio::can_prefer, prop<2>, prop<3>>::value, ""); static_assert(asio::can_prefer, prop<2>, prop<3>, prop<4>>::value, ""); }