// // cpp14/can_require_free.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/require.hpp" #include template struct prop { template static constexpr bool is_applicable_property_v = true; static constexpr bool is_requirable = true; }; template struct object { template friend constexpr object require(const object&, prop) { return object(); } }; int main() { static_assert(asio::can_require_v, prop<2>>, ""); static_assert(asio::can_require_v, prop<2>, prop<3>>, ""); static_assert(asio::can_require_v, prop<2>, prop<3>, prop<4>>, ""); static_assert(asio::can_require_v, prop<2>>, ""); static_assert(asio::can_require_v, prop<2>, prop<3>>, ""); static_assert(asio::can_require_v, prop<2>, prop<3>, prop<4>>, ""); }