// // cpp03/can_query_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/query.hpp" #include struct prop { }; struct object { friend int query(const object&, prop) { return 123; } }; namespace asio { template<> struct is_applicable_property { static const bool value = true; }; namespace traits { template<> struct query_free { static const bool is_valid = true; static const bool is_noexcept = true; typedef int result_type; }; } // namespace traits } // namespace asio int main() { assert((asio::can_query::value)); assert((asio::can_query::value)); }