1 // 2 // cpp14/can_query_free.cpp 3 // ~~~~~~~~~~~~~~~~~~~~~~~~ 4 // 5 // Copyright (c) 2003-2020 Christopher M. Kohlhoff (chris at kohlhoff dot com) 6 // 7 // Distributed under the Boost Software License, Version 1.0. (See accompanying 8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 9 // 10 11 #include <boost/asio/query.hpp> 12 #include <cassert> 13 14 struct prop 15 { 16 template <typename> static constexpr bool is_applicable_property_v = true; 17 }; 18 19 struct object 20 { query(const object &,prop)21 friend constexpr int query(const object&, prop) { return 123; } 22 }; 23 main()24int main() 25 { 26 static_assert(boost::asio::can_query_v<object, prop>, ""); 27 static_assert(boost::asio::can_query_v<const object, prop>, ""); 28 } 29