// // cpp03/prefer_unsupported.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 const bool is_preferable = true; }; template struct object { }; namespace asio { template struct is_applicable_property, prop > { static const bool value = true; }; } // namespace asio int main() { object<1> o1 = {}; const object<1>& o2 = asio::prefer(o1, prop<1>()); assert(&o1 == &o2); (void)o2; const object<1> o3 = {}; const object<1>& o4 = asio::prefer(o3, prop<1>()); assert(&o3 == &o4); (void)o4; }