1//
2// cpp14/can_prefer_member_prefer.cpp
3// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
4//
5// Copyright (c) 2003-2024 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/prefer.hpp>
12#include <cassert>
13
14template <int>
15struct prop
16{
17 template <typename> static constexpr bool is_applicable_property_v = true;
18 static constexpr bool is_preferable = true;
19};
20
21template <int>
22struct object
23{
24 template <int N>
25 constexpr object<N> prefer(prop<N>) const
26 {
27 return object<N>();
28 }
29};
30
31int main()
32{
33 static_assert(boost::asio::can_prefer_v<object<1>, prop<2>>, "");
34 static_assert(boost::asio::can_prefer_v<object<1>, prop<2>, prop<3>>, "");
35 static_assert(boost::asio::can_prefer_v<object<1>, prop<2>, prop<3>, prop<4>>, "");
36 static_assert(boost::asio::can_prefer_v<const object<1>, prop<2>>, "");
37 static_assert(boost::asio::can_prefer_v<const object<1>, prop<2>, prop<3>>, "");
38 static_assert(boost::asio::can_prefer_v<const object<1>, prop<2>, prop<3>, prop<4>>, "");
39}
40

source code of boost/libs/asio/test/properties/cpp14/can_prefer_member_prefer.cpp