1 //
2 // cpp03/prefer_static.cpp
3 // ~~~~~~~~~~~~~~~~~~~~~~~
4 //
5 // Copyright (c) 2003-2021 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
14 template <int>
15 struct prop
16 {
17 static const bool is_preferable = true;
18 };
19
20 template <int>
21 struct object
22 {
23 };
24
25 namespace boost {
26 namespace asio {
27
28 template<int N, int M>
29 struct is_applicable_property<object<N>, prop<M> >
30 {
31 static const bool value = true;
32 };
33
34 namespace traits {
35
36 template<int N>
37 struct static_require<object<N>, prop<N> >
38 {
39 static const bool is_valid = true;
40 };
41
42 } // namespace traits
43 } // namespace asio
44 } // namespace boost
45
main()46 int main()
47 {
48 object<1> o1 = {};
49 object<1> o2 = boost::asio::prefer(o1, prop<1>());
50 object<1> o3 = boost::asio::prefer(o1, prop<1>(), prop<1>());
51 object<1> o4 = boost::asio::prefer(o1, prop<1>(), prop<1>(), prop<1>());
52 (void)o2;
53 (void)o3;
54 (void)o4;
55
56 const object<1> o5 = {};
57 object<1> o6 = boost::asio::prefer(o5, prop<1>());
58 object<1> o7 = boost::asio::prefer(o5, prop<1>(), prop<1>());
59 object<1> o8 = boost::asio::prefer(o5, prop<1>(), prop<1>(), prop<1>());
60 (void)o6;
61 (void)o7;
62 (void)o8;
63 }
64