ceph/src/boost/libs/asio/test/properties/cpp11/can_prefer_free_prefer.cpp

   1 //
   2 // cpp11/can_prefer_free_prefer.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/prefer.hpp>
  12 #include <cassert>
  13
  14 template <int>
  15 struct prop
  16 {
  17   static constexpr bool is_preferable = true;
  18 };
  19
  20 template <int>
  21 struct object
  22 {
  23   template <int N>
  24   friend constexpr object<N> prefer(const object&, prop<N>)
  25   {
  26     return object<N>();
  27   }
  28 };
  29
  30 namespace boost {
  31 namespace asio {
  32
  33 template<int N, int M>
  34 struct is_applicable_property<object<N>, prop<M> >
  35 {
  36   static constexpr bool value = true;
  37 };
  38
  39 } // namespace asio
  40 } // namespace boost
  41
  42 int main()
  43 {
  44   static_assert(boost::asio::can_prefer<object<1>, prop<2>>::value, "");
  45   static_assert(boost::asio::can_prefer<object<1>, prop<2>, prop<3>>::value, "");
  46   static_assert(boost::asio::can_prefer<object<1>, prop<2>, prop<3>, prop<4>>::value, "");
  47   static_assert(boost::asio::can_prefer<const object<1>, prop<2>>::value, "");
  48   static_assert(boost::asio::can_prefer<const object<1>, prop<2>, prop<3>>::value, "");
  49   static_assert(boost::asio::can_prefer<const object<1>, prop<2>, prop<3>, prop<4>>::value, "");
  50 }