ceph/src/boost/libs/asio/test/properties/cpp14/prefer_free_prefer.cpp

   1 //
   2 // cpp14/prefer_free_prefer.cpp
   3 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2022 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   template <typename> static constexpr bool is_applicable_property_v = true;
  18   static constexpr bool is_preferable = true;
  19 };
  20
  21 template <int>
  22 struct object
  23 {
  24   template <int N>
  25   friend constexpr object<N> prefer(const object&, prop<N>)
  26   {
  27     return object<N>();
  28   }
  29 };
  30
  31 int main()
  32 {
  33   object<1> o1 = {};
  34   object<2> o2 = boost::asio::prefer(o1, prop<2>());
  35   object<3> o3 = boost::asio::prefer(o1, prop<2>(), prop<3>());
  36   object<4> o4 = boost::asio::prefer(o1, prop<2>(), prop<3>(), prop<4>());
  37   (void)o2;
  38   (void)o3;
  39   (void)o4;
  40
  41   const object<1> o5 = {};
  42   object<2> o6 = boost::asio::prefer(o5, prop<2>());
  43   object<3> o7 = boost::asio::prefer(o5, prop<2>(), prop<3>());
  44   object<4> o8 = boost::asio::prefer(o5, prop<2>(), prop<3>(), prop<4>());
  45   (void)o6;
  46   (void)o7;
  47   (void)o8;
  48
  49   constexpr object<2> o9 = boost::asio::prefer(object<1>(), prop<2>());
  50   constexpr object<3> o10 = boost::asio::prefer(object<1>(), prop<2>(), prop<3>());
  51   constexpr object<4> o11 = boost::asio::prefer(object<1>(), prop<2>(), prop<3>(), prop<4>());
  52   (void)o9;
  53   (void)o10;
  54   (void)o11;
  55 }