| // |
| // cpp11/can_require_free.cpp |
| // ~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| // |
| // Copyright (c) 2003-2021 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 <boost/asio/require.hpp> |
| #include <cassert> |
| |
| template <int> |
| struct prop |
| { |
| static constexpr bool is_requirable = true; |
| }; |
| |
| template <int> |
| struct object |
| { |
| template <int N> |
| friend constexpr object<N> require(const object&, prop<N>) |
| { |
| return object<N>(); |
| } |
| }; |
| |
| namespace boost { |
| namespace asio { |
| |
| template<int N, int M> |
| struct is_applicable_property<object<N>, prop<M> > |
| { |
| static constexpr bool value = true; |
| }; |
| |
| } // namespace asio |
| } // namespace boost |
| |
| int main() |
| { |
| static_assert(boost::asio::can_require<object<1>, prop<2>>::value, ""); |
| static_assert(boost::asio::can_require<object<1>, prop<2>, prop<3>>::value, ""); |
| static_assert(boost::asio::can_require<object<1>, prop<2>, prop<3>, prop<4>>::value, ""); |
| static_assert(boost::asio::can_require<const object<1>, prop<2>>::value, ""); |
| static_assert(boost::asio::can_require<const object<1>, prop<2>, prop<3>>::value, ""); |
| static_assert(boost::asio::can_require<const object<1>, prop<2>, prop<3>, prop<4>>::value, ""); |
| } |