51 lines
1.3 KiB
C++
51 lines
1.3 KiB
C++
//
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// cpp11/can_prefer_member_require.cpp
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// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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//
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// Copyright (c) 2003-2021 Christopher M. Kohlhoff (chris at kohlhoff dot com)
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#include <boost/asio/prefer.hpp>
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#include <cassert>
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template <int>
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struct prop
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{
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static constexpr bool is_preferable = true;
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};
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template <int>
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struct object
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{
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template <int N>
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constexpr object<N> require(prop<N>) const
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{
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return object<N>();
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}
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};
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namespace boost {
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namespace asio {
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template<int N, int M>
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struct is_applicable_property<object<N>, prop<M> >
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{
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static constexpr bool value = true;
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};
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} // namespace asio
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} // namespace boost
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int main()
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{
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static_assert(boost::asio::can_prefer<object<1>, prop<2>>::value, "");
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static_assert(boost::asio::can_prefer<object<1>, prop<2>, prop<3>>::value, "");
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static_assert(boost::asio::can_prefer<object<1>, prop<2>, prop<3>, prop<4>>::value, "");
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static_assert(boost::asio::can_prefer<const object<1>, prop<2>>::value, "");
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static_assert(boost::asio::can_prefer<const object<1>, prop<2>, prop<3>>::value, "");
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static_assert(boost::asio::can_prefer<const object<1>, prop<2>, prop<3>, prop<4>>::value, "");
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}
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