55 lines
1.1 KiB
C++
55 lines
1.1 KiB
C++
//
|
|
// cpp11/require_concept_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_concept.hpp>
|
|
#include <cassert>
|
|
|
|
template <int>
|
|
struct prop
|
|
{
|
|
static constexpr bool is_requirable_concept = true;
|
|
};
|
|
|
|
template <int>
|
|
struct object
|
|
{
|
|
template <int N>
|
|
friend constexpr object<N> require_concept(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()
|
|
{
|
|
object<1> o1 = {};
|
|
object<2> o2 = boost::asio::require_concept(o1, prop<2>());
|
|
(void)o2;
|
|
|
|
const object<1> o3 = {};
|
|
object<2> o4 = boost::asio::require_concept(o3, prop<2>());
|
|
(void)o4;
|
|
|
|
constexpr object<2> o5 = boost::asio::require_concept(object<1>(), prop<2>());
|
|
(void)o5;
|
|
}
|