update ceph source to reef 18.1.2

[ceph.git] / ceph / src / boost / boost / pfr / detail / rvalue_t.hpp

// Copyright (c) 2016-2022 Antony Polukhin
//
// 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)

#ifndef BOOST_PFR_DETAIL_RVALUE_T_HPP
#define BOOST_PFR_DETAIL_RVALUE_T_HPP
#pragma once

#include <type_traits>
#include <utility>      // std::enable_if_t

// This header provides aliases rvalue_t and lvalue_t.
//
// Usage: template <class T> void foo(rvalue<T> rvalue);
//
// Those are useful for
//  * better type safety - you can validate at compile time that only rvalue reference is passed into the function
//  * documentation and readability - rvalue_t<T> is much better than T&&+SFINAE

namespace boost { namespace pfr { namespace detail {

/// Binds to rvalues only, no copying allowed.
template <class T
#ifdef BOOST_PFR_DETAIL_STRICT_RVALUE_TESTING
    , class = std::enable_if_t<std::is_rvalue_reference<T&&>::value>
#endif
>
using rvalue_t = T&&;

/// Binds to mutable lvalues only

}}} // namespace boost::pfr::detail

#endif // BOOST_PFR_DETAIL_RVALUE_T_HPP