include/boost/implicit_cast.hpp

0001 // Copyright David Abrahams 2003.
0002 // Distributed under the Boost Software License, Version 1.0. (See
0003 // accompanying file LICENSE_1_0.txt or copy at
0004 // http://www.boost.org/LICENSE_1_0.txt)
0005
0006 #ifndef BOOST_IMPLICIT_CAST_DWA200356_HPP
0007 #define BOOST_IMPLICIT_CAST_DWA200356_HPP
0008
0009 #include <boost/config.hpp>
0010 #ifdef BOOST_HAS_PRAGMA_ONCE
0011 # pragma once
0012 #endif
0013
0014 namespace boost {
0015
0016 namespace detail {
0017
0018 template<class T> struct icast_identity
0019 {
0020     using type = T;
0021 };
0022
0023 } // namespace detail
0024
0025 // implementation originally suggested by C. Green in
0026 // http://lists.boost.org/MailArchives/boost/msg00886.php
0027
0028 // The use of identity creates a non-deduced form, so that the
0029 // explicit template argument must be supplied
0030 template <typename T>
0031 constexpr T implicit_cast (typename boost::detail::icast_identity<T>::type x) {
0032     return x;
0033 }
0034
0035 } // namespace boost
0036
0037
0038 #endif // BOOST_IMPLICIT_CAST_DWA200356_HPP