boost/type_traits/enable_if.hpp

0001 /*
0002 Copyright 2003 The Trustees of Indiana University
0003
0004 Authors: Jaakko Jarvi (jajarvi at osl.iu.edu)
0005          Jeremiah Willcock (jewillco at osl.iu.edu)
0006          Andrew Lumsdaine (lums at osl.iu.edu)
0007
0008 Copyright 2018 Glen Joseph Fernandes
0009 (glenjofe@gmail.com)
0010
0011 Distributed under the Boost Software License,
0012 Version 1.0. (See accompanying file LICENSE_1_0.txt
0013 or copy at http://www.boost.org/LICENSE_1_0.txt)
0014 */
0015 #ifndef BOOST_TT_ENABLE_IF_HPP_INCLUDED
0016 #define BOOST_TT_ENABLE_IF_HPP_INCLUDED
0017
0018 #include <boost/config.hpp>
0019
0020 namespace boost {
0021
0022 template<bool B, class T = void>
0023 struct enable_if_ {
0024     typedef T type;
0025 };
0026
0027 template<class T>
0028 struct enable_if_<false, T> { };
0029
0030 #if !defined(BOOST_NO_CXX11_TEMPLATE_ALIASES)
0031 template<bool B, class T = void>
0032 using enable_if_t = typename enable_if_<B, T>::type;
0033 #endif
0034
0035 } /* boost */
0036
0037 #endif