1 /*
2 Copyright 2017-2018 Glen Joseph Fernandes
3 ([email protected])
4 
5 Distributed under the Boost Software License,
6 Version 1.0. (See accompanying file LICENSE_1_0.txt
7 or copy at http://www.boost.org/LICENSE_1_0.txt)
8 */
9 
10 #ifndef BOOST_TT_IS_DETECTED_HPP_INCLUDED
11 #define BOOST_TT_IS_DETECTED_HPP_INCLUDED
12 
13 #include <boost/type_traits/detail/detector.hpp>
14 #include <boost/type_traits/nonesuch.hpp>
15 
16 namespace boost {
17 
18 template<template<class...> class Op, class... Args>
19 using is_detected = typename
20     detail::detector<nonesuch, void, Op, Args...>::value_t;
21 
22 #if !defined(BOOST_NO_CXX14_VARIABLE_TEMPLATES)
23 template<template<class...> class Op, class... Args>
24 constexpr bool is_detected_v = is_detected<Op, Args...>::value;
25 #endif
26 
27 } /* boost */
28 
29 #endif
30