boost/type_traits/is_detected.hpp
/* Copyright 2017-2018 Glen Joseph Fernandes (glenjofe@gmail.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) */ #ifndef BOOST_TT_IS_DETECTED_HPP_INCLUDED #define BOOST_TT_IS_DETECTED_HPP_INCLUDED #include <boost/type_traits/detail/detector.hpp> #include <boost/type_traits/nonesuch.hpp> namespace boost { template<template<class...> class Op, class... Args> using is_detected = typename detail::detector<nonesuch, void, Op, Args...>::value_t; #if !defined(BOOST_NO_CXX14_VARIABLE_TEMPLATES) template<template<class...> class Op, class... Args> constexpr bool is_detected_v = is_detected<Op, Args...>::value; #endif } /* boost */ #endif