ceph/src/boost/boost/type_traits/is_detected.hpp

   1 /*
   2 Copyright 2017-2018 Glen Joseph Fernandes
   3 (glenjofe@gmail.com)
   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