include/mpark/in_place.hpp

   1 // MPark.Variant
   2 //
   3 // Copyright Michael Park, 2015-2017
   4 //
   5 // Distributed under the Boost Software License, Version 1.0.
   6 // (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
   7
   8 #ifndef MPARK_IN_PLACE_HPP
   9 #define MPARK_IN_PLACE_HPP
  10
  11 #include <cstddef>
  12
  13 #include "config.hpp"
  14
  15 namespace mpark {
  16
  17   struct in_place_t { explicit in_place_t() = default; };
  18
  19   template <std::size_t I>
  20   struct in_place_index_t { explicit in_place_index_t() = default; };
  21
  22   template <typename T>
  23   struct in_place_type_t { explicit in_place_type_t() = default; };
  24
  25 #ifdef MPARK_VARIABLE_TEMPLATES
  26   constexpr in_place_t in_place{};
  27
  28   template <std::size_t I> constexpr in_place_index_t<I> in_place_index{};
  29
  30   template <typename T> constexpr in_place_type_t<T> in_place_type{};
  31 #endif
  32
  33 }  // namespace mpark
  34
  35 #endif  // MPARK_IN_PLACE_HPP