ceph/src/boost/boost/hana/fwd/union.hpp

   1 /*!
   2 @file
   3 Forward declares `boost::hana::union_`.
   4
   5 @copyright Louis Dionne 2013-2017
   6 Distributed under the Boost Software License, Version 1.0.
   7 (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
   8  */
   9
  10 #ifndef BOOST_HANA_FWD_UNION_HPP
  11 #define BOOST_HANA_FWD_UNION_HPP
  12
  13 #include <boost/hana/config.hpp>
  14 #include <boost/hana/core/when.hpp>
  15
  16
  17 BOOST_HANA_NAMESPACE_BEGIN
  18     // Note: This function is documented per datatype/concept only.
  19     //! @cond
  20     template <typename T, typename = void>
  21     struct union_impl : union_impl<T, when<true>> { };
  22     //! @endcond
  23
  24     struct union_t {
  25         template <typename Xs, typename Ys>
  26         constexpr auto operator()(Xs&&, Ys&&) const;
  27     };
  28
  29     constexpr union_t union_{};
  30 BOOST_HANA_NAMESPACE_END
  31
  32 #endif // !BOOST_HANA_FWD_UNION_HPP