inplace_tags.h

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// Tag types for inplace construction. -*- C++ -*-
 
// Copyright (C) 2004-2026 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
 
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
 
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
 
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.
 
/** @file include/bits/inplace_tags.h
 *  This is an internal header file, included by other library headers.
 *  Do not attempt to use it directly. @headername{utility}
 *
 *  This file contains the parts of `<utility>` needed by other headers,
 *  so they don't need to include the whole of `<utility>`.
 */
 
#ifndef _GLIBCXX_INPLACE_TAGS_H
#define _GLIBCXX_INPLACE_TAGS_H 1
 
#ifdef _GLIBCXX_SYSHDR
#pragma GCC system_header
#endif
 
#if __cplusplus >= 201703L
 
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
 
  struct in_place_t {
    explicit in_place_t() = default;
  };
 
  inline constexpr in_place_t in_place{};
 
  template<typename _Tp> struct in_place_type_t
  {
    explicit in_place_type_t() = default;
  };
 
  template<typename _Tp>
    inline constexpr in_place_type_t<_Tp> in_place_type{};
 
  template<size_t _Idx> struct in_place_index_t
  {
    explicit in_place_index_t() = default;
  };
 
  template<size_t _Idx>
    inline constexpr in_place_index_t<_Idx> in_place_index{};
 
  template<typename>
    inline constexpr bool __is_in_place_type_v = false;
 
  template<typename _Tp>
    inline constexpr bool __is_in_place_type_v<in_place_type_t<_Tp>> = true;
 
  template<typename>
    inline constexpr bool __is_in_place_index_v = false;
 
  template<size_t _Nm>
    inline constexpr bool __is_in_place_index_v<in_place_index_t<_Nm>> = true;
 
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
 
#endif // C++17
#endif /* _GLIBCXX_INPLACE_TAGS_H */