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The C and C++ Include Header Files

cat -n /usr/include/c++/15/experimental/iterator

     1	// <experimental/iterator> -*- C++ -*-
     2	
     3	// Copyright (C) 2015-2025 Free Software Foundation, Inc.
     4	//
     5	// This file is part of the GNU ISO C++ Library.  This library is free
     6	// software; you can redistribute it and/or modify it under the
     7	// terms of the GNU General Public License as published by the
     8	// Free Software Foundation; either version 3, or (at your option)
     9	// any later version.
    10	
    11	// This library is distributed in the hope that it will be useful,
    12	// but WITHOUT ANY WARRANTY; without even the implied warranty of
    13	// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    14	// GNU General Public License for more details.
    15	
    16	// Under Section 7 of GPL version 3, you are granted additional
    17	// permissions described in the GCC Runtime Library Exception, version
    18	// 3.1, as published by the Free Software Foundation.
    19	
    20	// You should have received a copy of the GNU General Public License and
    21	// a copy of the GCC Runtime Library Exception along with this program;
    22	// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
    23	// <http://www.gnu.org/licenses/>.
    24	
    25	/** @file experimental/iterator
    26	 *  This is a TS C++ Library header.
    27	 *  @ingroup libfund-ts
    28	 */
    29	
    30	//
    31	// N4336 Working Draft, C++ Extensions for Library Fundamentals, Version 2
    32	//
    33	
    34	#ifndef _GLIBCXX_EXPERIMENTAL_ITERATOR
    35	#define _GLIBCXX_EXPERIMENTAL_ITERATOR 1
    36	
    37	#ifdef _GLIBCXX_SYSHDR
    38	#pragma GCC system_header
    39	#endif
    40	
    41	#include <bits/requires_hosted.h> // experimental is currently omitted
    42	
    43	#if __cplusplus >= 201402L
    44	
    45	#include <iterator>
    46	#include <iosfwd>
    47	#include <experimental/type_traits>
    48	
    49	namespace std _GLIBCXX_VISIBILITY(default)
    50	{
    51	_GLIBCXX_BEGIN_NAMESPACE_VERSION
    52	
    53	namespace experimental
    54	{
    55	inline namespace fundamentals_v2
    56	{
    57	#define __cpp_lib_experimental_ostream_joiner 201411
    58	
    59	  /// Output iterator that inserts a delimiter between elements.
    60	  template<typename _DelimT, typename _CharT = char,
    61		   typename _Traits = char_traits<_CharT>>
    62	  class ostream_joiner
    63	  {
    64	  public:
    65	    typedef _CharT				char_type;
    66	    typedef _Traits				traits_type;
    67	    typedef basic_ostream<_CharT, _Traits>	ostream_type;
    68	    typedef output_iterator_tag			iterator_category;
    69	    typedef void				value_type;
    70	    typedef void				difference_type;
    71	    typedef void				pointer;
    72	    typedef void				reference;
    73	
    74	    ostream_joiner(ostream_type& __os, const _DelimT& __delimiter)
    75	    noexcept(is_nothrow_copy_constructible_v<_DelimT>)
    76	    : _M_out(std::__addressof(__os)), _M_delim(__delimiter)
    77	    { }
    78	
    79	    ostream_joiner(ostream_type& __os, _DelimT&& __delimiter)
    80	    noexcept(is_nothrow_move_constructible_v<_DelimT>)
    81	    : _M_out(std::__addressof(__os)), _M_delim(std::move(__delimiter))
    82	    { }
    83	
    84	    template<typename _Tp>
    85	      ostream_joiner&
    86	      operator=(const _Tp& __value)
    87	      {
    88		if (!_M_first)
    89		  *_M_out << _M_delim;
    90		_M_first = false;
    91		*_M_out << __value;
    92		return *this;
    93	      }
    94	
    95	    ostream_joiner& operator*() noexcept { return *this; }
    96	    ostream_joiner& operator++() noexcept { return *this; }
    97	    ostream_joiner& operator++(int) noexcept { return *this; }
    98	
    99	  private:
   100	    ostream_type* _M_out;
   101	    _DelimT _M_delim;
   102	    bool _M_first = true;
   103	  };
   104	
   105	  /// Object generator for ostream_joiner.
   106	  template<typename _CharT, typename _Traits, typename _DelimT>
   107	    inline ostream_joiner<decay_t<_DelimT>, _CharT, _Traits>
   108	    make_ostream_joiner(basic_ostream<_CharT, _Traits>& __os,
   109				_DelimT&& __delimiter)
   110	    { return { __os, std::forward<_DelimT>(__delimiter) }; }
   111	} // namespace fundamentals_v2
   112	} // namespace experimental
   113	
   114	_GLIBCXX_END_NAMESPACE_VERSION
   115	} // namespace std
   116	
   117	#endif // __cplusplus <= 201103L
   118	
   119	#endif // _GLIBCXX_EXPERIMENTAL_ITERATOR