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The C and C++ Include Header Files

cat -n /usr/include/c++/15/ext/stdio_filebuf.h

     1	// File descriptor layer for filebuf -*- C++ -*-
     2	
     3	// Copyright (C) 2002-2025 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 ext/stdio_filebuf.h
    26	 *  This file is a GNU extension to the Standard C++ Library.
    27	 */
    28	
    29	#ifndef _STDIO_FILEBUF_H
    30	#define _STDIO_FILEBUF_H 1
    31	
    32	#ifdef _GLIBCXX_SYSHDR
    33	#pragma GCC system_header
    34	#endif
    35	
    36	#include <bits/requires_hosted.h> // GNU extensions are currently omitted
    37	
    38	#include <fstream>
    39	
    40	namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
    41	{
    42	_GLIBCXX_BEGIN_NAMESPACE_VERSION
    43	
    44	  /**
    45	   *  @brief Provides a layer of compatibility for C/POSIX.
    46	   *  @ingroup io
    47	   *
    48	   *  This GNU extension provides extensions for working with standard C
    49	   *  FILE*'s and POSIX file descriptors.  It must be instantiated by the
    50	   *  user with the type of character used in the file stream, e.g.,
    51	   *  stdio_filebuf<char>.
    52	  */
    53	  template<typename _CharT, typename _Traits = std::char_traits<_CharT> >
    54	    class stdio_filebuf : public std::basic_filebuf<_CharT, _Traits>
    55	    {
    56	    public:
    57	      // Types:
    58	      typedef _CharT				        char_type;
    59	      typedef _Traits				        traits_type;
    60	      typedef typename traits_type::int_type		int_type;
    61	      typedef typename traits_type::pos_type		pos_type;
    62	      typedef typename traits_type::off_type		off_type;
    63	      typedef std::size_t                               size_t;
    64	
    65	    public:
    66	      /**
    67	       * deferred initialization
    68	      */
    69	      stdio_filebuf() : std::basic_filebuf<_CharT, _Traits>() {}
    70	
    71	      /**
    72	       *  @param  __fd  An open file descriptor.
    73	       *  @param  __mode  Same meaning as in a standard filebuf.
    74	       *  @param  __size Optimal or preferred size of internal buffer,
    75	       *                 in chars.
    76	       *
    77	       *  This constructor associates a file stream buffer with an open
    78	       *  POSIX file descriptor. The file descriptor will be automatically
    79	       *  closed when the stdio_filebuf is closed/destroyed.
    80	      */
    81	      stdio_filebuf(int __fd, std::ios_base::openmode __mode,
    82			    size_t __size = static_cast<size_t>(_GLIBCXX_BUFSIZ));
    83	
    84	      /**
    85	       *  @param  __f  An open @c FILE*.
    86	       *  @param  __mode  Same meaning as in a standard filebuf.
    87	       *  @param  __size Optimal or preferred size of internal buffer,
    88	       *                 in chars.  Defaults to system's @c BUFSIZ.
    89	       *
    90	       *  This constructor associates a file stream buffer with an open
    91	       *  C @c FILE*.  The @c FILE* will not be automatically closed when the
    92	       *  stdio_filebuf is closed/destroyed.
    93	      */
    94	      stdio_filebuf(std::__c_file* __f, std::ios_base::openmode __mode,
    95			    size_t __size = static_cast<size_t>(_GLIBCXX_BUFSIZ));
    96	
    97	      /**
    98	       *  Closes the external data stream if the file descriptor constructor
    99	       *  was used.
   100	      */
   101	      virtual
   102	      ~stdio_filebuf();
   103	
   104	#if __cplusplus >= 201103L
   105	      stdio_filebuf(stdio_filebuf&&) = default;
   106	      stdio_filebuf& operator=(stdio_filebuf&&) = default;
   107	
   108	      void
   109	      swap(stdio_filebuf& __fb)
   110	      { std::basic_filebuf<_CharT, _Traits>::swap(__fb); }
   111	#endif
   112	
   113	      /**
   114	       *  @return  The underlying file descriptor.
   115	       *
   116	       *  Once associated with an external data stream, this function can be
   117	       *  used to access the underlying POSIX file descriptor.  Note that
   118	       *  there is no way for the library to track what you do with the
   119	       *  descriptor, so be careful.
   120	      */
   121	      int
   122	      fd() { return this->_M_file.fd(); }
   123	
   124	      /**
   125	       *  @return  The underlying FILE*.
   126	       *
   127	       *  This function can be used to access the underlying "C" file pointer.
   128	       *  Note that there is no way for the library to track what you do
   129	       *  with the file, so be careful.
   130	       */
   131	      std::__c_file*
   132	      file() { return this->_M_file.file(); }
   133	    };
   134	
   135	  template<typename _CharT, typename _Traits>
   136	    stdio_filebuf<_CharT, _Traits>::~stdio_filebuf()
   137	    { }
   138	
   139	  template<typename _CharT, typename _Traits>
   140	    stdio_filebuf<_CharT, _Traits>::
   141	    stdio_filebuf(int __fd, std::ios_base::openmode __mode, size_t __size)
   142	    {
   143	      this->_M_file.sys_open(__fd, __mode);
   144	      if (this->is_open())
   145		{
   146		  this->_M_mode = __mode;
   147		  this->_M_buf_size = __size;
   148		  this->_M_allocate_internal_buffer();
   149		  this->_M_reading = false;
   150		  this->_M_writing = false;
   151		  this->_M_set_buffer(-1);
   152		}
   153	    }
   154	
   155	  template<typename _CharT, typename _Traits>
   156	    stdio_filebuf<_CharT, _Traits>::
   157	    stdio_filebuf(std::__c_file* __f, std::ios_base::openmode __mode,
   158			  size_t __size)
   159	    {
   160	      this->_M_file.sys_open(__f, __mode);
   161	      if (this->is_open())
   162		{
   163		  this->_M_mode = __mode;
   164		  this->_M_buf_size = __size;
   165		  this->_M_allocate_internal_buffer();
   166		  this->_M_reading = false;
   167		  this->_M_writing = false;
   168		  this->_M_set_buffer(-1);
   169		}
   170	    }
   171	
   172	_GLIBCXX_END_NAMESPACE_VERSION
   173	} // namespace
   174	
   175	#endif