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The C and C++ Include Header Files

/usr/include/c++/13/ext/stdio_filebuf.h


$ cat -n /usr/include/c++/13/ext/stdio_filebuf.h

     1	// File descriptor layer for filebuf -*- C++ -*-
     2	
     3	// Copyright (C) 2002-2023 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	#pragma GCC system_header
    33	
    34	#include <bits/requires_hosted.h> // GNU extensions are currently omitted
    35	
    36	#include <fstream>
    37	
    38	namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
    39	{
    40	_GLIBCXX_BEGIN_NAMESPACE_VERSION
    41	
    42	  /**
    43	   *  @brief Provides a layer of compatibility for C/POSIX.
    44	   *  @ingroup io
    45	   *
    46	   *  This GNU extension provides extensions for working with standard C
    47	   *  FILE*'s and POSIX file descriptors.  It must be instantiated by the
    48	   *  user with the type of character used in the file stream, e.g.,
    49	   *  stdio_filebuf<char>.
    50	  */
    51	  template<typename _CharT, typename _Traits = std::char_traits<_CharT> >
    52	    class stdio_filebuf : public std::basic_filebuf<_CharT, _Traits>
    53	    {
    54	    public:
    55	      // Types:
    56	      typedef _CharT				        char_type;
    57	      typedef _Traits				        traits_type;
    58	      typedef typename traits_type::int_type		int_type;
    59	      typedef typename traits_type::pos_type		pos_type;
    60	      typedef typename traits_type::off_type		off_type;
    61	      typedef std::size_t                               size_t;
    62	
    63	    public:
    64	      /**
    65	       * deferred initialization
    66	      */
    67	      stdio_filebuf() : std::basic_filebuf<_CharT, _Traits>() {}
    68	
    69	      /**
    70	       *  @param  __fd  An open file descriptor.
    71	       *  @param  __mode  Same meaning as in a standard filebuf.
    72	       *  @param  __size Optimal or preferred size of internal buffer,
    73	       *                 in chars.
    74	       *
    75	       *  This constructor associates a file stream buffer with an open
    76	       *  POSIX file descriptor. The file descriptor will be automatically
    77	       *  closed when the stdio_filebuf is closed/destroyed.
    78	      */
    79	      stdio_filebuf(int __fd, std::ios_base::openmode __mode,
    80			    size_t __size = static_cast<size_t>(_GLIBCXX_BUFSIZ));
    81	
    82	      /**
    83	       *  @param  __f  An open @c FILE*.
    84	       *  @param  __mode  Same meaning as in a standard filebuf.
    85	       *  @param  __size Optimal or preferred size of internal buffer,
    86	       *                 in chars.  Defaults to system's @c BUFSIZ.
    87	       *
    88	       *  This constructor associates a file stream buffer with an open
    89	       *  C @c FILE*.  The @c FILE* will not be automatically closed when the
    90	       *  stdio_filebuf is closed/destroyed.
    91	      */
    92	      stdio_filebuf(std::__c_file* __f, std::ios_base::openmode __mode,
    93			    size_t __size = static_cast<size_t>(_GLIBCXX_BUFSIZ));
    94	
    95	      /**
    96	       *  Closes the external data stream if the file descriptor constructor
    97	       *  was used.
    98	      */
    99	      virtual
   100	      ~stdio_filebuf();
   101	
   102	#if __cplusplus >= 201103L
   103	      stdio_filebuf(stdio_filebuf&&) = default;
   104	      stdio_filebuf& operator=(stdio_filebuf&&) = default;
   105	
   106	      void
   107	      swap(stdio_filebuf& __fb)
   108	      { std::basic_filebuf<_CharT, _Traits>::swap(__fb); }
   109	#endif
   110	
   111	      /**
   112	       *  @return  The underlying file descriptor.
   113	       *
   114	       *  Once associated with an external data stream, this function can be
   115	       *  used to access the underlying POSIX file descriptor.  Note that
   116	       *  there is no way for the library to track what you do with the
   117	       *  descriptor, so be careful.
   118	      */
   119	      int
   120	      fd() { return this->_M_file.fd(); }
   121	
   122	      /**
   123	       *  @return  The underlying FILE*.
   124	       *
   125	       *  This function can be used to access the underlying "C" file pointer.
   126	       *  Note that there is no way for the library to track what you do
   127	       *  with the file, so be careful.
   128	       */
   129	      std::__c_file*
   130	      file() { return this->_M_file.file(); }
   131	    };
   132	
   133	  template<typename _CharT, typename _Traits>
   134	    stdio_filebuf<_CharT, _Traits>::~stdio_filebuf()
   135	    { }
   136	
   137	  template<typename _CharT, typename _Traits>
   138	    stdio_filebuf<_CharT, _Traits>::
   139	    stdio_filebuf(int __fd, std::ios_base::openmode __mode, size_t __size)
   140	    {
   141	      this->_M_file.sys_open(__fd, __mode);
   142	      if (this->is_open())
   143		{
   144		  this->_M_mode = __mode;
   145		  this->_M_buf_size = __size;
   146		  this->_M_allocate_internal_buffer();
   147		  this->_M_reading = false;
   148		  this->_M_writing = false;
   149		  this->_M_set_buffer(-1);
   150		}
   151	    }
   152	
   153	  template<typename _CharT, typename _Traits>
   154	    stdio_filebuf<_CharT, _Traits>::
   155	    stdio_filebuf(std::__c_file* __f, std::ios_base::openmode __mode,
   156			  size_t __size)
   157	    {
   158	      this->_M_file.sys_open(__f, __mode);
   159	      if (this->is_open())
   160		{
   161		  this->_M_mode = __mode;
   162		  this->_M_buf_size = __size;
   163		  this->_M_allocate_internal_buffer();
   164		  this->_M_reading = false;
   165		  this->_M_writing = false;
   166		  this->_M_set_buffer(-1);
   167		}
   168	    }
   169	
   170	_GLIBCXX_END_NAMESPACE_VERSION
   171	} // namespace
   172	
   173	#endif