libio/oldstdfiles.c

   1 /* Copyright (C) 1993, 1994, 1996, 1997 Free Software Foundation, Inc.
   2    This file is part of the GNU IO Library.
   3
   4    This library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU General Public License as
   6    published by the Free Software Foundation; either version 2, or (at
   7    your option) any later version.
   8
   9    This library is distributed in the hope that it will be useful, but
  10    WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this library; see the file COPYING.  If not, write to
  16    the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
  17    MA 02111-1307, USA.
  18
  19    As a special exception, if you link this library with files
  20    compiled with a GNU compiler to produce an executable, this does
  21    not cause the resulting executable to be covered by the GNU General
  22    Public License.  This exception does not however invalidate any
  23    other reasons why the executable file might be covered by the GNU
  24    General Public License.  */
  25
  26
  27 /* This file provides definitions of _IO_stdin, _IO_stdout, and _IO_stderr
  28    for C code.  Compare stdstreams.cc.
  29    (The difference is that here the vtable field is set to 0,
  30    so the objects defined are not valid C++ objects.  On the other
  31    hand, we don't need a C++ compiler to build this file.) */
  32
  33 #define _IO_USE_OLD_IO_FILE
  34 #include "libioP.h"
  35
  36 #ifdef _IO_MTSAFE_IO
  37 #define DEF_STDFILE(NAME, FD, CHAIN, FLAGS) \
  38   static _IO_lock_t _IO_stdfile_##FD##_lock = _IO_lock_initializer; \
  39   struct _IO_FILE_plus NAME \
  40     = {FILEBUF_LITERAL(CHAIN, FLAGS, FD), &_IO_old_file_jumps};
  41 #else
  42 #define DEF_STDFILE(NAME, FD, CHAIN, FLAGS) \
  43   struct _IO_FILE_plus NAME \
  44     = {FILEBUF_LITERAL(CHAIN, FLAGS, FD), &_IO_old_file_jumps};
  45 #endif
  46
  47 DEF_STDFILE(_IO_stdin_, 0, 0, _IO_NO_WRITES);
  48 DEF_STDFILE(_IO_stdout_, 1, &_IO_stdin_.file, _IO_NO_READS);
  49 DEF_STDFILE(_IO_stderr_, 2, &_IO_stdout_.file,
  50             _IO_NO_READS+_IO_UNBUFFERED);
  51
  52 #if defined __GNUC__ && __GNUC__ >= 2
  53
  54 #include <stdio.h>
  55
  56 extern const int _IO_stdin_used;
  57 weak_extern (_IO_stdin_used);
  58
  59 #undef stdin
  60 #undef stdout
  61 #undef stderr
  62
  63 extern FILE *stdin;
  64 extern FILE *stdout;
  65 extern FILE *stderr;
  66
  67 extern FILE *_IO_list_all;
  68
  69 static void _IO_check_libio __P ((void)) __attribute__ ((constructor));
  70
  71 /* This function determines which shared C library the application
  72    was linked against. We then set up the stdin/stdout/stderr and
  73    _IO_list_all accordingly. */
  74
  75 static void
  76 _IO_check_libio ()
  77 {
  78   if (&_IO_stdin_used == NULL)
  79     {
  80       /* We are using the old one. */
  81       _IO_stdin = stdin = &_IO_stdin_.file;
  82       _IO_stdout = stdout = &_IO_stdout_.file;
  83       _IO_stderr = stderr = _IO_list_all = &_IO_stderr_.file;
  84       _IO_stdin->_vtable_offset = _IO_stdout->_vtable_offset =
  85         _IO_stderr->_vtable_offset = stdin->_vtable_offset =
  86         stdout->_vtable_offset = stderr->_vtable_offset =
  87         ((int) sizeof (struct _IO_FILE)
  88          - (int) sizeof (struct _IO_FILE_complete));
  89     }
  90 }
  91
  92 #endif