libio/oldstdfiles.c

   1 /* Copyright (C) 1993,94,96,97,99,2000,2002,2004 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.
  18
  19    As a special exception, if you link the code in this file with
  20    files compiled with a GNU compiler to produce an executable,
  21    that does not cause the resulting executable to be covered by
  22    the GNU Lesser General Public License.  This exception does not
  23    however invalidate any other reasons why the executable file
  24    might be covered by the GNU Lesser General Public License.
  25    This exception applies to code released by its copyright holders
  26    in files containing the exception.  */
  27
  28 #include <shlib-compat.h>
  29 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)
  30
  31 /* This file provides definitions of _IO_stdin, _IO_stdout, and _IO_stderr
  32    for C code.  Compare stdstreams.cc.
  33    (The difference is that here the vtable field is set to 0,
  34    so the objects defined are not valid C++ objects.  On the other
  35    hand, we don't need a C++ compiler to build this file.) */
  36
  37 #define _IO_USE_OLD_IO_FILE
  38 #include "libioP.h"
  39
  40 #ifdef _IO_MTSAFE_IO
  41 #define DEF_STDFILE(NAME, FD, CHAIN, FLAGS) \
  42   static _IO_lock_t _IO_stdfile_##FD##_lock = _IO_lock_initializer; \
  43   struct _IO_FILE_plus NAME \
  44     = {FILEBUF_LITERAL(CHAIN, FLAGS, FD, NULL), &_IO_old_file_jumps};
  45 #else
  46 #define DEF_STDFILE(NAME, FD, CHAIN, FLAGS) \
  47   struct _IO_FILE_plus NAME \
  48     = {FILEBUF_LITERAL(CHAIN, FLAGS, FD, NULL), &_IO_old_file_jumps};
  49 #endif
  50
  51 DEF_STDFILE(_IO_stdin_, 0, 0, _IO_NO_WRITES);
  52 DEF_STDFILE(_IO_stdout_, 1, &_IO_stdin_, _IO_NO_READS);
  53 DEF_STDFILE(_IO_stderr_, 2, &_IO_stdout_, _IO_NO_READS+_IO_UNBUFFERED);
  54
  55 #if defined __GNUC__ && __GNUC__ >= 2
  56
  57 #include <stdio.h>
  58
  59 extern const int _IO_stdin_used;
  60 weak_extern (_IO_stdin_used);
  61
  62 #undef stdin
  63 #undef stdout
  64 #undef stderr
  65
  66 extern FILE *stdin;
  67 extern FILE *stdout;
  68 extern FILE *stderr;
  69
  70 static void _IO_check_libio (void) __THROW __attribute__ ((constructor));
  71
  72 /* This function determines which shared C library the application
  73    was linked against. We then set up the stdin/stdout/stderr and
  74    _IO_list_all accordingly. */
  75
  76 static void
  77 _IO_check_libio ()
  78 {
  79   if (&_IO_stdin_used == NULL)
  80     {
  81       /* We are using the old one. */
  82       _IO_stdin = stdin = (_IO_FILE *) &_IO_stdin_;
  83       _IO_stdout = stdout = (_IO_FILE *) &_IO_stdout_;
  84       _IO_stderr = stderr = (_IO_FILE *) &_IO_stderr_;
  85       INTUSE(_IO_list_all) = &_IO_stderr_;
  86       _IO_stdin->_vtable_offset = _IO_stdout->_vtable_offset =
  87         _IO_stderr->_vtable_offset = stdin->_vtable_offset =
  88         stdout->_vtable_offset = stderr->_vtable_offset =
  89         ((int) sizeof (struct _IO_FILE)
  90          - (int) sizeof (struct _IO_FILE_complete));
  91     }
  92 }
  93
  94 #endif
  95
  96 #endif