lib/binary-io.h

   1 /* Binary mode I/O.
   2    Copyright (C) 2001, 2003, 2005, 2008-2012 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU Lesser General Public License as published by
   6    the Free Software Foundation; either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program 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
  12    GNU Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public License
  15    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  16
  17 #ifndef _BINARY_H
  18 #define _BINARY_H
  19
  20 /* For systems that distinguish between text and binary I/O.
  21    O_BINARY is guaranteed by the gnulib <fcntl.h>. */
  22 #include <fcntl.h>
  23
  24 /* The MSVC7 <stdio.h> doesn't like to be included after '#define fileno ...',
  25    so we include it here first.  */
  26 #include <stdio.h>
  27
  28 /* set_binary_mode (fd, mode)
  29    sets the binary/text I/O mode of file descriptor fd to the given mode
  30    (must be O_BINARY or O_TEXT) and returns the previous mode.  */
  31 #if O_BINARY
  32 # if defined __EMX__ || defined __DJGPP__ || defined __CYGWIN__
  33 #  include <io.h> /* declares setmode() */
  34 #  define set_binary_mode setmode
  35 # else
  36 #  define set_binary_mode _setmode
  37 #  undef fileno
  38 #  define fileno _fileno
  39 # endif
  40 #else
  41   /* On reasonable systems, binary I/O is the only choice.  */
  42   /* Use an inline function rather than a macro, to avoid gcc warnings
  43      "warning: statement with no effect".  */
  44 static inline int
  45 set_binary_mode (int fd, int mode)
  46 {
  47   (void) fd;
  48   (void) mode;
  49   return O_BINARY;
  50 }
  51 #endif
  52
  53 /* SET_BINARY (fd);
  54    changes the file descriptor fd to perform binary I/O.  */
  55 #ifdef __DJGPP__
  56 # include <unistd.h> /* declares isatty() */
  57   /* Avoid putting stdin/stdout in binary mode if it is connected to
  58      the console, because that would make it impossible for the user
  59      to interrupt the program through Ctrl-C or Ctrl-Break.  */
  60 # define SET_BINARY(fd) ((void) (!isatty (fd) ? (set_binary_mode (fd, O_BINARY), 0) : 0))
  61 #else
  62 # define SET_BINARY(fd) ((void) set_binary_mode (fd, O_BINARY))
  63 #endif
  64
  65 #endif /* _BINARY_H */