sysdeps/unix/bsd/isatty.c

   1 /* Copyright (C) 1991, 1995, 1996 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 Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 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 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <errno.h>
  20 #include <unistd.h>
  21 #include <sys/ioctl.h>
  22
  23 /* Return 1 if FD is a terminal, 0 if not.  */
  24 int
  25 __isatty (fd)
  26      int fd;
  27 {
  28   int save;
  29   int is_tty;
  30   struct sgttyb term;
  31
  32   save = errno;
  33   is_tty = __ioctl (fd, TIOCGETP, &term) == 0;
  34   __set_errno (save);
  35
  36   return is_tty;
  37 }
  38
  39 weak_alias (__isatty, isatty)