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[glibc/history.git] / sysdeps / unix / bsd / isatty.c
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1 /* Copyright (C) 1991, 1995, 1996 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
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.
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.
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. */
19 #include <errno.h>
20 #include <unistd.h>
21 #include <sys/ioctl.h>
23 /* Return 1 if FD is a terminal, 0 if not. */
24 int
25 __isatty (fd)
26 int fd;
28 int save;
29 int is_tty;
30 struct sgttyb term;
32 save = errno;
33 is_tty = __ioctl (fd, TIOCGETP, &term) == 0;
34 __set_errno (save);
36 return is_tty;
39 weak_alias (__isatty, isatty)