1 /* Copyright (C) 1998 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Zack Weinberg <zack@rabi.phys.columbia.edu>, 1998.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public License as
7 published by the Free Software Foundation; either version 2 of the
8 License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
14
15 You should have received a copy of the GNU Library General Public
16 License along with the GNU C Library; see the file COPYING.LIB. If not,
17 see <http://www.gnu.org/licenses/>. */
18
19 #include <errno.h>
20 #include <stdlib.h>
21 #include <sys/ioctl.h>
22 #include <termios.h>
23
24
25 /* Unlock the slave pseudo terminal associated with the master pseudo
26 terminal specified by FD. */
27 int
unlockpt(int fd)28 unlockpt (int fd)
29 {
30 #ifdef TIOCSPTLCK
31 int save_errno = errno;
32 int unlock = 0;
33
34 if (ioctl (fd, TIOCSPTLCK, &unlock))
35 {
36 if (errno == EINVAL)
37 {
38 errno = save_errno;
39 return 0;
40 }
41 else
42 return -1;
43 }
44 #endif
45 /* If we have no TIOCSPTLCK ioctl, all slave pseudo terminals are
46 unlocked by default. */
47 return 0;
48 }
49