1/* Send break to terminal.
2 Copyright (C) 1996-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the 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 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <errno.h>
20#include <stddef.h>
21#include <termios.h>
22#include <sys/ioctl.h>
23
24/* Send zero bits on FD. */
25int
26tcsendbreak (int fd, int duration)
27{
28 /* The break lasts 0.25 to 0.5 seconds if DURATION is zero,
29 and an implementation-defined period if DURATION is nonzero.
30 We define a positive DURATION to be number of milliseconds to break. */
31 if (duration <= 0)
32 return __ioctl (fd, TCSBRK, 0);
33
34#ifdef TCSBRKP
35 /* Probably Linux-specific: a positive third TCSBRKP ioctl argument is
36 defined to be the number of 100ms units to break. */
37 return __ioctl (fd, TCSBRKP, (duration + 99) / 100);
38#else
39 /* ioctl can't send a break of any other duration for us.
40 This could be changed to use trickery (e.g. lower speed and
41 send a '\0') to send the break, but for now just return an error. */
42 return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
43#endif
44}
45