.\" Copyright 2002, Walter Harms <walter.harms@informatik.uni-oldenburg.de>
.\" Copyright 2002, Andries Brouwer <aeb@cwi.nl>
.\" Copyright 2024, Alejandro Colomar <alx@kernel.org>
.\"
.\" SPDX-License-Identifier: GPL-1.0-or-later
.\"
.TH TCSBRK 2const 2024-07-23 "Linux man-pages 6.10"
.SH NAME
TCSBRK,
TCSBRKP,
TIOCSBRK,
TIOCCBRK
\-
sending a break
.SH LIBRARY
Standard C library
.RI ( libc ,\~ \-lc )
.SH SYNOPSIS
.nf
.BR "#include <asm/termbits.h>" "  /* Definition of " T*BRK* " constants */"
.B #include <sys/ioctl.h>
.P
.BI "int ioctl(int " fd ", TCSBRK, int " arg );
.BI "int ioctl(int " fd ", TCSBRKP, int " arg );
.BI "int ioctl(int " fd ", TIOCSBRK);"
.BI "int ioctl(int " fd ", TIOCCBRK);"
.fi
.SH DESCRIPTION
.TP
.B TCSBRK
Equivalent to
.IR "tcsendbreak(fd, arg)" .
.IP
If the terminal is using asynchronous serial data transmission, and
.I arg
is zero, then send a break (a stream of zero bits) for between
0.25 and 0.5 seconds.
If the terminal is not using asynchronous
serial data transmission, then either a break is sent, or the function
returns without doing anything.
When
.I arg
is nonzero, nobody knows what will happen.
.IP
(SVr4, UnixWare, Solaris, and Linux treat
.I "tcsendbreak(fd,arg)"
with nonzero
.I arg
like
.IR "tcdrain(fd)" .
SunOS treats
.I arg
as a multiplier, and sends a stream of bits
.I arg
times as long as done for zero
.IR arg .
DG/UX and AIX treat
.I arg
(when nonzero) as a time interval measured in milliseconds.
HP-UX ignores
.IR arg .)
.TP
.B TCSBRKP
So-called "POSIX version" of
.BR TCSBRK .
It treats nonzero
.I arg
as a time interval measured in deciseconds, and does nothing
when the driver does not support breaks.
.TP
.B TIOCSBRK
Turn break on, that is, start sending zero bits.
.TP
.B TIOCCBRK
Turn break off, that is, stop sending zero bits.
.SH RETURN VALUE
On success,
0 is returned.
On error,
\-1 is returned, and
.I errno
is set to indicate the error.
.SH SEE ALSO
.BR ioctl (2),
.BR ioctl_tty (2)