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.\" Copyright, the authors of the Linux man-pages project
.\"
.\" SPDX-License-Identifier: GPL-1.0-or-later
.\"
.TH TIOCSSOFTCAR 2const 2025-05-17 "Linux man-pages (unreleased)"
.SH NAME
TIOCGSOFTCAR,
TIOCSSOFTCAR
\-
marking a line as local
.SH LIBRARY
Standard C library
.RI ( libc ,\~ \-lc )
.SH SYNOPSIS
.nf
.BR "#include <asm/termbits.h>" " /* Definition of " TIOC*SOFTCAR " constants */"
.B #include <sys/ioctl.h>
.P
.BI "int ioctl(int " fd ", TIOCGSOFTCAR, int *" argp );
.BI "int ioctl(int " fd ", TIOCSSOFTCAR, const int *" argp );
.fi
.SH DESCRIPTION
.TP
.B TIOCGSOFTCAR
("Get software carrier flag")
Get the status of the CLOCAL flag in the c_cflag field of the
.I termios
structure.
.TP
.B TIOCSSOFTCAR
("Set software carrier flag")
Set the CLOCAL flag in the
.I termios
structure when
.RI * argp
is nonzero, and clear it otherwise.
.P
If the
.B CLOCAL
flag for a line is off, the hardware carrier detect (DCD)
signal is significant, and an
.BR open (2)
of the corresponding terminal will block until DCD is asserted,
unless the
.B O_NONBLOCK
flag is given.
If
.B CLOCAL
is set, the line behaves as if DCD is always asserted.
The software carrier flag is usually turned on for local devices,
and is off for lines with modems.
.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)
|
