.\" Copyright, the authors of the Linux man-pages project
.\"
.\" SPDX-License-Identifier: GPL-1.0-or-later
.\"
.TH TIOCSWINSZ 2const (date) "Linux man-pages (unreleased)"
.SH NAME
TIOCGWINSZ,
TIOCSWINSZ
\-
get and set window size
.SH LIBRARY
Standard C library
.RI ( libc ,\~ \-lc )
.SH SYNOPSIS
.nf
.BR "#include <asm/termbits.h>" "  /* Definition of " TIOC*WINSZ " constants */"
.B #include <sys/ioctl.h>
.P
.BI "int ioctl(int " fd ", TIOCGWINSZ, struct winsize *" argp );
.BI "int ioctl(int " fd ", TIOCSWINSZ, const struct winsize *" argp );
.P
.B #include <asm/termios.h>
.P
.B struct winsize {
.B "    unsigned short ws_row;"
.B "    unsigned short ws_col;"
.BR "    unsigned short ws_xpixel;" "  /* unused */"
.BR "    unsigned short ws_ypixel;" "  /* unused */"
.B };
.fi
.SH DESCRIPTION
Window sizes are kept in the kernel, but not used by the kernel
(except in the case of virtual consoles, where the kernel will
update the window size when the size of the virtual console changes,
for example, by loading a new font).
.TP
.B TIOCGWINSZ
Get window size.
.TP
.B TIOCSWINSZ
Set window size.
.P
When the window size changes, a
.B SIGWINCH
signal is sent to the
foreground process group.
.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 (2const)