'\" t
.\" Copyright 2006-2015, Michael Kerrisk <mtk.manpages@gmail.com>
.\" Copyright, the authors of the Linux man-pages project
.\"
.\" SPDX-License-Identifier: GPL-2.0-or-later
.\"
.TH tcflush 3 2026-07-02 "Linux man-pages 6.19"
.SH NAME
tcflush
\-
discard pending data
.SH LIBRARY
Standard C library
.RI ( libc ,\~ \-lc )
.SH SYNOPSIS
.nf
.B #include <termios.h>
.P
.BI "int tcflush(int " fd ", int " queue_selector );
.fi
.SH DESCRIPTION
.BR tcflush ()
discards data written to the object referred to by
.I fd
but not transmitted,
or data received but not read,
depending on the value of
.IR queue_selector :
.TP
.B TCIFLUSH
flushes data received but not read.
.TP
.B TCOFLUSH
flushes data written but not transmitted.
.TP
.B TCIOFLUSH
flushes both data received but not read,
and data written but not transmitted.
.SH RETURN VALUE
.TP
.B 0
on success.
.TP
.B \-1
on failure and set
.I errno
to indicate the error.
.SH ATTRIBUTES
For an explanation of the terms used in this section,
see
.BR attributes (7).
.TS
allbox;
lbx lb lb
l l l.
Interface	Attribute	Value
T{
.na
.nh
.BR tcflush ()
T}	Thread safety	MT-Safe
.TE
.SH STANDARDS
POSIX.1-2008.
.SH HISTORY
POSIX.1-2001.
.SH SEE ALSO
.BR tcsendbreak (3),
.BR tcdrain (3),
.BR tcflow (3),
.BR termios (7)