'\" 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 tcdrain 3 2026-07-02 "Linux man-pages 6.19"
.SH NAME
tcdrain
\-
block until output is transmitted
.SH LIBRARY
Standard C library
.RI ( libc ,\~ \-lc )
.SH SYNOPSIS
.nf
.B #include <termios.h>
.P
.BI "int tcdrain(int " fd );
.fi
.SH DESCRIPTION
.BR tcdrain ()
waits until all output written to the object referred to by
.I fd
has been 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 tcdrain ()
T}	Thread safety	MT-Safe
.TE
.SH STANDARDS
POSIX.1-2008.
.SH HISTORY
POSIX.1-2001.
.SH SEE ALSO
.BR tcsendbreak (3),
.BR tcflush (3),
.BR tcflow (3),
.BR termios (7)