xref: /illumos-gate/usr/src/man/man3c/tcflow.3c (revision bbf21555)

Sun Microsystems, Inc. gratefully acknowledges The Open Group for
permission to reproduce portions of its copyrighted documentation.
Original documentation from The Open Group can be obtained online at
http://www.opengroup.org/bookstore/.

The Institute of Electrical and Electronics Engineers and The Open
Group, have given us permission to reprint portions of their
documentation.

In the following statement, the phrase ``this text'' refers to portions
of the system documentation.

Portions of this text are reprinted and reproduced in electronic form
in the SunOS Reference Manual, from IEEE Std 1003.1, 2004 Edition,
Standard for Information Technology -- Portable Operating System
Interface (POSIX), The Open Group Base Specifications Issue 6,
Copyright (C) 2001-2004 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any discrepancy
between these versions and the original IEEE and The Open Group
Standard, the original IEEE and The Open Group Standard is the referee
document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html.

This notice shall appear on any product containing this material.

The contents of this file are subject to the terms of the
Common Development and Distribution License (the "License").
You may not use this file except in compliance with the License.

You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
or http://www.opensolaris.org/os/licensing.
See the License for the specific language governing permissions
and limitations under the License.

When distributing Covered Code, include this CDDL HEADER in each
file and include the License file at usr/src/OPENSOLARIS.LICENSE.
If applicable, add the following below this CDDL HEADER, with the
fields enclosed by brackets "[]" replaced with your own identifying
information: Portions Copyright [yyyy] [name of copyright owner]


Portions Copyright (c) 1992, X/Open Company Limited All Rights Reserved
Copyright (c) 2002, Sun Microsystems, Inc. All Rights Reserved

TCFLOW 3C "Aug 14, 2002"
NAME
tcflow - suspend or restart the transmission or reception of data
SYNOPSIS

#include <termios.h>

int tcflow(int fildes, int action);
DESCRIPTION

The tcflow() function suspends transmission or reception of data on the object referred to by fildes, depending on the value of action. The fildes argument is an open file descriptor associated with a terminal.

If action is TCOOFF, output is suspended.

If action is TCOON, suspended output is restarted.

If action is TCIOFF, the system transmits a STOP character, which is intended to cause the terminal device to stop transmitting data to the system.

If action is TCION, the system transmits a START character, which is intended to cause the terminal device to start transmitting data to the system.

The default on the opening of a terminal file is that neither its input nor its output are suspended.

Attempts to use tcflow() from a process which is a member of a background process group on a fildes associated with its controlling terminal, will cause the process group to be sent a SIGTTOU signal. If the calling process is blocking or ignoring SIGTTOU signals, the process is allowed to perform the operation, and no signal is sent.

RETURN VALUES

Upon successful completion, 0 is returned. Otherwise, -1 is returned and errno is set to indicate the error.

ERRORS

The tcflow() function will fail if: EBADF

The fildes argument is not a valid file descriptor.

EINVAL

The action argument is not a supported value.

ENOTTY

The file associated with fildes is not a terminal.

The tcflow() function may fail if: EIO

The process group of the writing process is orphaned, and the writing process is not ignoring or blocking SIGTTOU.

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:

ATTRIBUTE TYPE ATTRIBUTE VALUE
Interface Stability Standard
MT-Level MT-Safe, and Async-Signal-Safe
SEE ALSO

tcsendbreak (3C), termio (4I), attributes (7), standards (7)