1.\" Copyright (c) 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)tcsendbreak.3 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD: src/lib/libc/gen/tcsendbreak.3,v 1.5.2.3 2001/12/14 18:33:51 ru Exp $ 34.\" $DragonFly: src/lib/libc/gen/tcsendbreak.3,v 1.2 2003/06/17 04:26:42 dillon Exp $ 35.\" 36.Dd June 4, 1993 37.Dt TCSENDBREAK 3 38.Os 39.Sh NAME 40.Nm tcsendbreak , 41.Nm tcdrain , 42.Nm tcflush , 43.Nm tcflow 44.Nd line control functions 45.Sh LIBRARY 46.Lb libc 47.Sh SYNOPSIS 48.In termios.h 49.Ft int 50.Fn tcdrain "int fd" 51.Ft int 52.Fn tcflow "int fd" "int action" 53.Ft int 54.Fn tcflush "int fd" "int action" 55.Ft int 56.Fn tcsendbreak "int fd" "int len" 57.Sh DESCRIPTION 58The 59.Fn tcdrain 60function waits until all output written to the terminal referenced by 61.Fa fd 62has been transmitted to the terminal. 63.Pp 64The 65.Fn tcflow 66function suspends transmission of data to or the reception of data from 67the terminal referenced by 68.Fa fd 69depending on the value of 70.Fa action . 71The value of 72.Fa action 73must be one of the following: 74.Bl -tag -width "TCIOFF" 75.It Fa TCOOFF 76Suspend output. 77.It Fa TCOON 78Restart suspended output. 79.It Fa TCIOFF 80Transmit a STOP character, which is intended to cause the terminal to stop 81transmitting data to the system. 82(See the description of IXOFF in the 83.Ql Input Modes 84section of 85.Xr termios 4 ) . 86.It Fa TCION 87Transmit a START character, which is intended to cause the terminal to start 88transmitting data to the system. 89(See the description of IXOFF in the 90.Ql Input Modes 91section of 92.Xr termios 4 ) . 93.El 94.Pp 95The 96.Fn tcflush 97function discards any data written to the terminal referenced by 98.Fa fd 99which has not been transmitted to the terminal, or any data received 100from the terminal but not yet read, depending on the value of 101.Fa action . 102The value of 103.Fa action 104must be one of the following: 105.Bl -tag -width "TCIOFLUSH" 106.It Fa TCIFLUSH 107Flush data received but not read. 108.It Fa TCOFLUSH 109Flush data written but not transmitted. 110.It Fa TCIOFLUSH 111Flush both data received but not read and data written but not transmitted. 112.El 113.Pp 114The 115.Fn tcsendbreak 116function transmits a continuous stream of zero-valued bits for four-tenths 117of a second to the terminal referenced by 118.Fa fd . 119The 120.Fa len 121parameter is ignored in this implementation. 122.Sh RETURN VALUES 123Upon successful completion, all of these functions return a value of zero. 124.Sh ERRORS 125If any error occurs, a value of -1 is returned and the global variable 126.Va errno 127is set to indicate the error, as follows: 128.Bl -tag -width Er 129.It Bq Er EBADF 130The 131.Fa fd 132argument is not a valid file descriptor. 133.It Bq Er EINVAL 134The 135.Fa action 136argument is not a proper value. 137.It Bq Er ENOTTY 138The file associated with 139.Fa fd 140is not a terminal. 141.It Bq Er EINTR 142A signal interrupted the 143.Fn tcdrain 144function. 145.El 146.Sh SEE ALSO 147.Xr tcsetattr 3 , 148.Xr termios 4 149.Sh STANDARDS 150The 151.Fn tcsendbreak , 152.Fn tcdrain , 153.Fn tcflush 154and 155.Fn tcflow 156functions are expected to be compliant with the 157.St -p1003.1-88 158specification. 159