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.\" 34.Dd "June 4, 1993" 35.Dt TCSENDBREAK 3 36.Os 37.Sh NAME 38.Nm tcsendbreak , 39.Nm tcdrain , 40.Nm tcflush , 41.Nm tcflow 42.Nd line control functions 43.Sh SYNOPSIS 44.Fd #include <termios.h> 45.Ft int 46.Fn tcdrain "int fd" 47.Ft int 48.Fn tcflow "int fd" "int action" 49.Ft int 50.Fn tcflush "int fd" "int action" 51.Ft int 52.Fn tcsendbreak "int fd" "int len" 53.Sh DESCRIPTION 54The 55.Nm tcdrain 56function waits until all output written to the terminal referenced by 57.Fa fd 58has been transmitted to the terminal. 59.Pp 60The 61.Nm tcflow 62function suspends transmission of data to or the reception of data from 63the terminal referenced by 64.Fa fd 65depending on the value of 66.Fa action . 67The value of 68.Fa action 69must be one of the following: 70.Bl -tag -width "TCIOFF" 71.It Fa TCOOFF 72Suspend output. 73.It Fa TCOON 74Restart suspended output. 75.It Fa TCIOFF 76Transmit a STOP character, which is intended to cause the terminal to stop 77transmitting data to the system. 78(See the description of IXOFF in the 79.Ql Input Modes 80section of 81.Xr termios 4 ). 82.It Fa TCION 83Transmit a START character, which is intended to cause the terminal to start 84transmitting data to the system. 85(See the description of IXOFF in the 86.Ql Input Modes 87section of 88.Xr termios 4 ). 89.El 90.Pp 91The 92.Nm tcflush 93function discards any data written to the terminal referenced by 94.Fa fd 95which has not been transmitted to the terminal, or any data received 96from the terminal but not yet read, depending on the value of 97.Fa action . 98The value of 99.Fa action 100must be one of the following: 101.Bl -tag -width "TCIOFLUSH" 102.It Fa TCIFLUSH 103Flush data received but not read. 104.It Fa TCOFLUSH 105Flush data written but not transmitted. 106.It Fa TCIOFLUSH 107Flush both data received but not read and data written but not transmitted. 108.El 109.Pp 110The 111.Nm tcsendbreak 112function transmits a continuous stream of zero-valued bits for four-tenths 113of a second to the terminal referenced by 114.Fa fd . 115The 116.Fa len 117parameter is ignored in this implementation. 118.Sh RETURN VALUES 119Upon successful completion, all of these functions return a value of zero. 120.Sh ERRORS 121If any error occurs, a value of -1 is returned and the global variable 122.Va errno 123is set to indicate the error, as follows: 124.Bl -tag -width Er 125.It Bq Er EBADF 126The 127.Fa fd 128argument is not a valid file descriptor. 129.It Bq Er EINVAL 130The 131.Fa action 132argument is not a proper value. 133.It Bq Er ENOTTY 134The file associated with 135.Fa fd 136is not a terminal. 137.It Bq Er EINTR 138A signal interrupted the 139.Nm tcdrain 140function. 141.El 142.Sh SEE ALSO 143.Xr tcsetattr 3 , 144.Xr termios 4 145.Sh STANDARDS 146The 147.Nm tcsendbreak , 148.Nm tcdrain , 149.Nm tcflush 150and 151.Nm tcflow 152functions are expected to be compliant with the 153.St -p1003.1-88 154specification. 155