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.\" $FreeBSD$ 34.\" 35.Dd June 4, 1993 36.Dt TCSENDBREAK 3 37.Os 38.Sh NAME 39.Nm tcsendbreak , 40.Nm tcdrain , 41.Nm tcflush , 42.Nm tcflow 43.Nd line control functions 44.Sh SYNOPSIS 45.Fd #include <termios.h> 46.Ft int 47.Fn tcdrain "int fd" 48.Ft int 49.Fn tcflow "int fd" "int action" 50.Ft int 51.Fn tcflush "int fd" "int action" 52.Ft int 53.Fn tcsendbreak "int fd" "int len" 54.Sh DESCRIPTION 55The 56.Fn tcdrain 57function waits until all output written to the terminal referenced by 58.Fa fd 59has been transmitted to the terminal. 60.Pp 61The 62.Fn tcflow 63function suspends transmission of data to or the reception of data from 64the terminal referenced by 65.Fa fd 66depending on the value of 67.Fa action . 68The value of 69.Fa action 70must be one of the following: 71.Bl -tag -width "TCIOFF" 72.It Fa TCOOFF 73Suspend output. 74.It Fa TCOON 75Restart suspended output. 76.It Fa TCIOFF 77Transmit a STOP character, which is intended to cause the terminal to stop 78transmitting data to the system. 79(See the description of IXOFF in the 80.Ql Input Modes 81section of 82.Xr termios 4 ). 83.It Fa TCION 84Transmit a START character, which is intended to cause the terminal to start 85transmitting data to the system. 86(See the description of IXOFF in the 87.Ql Input Modes 88section of 89.Xr termios 4 ). 90.El 91.Pp 92The 93.Fn tcflush 94function discards any data written to the terminal referenced by 95.Fa fd 96which has not been transmitted to the terminal, or any data received 97from the terminal but not yet read, depending on the value of 98.Fa action . 99The value of 100.Fa action 101must be one of the following: 102.Bl -tag -width "TCIOFLUSH" 103.It Fa TCIFLUSH 104Flush data received but not read. 105.It Fa TCOFLUSH 106Flush data written but not transmitted. 107.It Fa TCIOFLUSH 108Flush both data received but not read and data written but not transmitted. 109.El 110.Pp 111The 112.Fn tcsendbreak 113function transmits a continuous stream of zero-valued bits for four-tenths 114of a second to the terminal referenced by 115.Fa fd . 116The 117.Fa len 118parameter is ignored in this implementation. 119.Sh RETURN VALUES 120Upon successful completion, all of these functions return a value of zero. 121.Sh ERRORS 122If any error occurs, a value of -1 is returned and the global variable 123.Va errno 124is set to indicate the error, as follows: 125.Bl -tag -width Er 126.It Bq Er EBADF 127The 128.Fa fd 129argument is not a valid file descriptor. 130.It Bq Er EINVAL 131The 132.Fa action 133argument is not a proper value. 134.It Bq Er ENOTTY 135The file associated with 136.Fa fd 137is not a terminal. 138.It Bq Er EINTR 139A signal interrupted the 140.Fn tcdrain 141function. 142.El 143.Sh SEE ALSO 144.Xr tcsetattr 3 , 145.Xr termios 4 146.Sh STANDARDS 147The 148.Fn tcsendbreak , 149.Fn tcdrain , 150.Fn tcflush 151and 152.Fn tcflow 153functions are expected to be compliant with the 154.St -p1003.1-88 155specification. 156