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