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.\" @(#)tcsetattr.3 8.3 (Berkeley) 1/2/94 33.\" 34.Dd "January 2, 1994" 35.Dt TCSETATTR 3 36.Os 37.Sh NAME 38.Nm cfgetispeed , 39.Nm cfsetispeed , 40.Nm cfgetospeed , 41.Nm cfsetospeed , 42.Nm cfsetspeed , 43.Nm cfmakeraw , 44.Nm tcgetattr , 45.Nm tcsetattr 46.Nd manipulating the termios structure 47.Sh SYNOPSIS 48.Fd #include <termios.h> 49.Ft speed_t 50.Fn cfgetispeed "const struct termios *t" 51.Ft int 52.Fn cfsetispeed "struct termios *t" "speed_t speed" 53.Ft speed_t 54.Fn cfgetospeed "const struct termios *t" 55.Ft int 56.Fn cfsetospeed "struct termios *t" "speed_t speed" 57.Ft int 58.Fn cfsetspeed "struct termios *t" "speed_t speed" 59.Ft void 60.Fn cfmakeraw "struct termios *t" 61.Ft int 62.Fn tcgetattr "int fd" "struct termios *t" 63.Ft int 64.Fn tcsetattr "int fd" "int action" "const struct termios *t" 65.Sh DESCRIPTION 66The 67.Fn cfmakeraw , 68.Fn tcgetattr 69and 70.Fn tcsetattr 71functions are provided for getting and setting the termios structure. 72.Pp 73The 74.Fn cfgetispeed , 75.Fn cfsetispeed , 76.Fn cfgetospeed , 77.Fn cfsetospeed 78and 79.Fn cfsetspeed 80functions are provided for getting and setting the baud rate values in 81the termios structure. 82The effects of the functions on the terminal as described below 83do not become effective, nor are all errors detected, until the 84.Fn tcsetattr 85function is called. 86Certain values for baud rates set in the termios structure and passed to 87.Fn tcsetattr 88have special meanings. 89These are discussed in the portion of the manual page that describes the 90.Fn tcsetattr 91function. 92.Sh GETTING AND SETTING THE BAUD RATE 93The input and output baud rates are found in the termios structure. 94The unsigned integer 95.Li speed_t 96is typdef'd in the include file 97.Aq Pa termios.h . 98The value of the integer corresponds directly to the baud rate being 99represented, however, the following symbolic values are defined. 100.Bd -literal 101#define B0 0 102#define B50 50 103#define B75 75 104#define B110 110 105#define B134 134 106#define B150 150 107#define B200 200 108#define B300 300 109#define B600 600 110#define B1200 1200 111#define B1800 1800 112#define B2400 2400 113#define B4800 4800 114#define B9600 9600 115#define B19200 19200 116#define B38400 38400 117#ifndef _POSIX_SOURCE 118#define EXTA 19200 119#define EXTB 38400 120#endif /*_POSIX_SOURCE */ 121.Ed 122.Pp 123The 124.Fn cfgetispeed 125function returns the input baud rate in the termios structure referenced by 126.Fa tp . 127.Pp 128The 129.Fn cfsetispeed 130function sets the input baud rate in the termios structure referenced by 131.Fa tp 132to 133.Fa speed . 134.Pp 135The 136.Fn cfgetospeed 137function returns the output baud rate in the termios structure referenced by 138.Fa tp . 139.Pp 140The 141.Fn cfsetospeed 142function sets the output baud rate in the termios structure referenced by 143.Fa tp 144to 145.Fa speed . 146.Pp 147The 148.Fn cfsetspeed 149function sets both the input and output baud rate in the termios structure 150referenced by 151.Fa tp 152to 153.Fa speed . 154.Pp 155Upon successful completion, the functions 156.Fn cfsetispeed , 157.Fn cfsetospeed , 158and 159.Fn cfsetspeed 160return a value of 0. 161Otherwise, a value of -1 is returned and the global variable 162.Va errno 163is set to indicate the error. 164.Sh GETTING AND SETTING THE TERMIOS STATE 165This section describes the functions that are used to control the general 166terminal interface. 167Unless otherwise noted for a specific command, these functions are restricted 168from use by background processes. 169Attempts to perform these operations shall cause the process group to be sent 170a SIGTTOU signal. 171If the calling process is blocking or ignoring SIGTTOU signals, the process 172is allowed to perform the operation and the SIGTTOU signal is not sent. 173.Pp 174In all the functions, although 175.Fa fd 176is an open file descriptor, the functions affect the underlying terminal 177file, not just the open file description associated with the particular 178file descriptor. 179.Pp 180The 181.Fn cfmakeraw 182function sets the flags stored in the termios structure to a state disabling 183all input and output processing, giving a 184.Dq raw I/O path. 185It should be noted that there is no function to reverse this effect. 186This is because there are a variety of processing options that could be 187re-enabled and the correct method is for an application to snapshot the 188current terminal state using the function 189.Fn tcgetattr , 190setting raw mode with 191.Fn cfmakeraw 192and the subsequent 193.Fn tcsetattr , 194and then using another 195.Fn tcsetattr 196with the saved state to revert to the previous terminal state. 197.Pp 198The 199.Fn tcgetattr 200function copies the parameters associated with the terminal referenced 201by 202.Fa fd 203in the termios structure referenced by 204.Fa tp . 205This function is allowed from a background process, however, the terminal 206attributes may be subsequently changed by a foreground process. 207.Pp 208The 209.Fn tcsetattr 210function sets the parameters associated with the terminal from the 211termios structure referenced by 212.Fa tp . 213The 214.Fa action 215field is created by 216.Em or Ns 'ing 217the following values, as specified in the include file 218.Aq Pa termios.h . 219.Bl -tag -width "TCSADRAIN" 220.It Fa TCSANOW 221The change occurs immediately. 222.It Fa TCSADRAIN 223The change occurs after all output written to 224.Fa fd 225has been transmitted to the terminal. 226This value of 227.Fa action 228should be used when changing parameters that affect output. 229.It Fa TCSAFLUSH 230The change occurs after all output written to 231.Fa fd 232has been transmitted to the terminal. 233Additionally, any input that has been received but not read is discarded. 234.It Fa TCSASOFT 235If this value is 236.Em or Ns 'ed 237into the 238.Fa action 239value, the values of the 240.Em c_cflag , 241.Em c_ispeed , 242and 243.Em c_ospeed 244fields are ignored. 245.El 246.Pp 247The 0 baud rate is used to terminate the connection. 248If 0 is specified as the output speed to the function 249.Fn tcsetattr , 250modem control will no longer be asserted on the terminal, disconnecting 251the terminal. 252.Pp 253If zero is specified as the input speed to the function 254.Fn tcsetattr , 255the input baud rate will be set to the same value as that specified by 256the output baud rate. 257.Pp 258If 259.Fn tcsetattr 260is unable to make any of the requested changes, it returns -1 and 261sets errno. 262Otherwise, it makes all of the requested changes it can. 263If the specified input and output baud rates differ and are a combination 264that is not supported, neither baud rate is changed. 265.Pp 266Upon successful completion, the functions 267.Fn tcgetattr 268and 269.Fn tcsetattr 270return a value of 0. 271Otherwise, they 272return -1 and the global variable 273.Va errno 274is set to indicate the error, as follows: 275.Bl -tag -width Er 276.It Bq Er EBADF 277The 278.Fa fd 279argument to 280.Fn tcgetattr 281or 282.Fn tcsetattr 283was not a valid file descriptor. 284.It Bq Er EINTR 285The 286.Fn tcsetattr 287function was interrupted by a signal. 288.It Bq Er EINVAL 289The 290.Fa action 291argument to the 292.Fn tcsetattr 293function was not valid, or an attempt was made to change an attribute 294represented in the termios structure to an unsupported value. 295.It Bq Er ENOTTY 296The file associated with the 297.Fa fd 298argument to 299.Fn tcgetattr 300or 301.Fn tcsetattr 302is not a terminal. 303.El 304.Sh SEE ALSO 305.Xr tcsendbreak 3 , 306.Xr termios 4 307.Sh STANDARDS 308The 309.Fn cfgetispeed , 310.Fn cfsetispeed , 311.Fn cfgetospeed , 312.Fn cfsetospeed , 313.Fn tcgetattr 314and 315.Fn tcsetattr 316functions are expected to be compliant with the 317.St -p1003.1-88 318specification. 319The 320.Fn cfmakeraw 321and 322.Fn cfsetspeed 323functions, 324as well as the 325.Li TCSASOFT 326option to the 327.Fn tcsetattr 328function are extensions to the 329.St -p1003.1-88 330specification. 331