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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.\" $FreeBSD: src/lib/libc/gen/tcsetattr.3,v 1.6.2.4 2002/12/29 16:35:34 schweikh Exp $ 34.\" 35.Dd January 2, 1994 36.Dt TCSETATTR 3 37.Os 38.Sh NAME 39.Nm cfgetispeed , 40.Nm cfsetispeed , 41.Nm cfgetospeed , 42.Nm cfsetospeed , 43.Nm cfsetspeed , 44.Nm cfmakeraw , 45.Nm tcgetattr , 46.Nm tcsetattr 47.Nd manipulating the termios structure 48.Sh LIBRARY 49.Lb libc 50.Sh SYNOPSIS 51.In termios.h 52.Ft speed_t 53.Fn cfgetispeed "const struct termios *t" 54.Ft int 55.Fn cfsetispeed "struct termios *t" "speed_t speed" 56.Ft speed_t 57.Fn cfgetospeed "const struct termios *t" 58.Ft int 59.Fn cfsetospeed "struct termios *t" "speed_t speed" 60.Ft int 61.Fn cfsetspeed "struct termios *t" "speed_t speed" 62.Ft void 63.Fn cfmakeraw "struct termios *t" 64.Ft int 65.Fn tcgetattr "int fd" "struct termios *t" 66.Ft int 67.Fn tcsetattr "int fd" "int action" "const struct termios *t" 68.Sh DESCRIPTION 69The 70.Fn cfmakeraw , 71.Fn tcgetattr 72and 73.Fn tcsetattr 74functions are provided for getting and setting the termios structure. 75.Pp 76The 77.Fn cfgetispeed , 78.Fn cfsetispeed , 79.Fn cfgetospeed , 80.Fn cfsetospeed 81and 82.Fn cfsetspeed 83functions are provided for getting and setting the baud rate values in 84the termios structure. 85The effects of the functions on the terminal as described below 86do not become effective, nor are all errors detected, until the 87.Fn tcsetattr 88function is called. 89Certain values for baud rates set in the termios structure and passed to 90.Fn tcsetattr 91have special meanings. 92These are discussed in the portion of the manual page that describes the 93.Fn tcsetattr 94function. 95.Sh GETTING AND SETTING THE BAUD RATE 96The input and output baud rates are found in the termios structure. 97The unsigned integer 98.Li speed_t 99is typedef'd in the include file 100.Aq Pa termios.h . 101The value of the integer corresponds directly to the baud rate being 102represented, however, the following symbolic values are defined. 103.Bd -literal 104#define B0 0 105#define B50 50 106#define B75 75 107#define B110 110 108#define B134 134 109#define B150 150 110#define B200 200 111#define B300 300 112#define B600 600 113#define B1200 1200 114#define B1800 1800 115#define B2400 2400 116#define B4800 4800 117#define B9600 9600 118#define B19200 19200 119#define B38400 38400 120#ifndef _POSIX_SOURCE 121#define EXTA 19200 122#define EXTB 38400 123#endif /*_POSIX_SOURCE */ 124.Ed 125.Pp 126The 127.Fn cfgetispeed 128function returns the input baud rate in the termios structure referenced by 129.Fa tp . 130.Pp 131The 132.Fn cfsetispeed 133function sets the input baud rate in the termios structure referenced by 134.Fa tp 135to 136.Fa speed . 137.Pp 138The 139.Fn cfgetospeed 140function returns the output baud rate in the termios structure referenced by 141.Fa tp . 142.Pp 143The 144.Fn cfsetospeed 145function sets the output baud rate in the termios structure referenced by 146.Fa tp 147to 148.Fa speed . 149.Pp 150The 151.Fn cfsetspeed 152function sets both the input and output baud rate in the termios structure 153referenced by 154.Fa tp 155to 156.Fa speed . 157.Pp 158Upon successful completion, the functions 159.Fn cfsetispeed , 160.Fn cfsetospeed , 161and 162.Fn cfsetspeed 163return a value of 0. 164Otherwise, a value of -1 is returned and the global variable 165.Va errno 166is set to indicate the error. 167.Sh GETTING AND SETTING THE TERMIOS STATE 168This section describes the functions that are used to control the general 169terminal interface. 170Unless otherwise noted for a specific command, these functions are restricted 171from use by background processes. 172Attempts to perform these operations shall cause the process group to be sent 173a SIGTTOU signal. 174If the calling process is blocking or ignoring SIGTTOU signals, the process 175is allowed to perform the operation and the SIGTTOU signal is not sent. 176.Pp 177In all the functions, although 178.Fa fd 179is an open file descriptor, the functions affect the underlying terminal 180file, not just the open file description associated with the particular 181file descriptor. 182.Pp 183The 184.Fn cfmakeraw 185function sets the flags stored in the termios structure to a state disabling 186all input and output processing, giving a 187.Dq raw I/O path . 188It should be noted that there is no function to reverse this effect. 189This is because there are a variety of processing options that could be 190re-enabled and the correct method is for an application to snapshot the 191current terminal state using the function 192.Fn tcgetattr , 193setting raw mode with 194.Fn cfmakeraw 195and the subsequent 196.Fn tcsetattr , 197and then using another 198.Fn tcsetattr 199with the saved state to revert to the previous terminal state. 200.Pp 201The 202.Fn tcgetattr 203function copies the parameters associated with the terminal referenced 204by 205.Fa fd 206in the termios structure referenced by 207.Fa tp . 208This function is allowed from a background process, however, the terminal 209attributes may be subsequently changed by a foreground process. 210.Pp 211The 212.Fn tcsetattr 213function sets the parameters associated with the terminal from the 214termios structure referenced by 215.Fa tp . 216The 217.Fa action 218field is created by 219.Em or Ns 'ing 220the following values, as specified in the include file 221.Aq Pa termios.h . 222.Bl -tag -width "TCSADRAIN" 223.It Fa TCSANOW 224The change occurs immediately. 225.It Fa TCSADRAIN 226The change occurs after all output written to 227.Fa fd 228has been transmitted to the terminal. 229This value of 230.Fa action 231should be used when changing parameters that affect output. 232.It Fa TCSAFLUSH 233The change occurs after all output written to 234.Fa fd 235has been transmitted to the terminal. 236Additionally, any input that has been received but not read is discarded. 237.It Fa TCSASOFT 238If this value is 239.Em or Ns 'ed 240into the 241.Fa action 242value, the values of the 243.Em c_cflag , 244.Em c_ispeed , 245and 246.Em c_ospeed 247fields are ignored. 248.El 249.Pp 250The 0 baud rate is used to terminate the connection. 251If 0 is specified as the output speed to the function 252.Fn tcsetattr , 253modem control will no longer be asserted on the terminal, disconnecting 254the terminal. 255.Pp 256If zero is specified as the input speed to the function 257.Fn tcsetattr , 258the input baud rate will be set to the same value as that specified by 259the output baud rate. 260.Pp 261If 262.Fn tcsetattr 263is unable to make any of the requested changes, it returns -1 and 264sets errno. 265Otherwise, it makes all of the requested changes it can. 266If the specified input and output baud rates differ and are a combination 267that is not supported, neither baud rate is changed. 268.Pp 269Upon successful completion, the functions 270.Fn tcgetattr 271and 272.Fn tcsetattr 273return a value of 0. 274Otherwise, they 275return -1 and the global variable 276.Va errno 277is set to indicate the error, as follows: 278.Bl -tag -width Er 279.It Bq Er EBADF 280The 281.Fa fd 282argument to 283.Fn tcgetattr 284or 285.Fn tcsetattr 286was not a valid file descriptor. 287.It Bq Er EINTR 288The 289.Fn tcsetattr 290function was interrupted by a signal. 291.It Bq Er EINVAL 292The 293.Fa action 294argument to the 295.Fn tcsetattr 296function was not valid, or an attempt was made to change an attribute 297represented in the termios structure to an unsupported value. 298.It Bq Er ENOTTY 299The file associated with the 300.Fa fd 301argument to 302.Fn tcgetattr 303or 304.Fn tcsetattr 305is not a terminal. 306.El 307.Sh SEE ALSO 308.Xr tcsendbreak 3 , 309.Xr termios 4 310.Sh STANDARDS 311The 312.Fn cfgetispeed , 313.Fn cfsetispeed , 314.Fn cfgetospeed , 315.Fn cfsetospeed , 316.Fn tcgetattr 317and 318.Fn tcsetattr 319functions are expected to be compliant with the 320.St -p1003.1-88 321specification. 322The 323.Fn cfmakeraw 324and 325.Fn cfsetspeed 326functions, 327as well as the 328.Li TCSASOFT 329option to the 330.Fn tcsetattr 331function are extensions to the 332.St -p1003.1-88 333specification. 334