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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.\" $DragonFly: src/lib/libc/gen/tcsetattr.3,v 1.4 2007/06/30 19:03:52 swildner Exp $ 35.\" 36.Dd January 2, 1994 37.Dt TCSETATTR 3 38.Os 39.Sh NAME 40.Nm cfgetispeed , 41.Nm cfsetispeed , 42.Nm cfgetospeed , 43.Nm cfsetospeed , 44.Nm cfsetspeed , 45.Nm cfmakeraw , 46.Nm tcgetattr , 47.Nm tcsetattr 48.Nd manipulating the termios structure 49.Sh LIBRARY 50.Lb libc 51.Sh SYNOPSIS 52.In termios.h 53.Ft speed_t 54.Fn cfgetispeed "const struct termios *t" 55.Ft int 56.Fn cfsetispeed "struct termios *t" "speed_t speed" 57.Ft speed_t 58.Fn cfgetospeed "const struct termios *t" 59.Ft int 60.Fn cfsetospeed "struct termios *t" "speed_t speed" 61.Ft int 62.Fn cfsetspeed "struct termios *t" "speed_t speed" 63.Ft void 64.Fn cfmakeraw "struct termios *t" 65.Ft int 66.Fn tcgetattr "int fd" "struct termios *t" 67.Ft int 68.Fn tcsetattr "int fd" "int action" "const struct termios *t" 69.Sh DESCRIPTION 70The 71.Fn cfmakeraw , 72.Fn tcgetattr 73and 74.Fn tcsetattr 75functions are provided for getting and setting the termios structure. 76.Pp 77The 78.Fn cfgetispeed , 79.Fn cfsetispeed , 80.Fn cfgetospeed , 81.Fn cfsetospeed 82and 83.Fn cfsetspeed 84functions are provided for getting and setting the baud rate values in 85the termios structure. 86The effects of the functions on the terminal as described below 87do not become effective, nor are all errors detected, until the 88.Fn tcsetattr 89function is called. 90Certain values for baud rates set in the termios structure and passed to 91.Fn tcsetattr 92have special meanings. 93These are discussed in the portion of the manual page that describes the 94.Fn tcsetattr 95function. 96.Sh GETTING AND SETTING THE BAUD RATE 97The input and output baud rates are found in the termios structure. 98The unsigned integer 99.Li speed_t 100is typedef'd in the include file 101.In termios.h . 102The value of the integer corresponds directly to the baud rate being 103represented, however, the following symbolic values are defined. 104.Bd -literal 105#define B0 0 106#define B50 50 107#define B75 75 108#define B110 110 109#define B134 134 110#define B150 150 111#define B200 200 112#define B300 300 113#define B600 600 114#define B1200 1200 115#define B1800 1800 116#define B2400 2400 117#define B4800 4800 118#define B9600 9600 119#define B19200 19200 120#define B38400 38400 121#ifndef _POSIX_SOURCE 122#define EXTA 19200 123#define EXTB 38400 124#endif /*_POSIX_SOURCE */ 125.Ed 126.Pp 127The 128.Fn cfgetispeed 129function returns the input baud rate in the termios structure referenced by 130.Fa tp . 131.Pp 132The 133.Fn cfsetispeed 134function sets the input baud rate in the termios structure referenced by 135.Fa tp 136to 137.Fa speed . 138.Pp 139The 140.Fn cfgetospeed 141function returns the output baud rate in the termios structure referenced by 142.Fa tp . 143.Pp 144The 145.Fn cfsetospeed 146function sets the output baud rate in the termios structure referenced by 147.Fa tp 148to 149.Fa speed . 150.Pp 151The 152.Fn cfsetspeed 153function sets both the input and output baud rate in the termios structure 154referenced by 155.Fa tp 156to 157.Fa speed . 158.Pp 159Upon successful completion, the functions 160.Fn cfsetispeed , 161.Fn cfsetospeed , 162and 163.Fn cfsetspeed 164return a value of 0. 165Otherwise, a value of -1 is returned and the global variable 166.Va errno 167is set to indicate the error. 168.Sh GETTING AND SETTING THE TERMIOS STATE 169This section describes the functions that are used to control the general 170terminal interface. 171Unless otherwise noted for a specific command, these functions are restricted 172from use by background processes. 173Attempts to perform these operations shall cause the process group to be sent 174a SIGTTOU signal. 175If the calling process is blocking or ignoring SIGTTOU signals, the process 176is allowed to perform the operation and the SIGTTOU signal is not sent. 177.Pp 178In all the functions, although 179.Fa fd 180is an open file descriptor, the functions affect the underlying terminal 181file, not just the open file description associated with the particular 182file descriptor. 183.Pp 184The 185.Fn cfmakeraw 186function sets the flags stored in the termios structure to a state disabling 187all input and output processing, giving a 188.Dq raw I/O path . 189It should be noted that there is no function to reverse this effect. 190This is because there are a variety of processing options that could be 191re-enabled and the correct method is for an application to snapshot the 192current terminal state using the function 193.Fn tcgetattr , 194setting raw mode with 195.Fn cfmakeraw 196and the subsequent 197.Fn tcsetattr , 198and then using another 199.Fn tcsetattr 200with the saved state to revert to the previous terminal state. 201.Pp 202The 203.Fn tcgetattr 204function copies the parameters associated with the terminal referenced 205by 206.Fa fd 207in the termios structure referenced by 208.Fa tp . 209This function is allowed from a background process, however, the terminal 210attributes may be subsequently changed by a foreground process. 211.Pp 212The 213.Fn tcsetattr 214function sets the parameters associated with the terminal from the 215termios structure referenced by 216.Fa tp . 217The 218.Fa action 219field is created by 220.Em or Ns 'ing 221the following values, as specified in the include file 222.In termios.h . 223.Bl -tag -width "TCSADRAIN" 224.It Fa TCSANOW 225The change occurs immediately. 226.It Fa TCSADRAIN 227The change occurs after all output written to 228.Fa fd 229has been transmitted to the terminal. 230This value of 231.Fa action 232should be used when changing parameters that affect output. 233.It Fa TCSAFLUSH 234The change occurs after all output written to 235.Fa fd 236has been transmitted to the terminal. 237Additionally, any input that has been received but not read is discarded. 238.It Fa TCSASOFT 239If this value is 240.Em or Ns 'ed 241into the 242.Fa action 243value, the values of the 244.Em c_cflag , 245.Em c_ispeed , 246and 247.Em c_ospeed 248fields are ignored. 249.El 250.Pp 251The 0 baud rate is used to terminate the connection. 252If 0 is specified as the output speed to the function 253.Fn tcsetattr , 254modem control will no longer be asserted on the terminal, disconnecting 255the terminal. 256.Pp 257If zero is specified as the input speed to the function 258.Fn tcsetattr , 259the input baud rate will be set to the same value as that specified by 260the output baud rate. 261.Pp 262If 263.Fn tcsetattr 264is unable to make any of the requested changes, it returns -1 and 265sets 266.Va errno . 267Otherwise, it makes all of the requested changes it can. 268If the specified input and output baud rates differ and are a combination 269that is not supported, neither baud rate is changed. 270.Pp 271Upon successful completion, the functions 272.Fn tcgetattr 273and 274.Fn tcsetattr 275return a value of 0. 276Otherwise, they 277return -1 and the global variable 278.Va errno 279is set to indicate the error, as follows: 280.Bl -tag -width Er 281.It Bq Er EBADF 282The 283.Fa fd 284argument to 285.Fn tcgetattr 286or 287.Fn tcsetattr 288was not a valid file descriptor. 289.It Bq Er EINTR 290The 291.Fn tcsetattr 292function was interrupted by a signal. 293.It Bq Er EINVAL 294The 295.Fa action 296argument to the 297.Fn tcsetattr 298function was not valid, or an attempt was made to change an attribute 299represented in the termios structure to an unsupported value. 300.It Bq Er ENOTTY 301The file associated with the 302.Fa fd 303argument to 304.Fn tcgetattr 305or 306.Fn tcsetattr 307is not a terminal. 308.El 309.Sh SEE ALSO 310.Xr tcsendbreak 3 , 311.Xr termios 4 312.Sh STANDARDS 313The 314.Fn cfgetispeed , 315.Fn cfsetispeed , 316.Fn cfgetospeed , 317.Fn cfsetospeed , 318.Fn tcgetattr 319and 320.Fn tcsetattr 321functions are expected to be compliant with the 322.St -p1003.1-88 323specification. 324The 325.Fn cfmakeraw 326and 327.Fn cfsetspeed 328functions, 329as well as the 330.Li TCSASOFT 331option to the 332.Fn tcsetattr 333function are extensions to the 334.St -p1003.1-88 335specification. 336