termios -- Overview

POSIX extended terminal interface

The name termios describes a  group of routines that POSIX Standard defines
to  extend  the  termio  interface  to  terminals.   termios  includes  the
following routines:

cfgetispeed()..Get input speed
cfgetospeed()..Get output speed
cfsetispeed()..Set input speed
cfsetospeed()..Set output speed
tcdrain()......Drain output to a device
tcflow().......Control flow on a terminal device
tcflush()......Flush data being exchanged with a terminal
tcgetattr()....Get terminal attributes
tcsendbreak()..Send a break to a terminal
tcsetattr()....Set terminal attributes

Each  is described  in  its own  Lexicon  entry.  Under  COHERENT, all  are
defined as macros in header file <termios.h>.

Example

The following example returns the  input and output speeds for the terminal
device that you now are using:

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <termios.h>

int main()
{
    struct termios term;
    int speed;

    if (tcgetattr(STDIN_FILENO, &term) < 0) {
        fprintf(stderr, "tcgetattr error");
        exit(EXIT_FAILURE);
    }

    speed = cfgetispeed(&term);
    printf("tty line input speed is ");

    if      (speed == B50)      printf("50 baud\n");
    else if (speed == B75)      printf("75 baud\n");
    else if (speed == B110)     printf("110 baud\n");
    else if (speed == B134)     printf("134 baud\n");
    else if (speed == B150)     printf("150 baud\n");
    else if (speed == B200)     printf("200 baud\n");
    else if (speed == B300)     printf("300 baud\n");
    else if (speed == B600)     printf("600 baud\n");
    else if (speed == B1200)    printf("1200 baud\n");
    else if (speed == B1800)    printf("1800 baud\n");
    else if (speed == B2400)    printf("2400 baud\n");
    else if (speed == B4800)    printf("4800 baud\n");
    else if (speed == B9600)    printf("9600 baud\n");
    else if (speed == B19200)   printf("19200 baud\n");
    else if (speed == B38400)   printf("38400 baud\n");
    else                printf("unknown speed\n");

    speed = cfgetospeed(&term);
    printf("tty line output speed is ");

    if      (speed == B50)      printf("50 baud\n");
    else if (speed == B75)      printf("75 baud\n");
    else if (speed == B110)     printf("110 baud\n");
    else if (speed == B134)     printf("134 baud\n");
    else if (speed == B150)     printf("150 baud\n");
    else if (speed == B200)     printf("200 baud\n");
    else if (speed == B300)     printf("300 baud\n");
    else if (speed == B600)     printf("600 baud\n");
    else if (speed == B1200)    printf("1200 baud\n");
    else if (speed == B1800)    printf("1800 baud\n");
    else if (speed == B2400)    printf("2400 baud\n");
    else if (speed == B4800)    printf("4800 baud\n");
    else if (speed == B9600)    printf("9600 baud\n");
    else if (speed == B19200)   printf("19200 baud\n");
    else if (speed == B38400)   printf("38400 baud\n");
    else                printf("unknown speed\n");

    exit(EXIT_SUCCESS);
}

See Also

cfgetispeed(),
cfgetospeed(),
cfsetispeed(),
cfsetospeed(),
Programming COHERENT,
tcdrain(),
tcflow(),
tcflush(),
tcgetattr(),
tcsendbreak(),
tcsetattr(),
termio,
termios.h

Notes

If a program that uses termios  has set the termio flag ISIG (which enables
signals) and  receives character  SUSP (normally <ctrl-Z>),  it sends
the signal SIGTSTP to the  current process group.  By default, termios then
discards  SUSP. Character  SUSP, as  its name implies,  tells a  program to
suspend operation and recede into the background.  Please note that because
COHERENT does not yet support job control, SUSP at present will do nothing.

© 2012 by Stephen A. Ness