Overview

Well, i am writing this because sometimes there is a need to change the speed of the terminal dsession to match that of the device it is connected to.
Okay, well, does it sound a bit too technical?

Let me sum it up quickly.

Terminal devices can run into different states i.e, canonical mode/cooked mode or noncanonical mode/raw mode. In the former state, the terminal driver returns one line of data at a time and in the later, the terminal device returns one char at a time without assembling lines of data.
The third state is the the cbreak mode, it is similar to raw mode but in this a signal is raised for the special characters.
Ever used vi? Well, it uses raw mode for i/o.

Moving on

There is a struct named termios that has all the attributes controlling the terminal device.

	struct termios {
tcflag_t c_iflag; /*input*/
tcflag_t c_oflag; /*output*/
tcflag_t c_cflag; /*control flag*/
tcflag_t c_lflag; /*local flag*/
cc_t c_cc[NCCS]; /*control chars*/
};

The above mentioned structure is used with two functions mainly,

	#include <termios.h>
int tcgetattr(int filedes, struct termios *termptr); //Gets the current state of the terminal with open file descriptor filedes.
int tcsetattr(int filedes, int opt, const struct termios *termptr); //Set the attributes for the terminal.
/*Return error if the *filedes* argument is not associated with the terminal device.
The argument opt specifies when the changes are to take place.
*/

So those who are interested in developing a terminal based editor, they might be interested in reading more on terminal I/O.



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