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The array c_cc specifies the special control-characters that affect the operation of the communication-port and the processing of terminal input and output as described in the ``Special characters'' section below. For each entry of the control-character array c_cc, the following are typical default values:
Terminal device control character array
Subscript value | Subscript name | Character value | Character description |
---|---|---|---|
0 | VINTR | ASCII DEL | INTR character |
1 | VNUIT | ASCII FS | QUIT character |
2 | VERASE | ^h | ERASE character |
3 | VKILL | ^u | KILL character |
4 | VEOF | ASCII EOT | EOF character |
5 | VEOL | ASCII NUL | EOL character |
6 | reserved | ||
7 | reserved | ||
8 | VSTART | ASCII DC1 | START character |
9 | VSTOP | ASCII DC3 | STOP character |
10 | VSUSP | ASCII SUB | SUSP character |
The subscript values are unique, except that the VMIN and VTIME subscripts may have the same value as the VEOF and VEOL subscripts respectively. The <termios.h> header file defines the relative positions, subscript names and default values for the control-character array c_cc (see ``Special control characters'' in termio(7)).
The NL and CR character cannot be changed. The INTR, QUIT, ERASE, KILL, EOF, EOL, SUSP, STOP and START characters can be changed as follows:
struct termios term; term.c_cc[VINTR] = `a'; term.c_cc[VQUIT] = `b'; term.c_cc[VERASE] = `c'; term.c_cc[VKILL] = `d'; term.c_cc[VEOF] = `e'; term.c_cc[VEOL] = `f'; term.c_cc[VSUSP] = `g'; term.c_cc[VSTOP] = `h'; term.c_cc[VSTART] = `i';
where a, b, c, d, e, f, g, h and i are the INTR, QUIT, ERASE, KILL, EOF, EOL, SUSP, STOP and START characters respectively.
Implementations which prohibit changing the START and STOP characters may ignore the character values in the c_cc array indexed by the VSTART and VSTOP subscripts when tcsetattr is called, but return the character value when tcsetattr is called (see tcsetattr in termios(3C)).
If _POSIX_VDISABLE is defined for the terminal-device-file, and the value of one of the changeable special control-characters equals _POSIX_VDISABLE, that function is disabled; that is, the special character is ignored on input and is not recognized (see ``Special characters'' section below). If ICANON is clear, the value of _POSIX_VDISABLE lacks any special meaning for the VMIN and VTIME entries of the c_cc array.