termios

Terminal control structure

Synopsis:

struct termios {
    tcflag_t        c_iflag;
    tcflag_t        c_oflag;
    tcflag_t        c_cflag;
    tcflag_t        c_lflag;
    cc_t            c_cc[NCCS];
    uint32_t        reserved[3];
    speed_t         c_ispeed;
    speed_t         c_ospeed;
};

Description:

The termios control structure is defined in <termios.h>, and contains at least the members described below.

tcflag_t c_iflag

Input modes. This member contains at least the following bits:

BRKINT

Signal interrupt on break.

ICRNL

Map CR to NL on input.

IGNBRK

Ignore break conditions.

IGNCR

Ignore CR.

IGNPAR

Ignore characters with parity errors.

INLCR

Map NL to CR on input.

INPCK

Enable input parity check.

ISTRIP

Strip top bit from character.

IXOFF

Enable software input flow control (via START/STOP chars).

IXON

Enable software output flow control (via START/STOP chars).

PARMRK

Mark parity errors in the input data stream.

tcflag_t c_oflag

Output modes. This member contains at least the following bits:

OPOST

Perform output processing.

tcflag_t c_cflag

Control modes. This member contains at least the following bits:

CLOCAL

Ignore modem status lines.

CREAD

Enable receiver.

CSIZE

Number of data bits per character.

CS5

5 data bits.

CS6

6 data bits.

CS7

7 data bits.

CS8

8 data bits.

CSTOPB

Two stop bits, else one.

HUPCL

Hang up on last close.

IHFLOW

Support input flow control using the hardware handshaking lines.

OHFLOW

Support output flow control using the hardware handshaking lines.

PARENB

Parity enable.

PARODD

Odd parity, else even.

PARSTK

Stick parity (mark parity if PARODD is set, else space parity).

tcflag_t c_lflag

Local modes. This member contains at least the following bits:

ECHO

Enable echo.

ECHOE

Echo ERASE as destructive backspace.

ECHOK

Echo KILL as a line erase.

ECHONL

Echo '\n', even if ECHO is off.

ICANON

Canonical input mode (line editing enabled).

IEXTEN

QNX extensions to POSIX are enabled.

ISIG

Enable signals.

NOFLSH

Disable flush after interrupt, quit, or suspend.

TOSTOP

Send SIGTTOU for background output.

cc_t c_cc[NCCS]

Control characters. The array c_cc includes at least the following control characters:

c_cc[VEOF]

EOF character.

c_cc[VEOL]

EOL character.

c_cc[VERASE]

ERASE character.

c_cc[VFWD]

FORWARD character.

c_cc[VINTR]

INTR character.

c_cc[VKILL]

KILL character.

c_cc[VMIN]

MIN value.

c_cc[VQUIT]

QUIT character.

c_cc[VSUSP]

SUSP character.

c_cc[VTIME]

TIME value.

c_cc[VSTART]

START character.

c_cc[VSTOP]

STOP character.

The following control characters are also defined, but are only acted on if they're immediately preceded by the nonzero characters in c_cc[VPREFIX][4], and are immediately followed by the nonzero characters in c_cc[VSUFFIX][4] and the IEXTEN bit of c_lflag is set:

c_cc[VLEFT]

Left cursor motion.

c_cc[VRIGHT]

Right cursor motion.

c_cc[VUP]

Up cursor motion.

c_cc[VDOWN]

Down cursor motion.

c_cc[VINS]

Insert character.

c_cc[VDEL]

Delete character.

c_cc[VRUB]

Rubout character.

c_cc[VCAN]

Cancel character.

c_cc[VHOME]

Home character.

c_cc[VEND]

End character.

Any of the control characters in the c_cc array can be disabled by setting that character to the _PC_VDISABLE parameter which is returned by fpathconf() (typically a zero).

speed_t c_ispeed

Input baud rate. This member should be queried and set with the cfgetispeed() and cfsetispeed() functions.

speed_t c_ospeed

Output baud rate. This member should be queried and set with the cfgetospeed() and cfsetospeed() functions.

Classification:

POSIX 1003.1

See also:

cfgetispeed(), cfgetospeed(), cfsetispeed(), cfsetospeed(), cfmakeraw(), fpathconf(), forkpty(), openpty(), pathconf(), readcond(), tcgetattr(), tcsetattr()