tcgetattr()

get the current terminal control settings

Synopsis:

#include <termios.h>
int tcgetattr( int fildes,
               struct termios *termios_p );

Description:

The tcgetattr() function gets the current terminal control settings for the opened device indicated by fildes, and stores the results in the structure pointed to by termios_p.

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.

PARENB

Parity enable.

PARODD

Odd parity, else even.

The following bits will also have effect within the c_cflag member if the IEXTEN bit of c_lflag is set:

PARSTK

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

IHFLOW

Support input flow control using the hardware handshaking lines.

OHFLOW

Support output flow control using the hardware handshaking lines.

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[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 will only be acted on if they are 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.

You should use the dev_mode() function in situations where only the principal terminal modes (ECHO, ISIG, ICANON and OPOST) are being affected.

Returns:

0

Success

-1

An error occurred. errno is set to indicate the error.

Errors:

EBADF

The fildes argument is invalid.

ENOSYS

The resource manager associated with fildes doesn't support this call.

ENOTTY

The fildes argument doesn't refer to a terminal device.

Examples:

See tcsetattr().

Classification:

POSIX 1003.1

See also:

dev_mode(), errno, fpathconf(), tcsetattr()

Chapter 7 of POSIX 1003.1