tty

NAME

SYNOPSIS

DESCRIPTION

Terminal Special Files

Terminal File Operations

	int pgrp; 
 
	pgrp = getpgrp(); 
	ioctl(0, TIOCSPGRP, &pgrp);

Terminal File Request Descriptions

TIOCSETD int *ldisc

This call is obsolete but left for compatibility. Before FreeBSD 8.0, it would change to the new line discipline pointed to by ldisc.

TIOCGETD int *ldisc

Return the current line discipline in the integer pointed to by ldisc.

TIOCSBRK void

Set the terminal hardware into BREAK condition.

TIOCCBRK void

Clear the terminal hardware BREAK condition.

TIOCSDTR void

Assert data terminal ready (DTR).

TIOCCDTR void

Clear data terminal ready (DTR).

TIOCGPGRP int *tpgrp

Return the current process group with which the terminal is associated in the integer pointed to by tpgrp. This is the underlying call that implements the termios(4) tcgetattr() call.

TIOCSPGRP int *tpgrp

Associate the terminal with the process group (as an integer) pointed to by tpgrp. This is the underlying call that implements the termios(4) tcsetattr() call.

TIOCGETA struct termios *term

Place the current value of the termios state associated with the device in the termios structure pointed to by term. This is the underlying call that implements the termios(4) tcgetattr() call.

TIOCSETA struct termios *term

Set the termios state associated with the device immediately. This is the underlying call that implements the termios(4) tcsetattr() call with the TCSANOW option.

TIOCSETAW struct termios *term

First wait for any output to complete, then set the termios state associated with the device. This is the underlying call that implements the termios(4) tcsetattr() call with the TCSADRAIN option.

TIOCSETAF struct termios *term

First wait for any output to complete, clear any pending input, then set the termios state associated with the device. This is the underlying call that implements the termios(4) tcsetattr() call with the TCSAFLUSH option.

TIOCOUTQ int *num

Place the current number of characters in the output queue in the integer pointed to by num.

TIOCSTI char *cp

Simulate typed input. Pretend as if the terminal received the character pointed to by cp.

TIOCNOTTY void

In the past, when a process that did not have a controlling terminal (see The Controlling Terminal in termios(4)) first opened a terminal device, it acquired that terminal as its controlling terminal. For some programs this was a hazard as they did not want a controlling terminal in the first place, and this provides a mechanism to disassociate the controlling terminal from the calling process. It must be called by opening the file /dev/tty and calling TIOCNOTTY on that file descriptor.

The current system does not allocate a controlling terminal to a process on an open() call: there is a specific ioctl called TIOCSCTTY to make a terminal the controlling terminal. In addition, a program can fork() and call the setsid() system call which will place the process into its own session - which has the effect of disassociating it from the controlling terminal. This is the new and preferred method for programs to lose their controlling terminal.

However, environmental restrictions may prohibit the process from being able to fork() and call the setsid() system call to disassociate it from the controlling terminal. In this case, it must use TIOCNOTTY.

TIOCSTOP void

Stop output on the terminal (like typing ^S at the keyboard).

TIOCSTART void

Start output on the terminal (like typing ^Q at the keyboard).

TIOCSCTTY void

Make the terminal the controlling terminal for the process (the process must not currently have a controlling terminal).

TIOCDRAIN void

Wait until all output is drained, or until the drain wait timeout expires.

TIOCGDRAINWAIT int *timeout

Return the current drain wait timeout in seconds.

TIOCSDRAINWAIT int *timeout

Set the drain wait timeout in seconds. A value of zero disables timeouts. The default drain wait timeout is controlled by the tunable sysctl(8) OID kern.tty_drainwait.

TIOCEXCL void

Set exclusive use on the terminal. No further opens are permitted except by root. Of course, this means that programs that are run by root (or setuid) will not obey the exclusive setting - which limits the usefulness of this feature.

TIOCNXCL void

Clear exclusive use of the terminal. Further opens are permitted.

TIOCFLUSH int *what

If the value of the int pointed to by what contains the FREAD bit as defined in <sys/file.h>, then all characters in the input queue are cleared. If it contains the FWRITE bit, then all characters in the output queue are cleared. If the value of the integer is zero, then it behaves as if both the FREAD and FWRITE bits were set (i.e., clears both queues).

TIOCGWINSZ struct winsize *ws

Put the window size information associated with the terminal in the winsize structure pointed to by ws. The window size structure contains the number of rows and columns (and pixels if appropriate) of the devices attached to the terminal. It is set by user software and is the means by which most full-screen oriented programs determine the screen size. The winsize structure is defined in <sys/ioctl.h>.

TIOCSWINSZ struct winsize *ws

Set the window size associated with the terminal to be the value in the winsize structure pointed to by ws (see above).

TIOCCONS int *on

If on points to a non-zero integer, redirect kernel console output (kernel printf's) to this terminal. If on points to a zero integer, redirect kernel console output back to the normal console. This is usually used on workstations to redirect kernel messages to a particular window.

TIOCMSET int *state

The integer pointed to by state contains bits that correspond to modem state. Following is a list of defined variables and the modem state they represent:

TIOCM_LE

Line Enable.

TIOCM_DTR

Data Terminal Ready.

TIOCM_RTS

Request To Send.

TIOCM_ST

Secondary Transmit.

TIOCM_SR

Secondary Receive.

TIOCM_CTS

Clear To Send.

TIOCM_CAR

Carrier Detect.

TIOCM_CD

Carrier Detect (synonym).

TIOCM_RNG

Ring Indication.

TIOCM_RI

Ring Indication (synonym).

TIOCM_DSR

Data Set Ready.

This call sets the terminal modem state to that represented by state. Not all terminals may support this.

TIOCMGET int *state

Return the current state of the terminal modem lines as represented above in the integer pointed to by state.

TIOCMBIS int *state

The bits in the integer pointed to by state represent modem state as described above, however the state is OR-ed in with the current state.

TIOCMBIC int *state

The bits in the integer pointed to by state represent modem state as described above, however each bit which is on in state is cleared in the terminal.

IMPLEMENTATION NOTES

SEE ALSO