.\" Copyright (c) 1983 Regents of the University of California.
.\" All rights reserved. The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution.
.\" @(#)pty.4 5.1 (Berkeley) %G%
pty \- pseudo terminal driver
driver provides support for a device-pair termed a
A pseudo terminal is a pair of character devices, a
device. The slave device provides processes
However, whereas all other devices which provide the
have a hardware device of some sort behind them, the slave
device has, instead, another process manipulating
it through the master half of the pseudo terminal.
That is, anything written on the master device is
given to the slave device as input and anything written
on the slave device is presented as input on the master
In configuring, if no optional ``count'' is given in
the specification, 16 pseudo terminal pairs are configured.
calls apply only to pseudo terminals:
Stops output to a terminal (e.g. like typing ^S). Takes
Restarts output (stopped by TIOCSTOP or by typing ^S).
mode. Packet mode is enabled by specifying (by reference)
a nonzero parameter and disabled by specifying (by reference)
a zero parameter. When applied to the master side of a pseudo
terminal, each subsequent
from the terminal will return data written on the slave part of
the pseudo terminal preceded by a zero byte (symbolically
defined as TIOCPKT_DATA), or a single byte reflecting control
status information. In the latter case, the byte is an inclusive-or
of zero or more of the bits:
whenever the read queue for the terminal is flushed.
whenever the write queue for the terminal is flushed.
whenever output to the terminal is stopped a la ^S.
whenever output to the terminal is restarted.
whenever the start and stop characters are not ^S/^Q.
to implement a remote-echoed, locally ^S/^Q flow-controlled
remote login with proper back-flushing of output; it can be
used by other similar programs.
A mode for the master half of a pseudo terminal, independent
of TIOCPKT. This mode causes input to the pseudo terminal
to be flow controlled and not input edited (regardless of the
terminal mode). Each write to the control terminal produces
a record boundary for the process reading the terminal. In
normal usage, a write of data is like the data typed as a line
on the terminal; a write of 0 bytes is like typing an end-of-file
character. TIOCREMOTE can be used when doing remote line
editing in a window manager, or whenever flow controlled input
/dev/pty[p-r][0-9a-f] master pseudo terminals
/dev/tty[p-r][0-9a-f] slave pseudo terminals
It is not possible to send an EOT.