pty(4) — UTek 4.0



PTY(4)                  COMMAND REFERENCE                  PTY(4)



NAME
     pty - pseudo terminal driver

SYNOPSIS
     #include <sys/ioctl.h>

DESCRIPTION
     The pty driver provides support for a device-pair termed a
     pseudo terminal.  A pseudo terminal is a pair of character
     devices, a master device and a slave device.  The slave
     device provides processes an interface identical to that
     described in tty(4).  However, whereas all other devices
     which provide the interface described in tty(4) 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 device.

     The following ioctl calls apply only to pseudo terminals:

     TIOCPKT   Enable/disable packet 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
               read 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:

               TIOCPKT_FLUSHREAD      whenever the read queue for
                                      the terminal is flushed.

               TIOCPKT_FLUSHWRITE     whenever the write queue
                                      for the terminal is
                                      flushed.

               TIOCPKT_STOP           whenever output to the
                                      terminal is stopped a la
                                      ^S.

               TIOCPKT_START          whenever output to the
                                      terminal is restarted.

               TIOCPKT_DOSTOP         whenever t_stopc is ^S and
                                      t_startc is ^Q.

               TIOCPKT_NOSTOP         whenever the start and stop



Printed 4/6/89                                                  1



PTY(4)                  COMMAND REFERENCE                  PTY(4)



                                      characters are not ^S/^Q.

               This mode is used by rlogin(1n) and rlogind(8n) 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.

     TIOCREMOTE
               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 is required.

FILES
     /dev/pty*    master pseudo terminals

     /dev/ttyp*   slave pseudo terminals

DIAGNOSTICS
     None.

CAVEATS
     It is not possible to send an EOT.























Printed 4/6/89                                                  2

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sy:296,328;
de:624,2522;3434,1130;
fi:4564,171;
di:4735,134;
ca:4869,138;
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