TIOCPKT(2const) — Linux manual page

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | HISTORY | SEE ALSO | COLOPHON

TIOCPKT(2const)                                          TIOCPKT(2const)

NAME         top

       TIOCPKT, TIOCGPKT, TIOCSPTLCK, TIOCGPTLCK, TIOCGPTPEER -
       pseudoterminal ioctls

LIBRARY         top

       Standard C library (libc, -lc)

SYNOPSIS         top

       #include <asm/termbits.h>  /* Definition of TIOC* constants */
       #include <sys/ioctl.h>

       int ioctl(int fd, TIOCPKT, const int *mode);
       int ioctl(int fd, TIOCPKT, int *mode);

       int ioctl(int fd, TIOCSPTLCK, const int *lock);
       int ioctl(int fd, TIOCGPTLCK, int *lock);

       int ioctl(int fd, TIOCGPTPEER, int flags);

DESCRIPTION         top

       TIOCPKT
              Enable (when *mode is nonzero) or disable packet mode.
              Can be applied to the master side of a pseudoterminal only
              (and will return ENOTTY otherwise).  In packet mode, each
              subsequent read(2) will return a packet that either
              contains a single nonzero control byte, or has a single
              byte containing zero ('\0') followed by data written on
              the slave side of the pseudoterminal.  If the first byte
              is not TIOCPKT_DATA (0), it is an OR of one or more of the
              following bits:

              TIOCPKT_FLUSHREAD    The read queue for the
                                   terminal is flushed.
              TIOCPKT_FLUSHWRITE   The write queue for the
                                   terminal is flushed.
              TIOCPKT_STOP         Output to the terminal
                                   is stopped.
              TIOCPKT_START        Output to the terminal
                                   is restarted.
              TIOCPKT_DOSTOP       The start and stop
                                   characters are ^S/^Q.
              TIOCPKT_NOSTOP       The start and stop
                                   characters are not
                                   ^S/^Q.

              While  packet  mode  is  in  use,  the presence of control
              status information to be read from the master side may  be
              detected  by  a  select(2) for exceptional conditions or a
              poll(2) for the POLLPRI event.

              This mode is used by rlogin(1) and rlogind(8) to implement
              a  remote-echoed,  locally  ^S/^Q  flow-controlled  remote
              login.

       TIOCGPKT
              Return the current packet mode setting in the integer
              pointed to by mode.

       TIOCSPTLCK
              Set (if *lock is nonzero) or remove (if *lock is zero) the
              lock on the pseudoterminal slave device.  (See also
              unlockpt(3).)

       TIOCGPTLCK
              Place the current lock state of the pseudoterminal slave
              device in the location pointed to by lock.

       TIOCGPTPEER
              Given a file descriptor in fd that refers to a
              pseudoterminal master, open (with the given open(2)-style
              flags) and return a new file descriptor that refers to the
              peer pseudoterminal slave device.  This operation can be
              performed regardless of whether the pathname of the slave
              device is accessible through the calling process's mount
              namespace.

              Security-conscious programs interacting with namespaces
              may wish to use this operation rather than open(2) with
              the pathname returned by ptsname(3), and similar library
              functions that have insecure APIs.  (For example,
              confusion can occur in some cases using ptsname(3) with a
              pathname where a devpts filesystem has been mounted in a
              different mount namespace.)

RETURN VALUE         top

       On success, 0 is returned.  On error, -1 is returned, and errno
       is set to indicate the error.

ERRORS         top

       ENOTTY

HISTORY         top

       TIOCGPKT
              Linux 3.8.

       TIOCGPTLCK
              Linux 3.8.

       TIOCGPTPEER
              Linux 4.13.

       The BSD ioctls TIOCSTOP, TIOCSTART, TIOCUCNTL, and TIOCREMOTE
       have not been implemented under Linux.

SEE ALSO         top

       ioctl(2), ioctl_tty(2)

COLOPHON         top

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Linux man-pages 6.9.1          2024-06-15                TIOCPKT(2const)

Pages that refer to this page: ioctl_tty(2)