plucky (2) TIOCSPTLCK.2const.gz

NAME

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

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #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

       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

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

ERRORS

       ENOTTY

HISTORY

       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

       ioctl(2), ioctl_tty(2)