debian man page for tty

TTY(4)							     Linux Programmer's Manual							    TTY(4)

NAME
       tty - controlling terminal

DESCRIPTION
       The  file /dev/tty is a character file with major number 5 and minor number 0, usually of mode 0666 and owner.group root.tty.  It is a syn-
       onym for the controlling terminal of a process, if any.

       In addition to the ioctl(2) requests supported by the device that tty refers to, the ioctl(2) request TIOCNOTTY is supported.

   TIOCNOTTY
       Detach the calling process from its controlling terminal.

       If the process is the session leader, then SIGHUP and SIGCONT signals are sent to the foreground process group and  all	processes  in  the
       current session lose their controlling tty.

       This ioctl(2) call only works on file descriptors connected to /dev/tty.  It is used by daemon processes when they are invoked by a user at
       a terminal.  The process attempts to open /dev/tty.  If the open succeeds, it detaches itself from the terminal by using  TIOCNOTTY,  while
       if the open fails, it is obviously not attached to a terminal and does not need to detach itself.

FILES
       /dev/tty

SEE ALSO
       chown(1), mknod(1), ioctl(2), termios(3), console(4), tty_ioctl(4), ttyS(4), agetty(8), mingetty(8)

COLOPHON
       This  page is part of release 3.44 of the Linux man-pages project.  A description of the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.

Linux								    2003-04-07								    TTY(4)