tty (4)


       tty - controlling terminal


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

       In  addition  to  the ioctl() requests supported by the device that tty
       refers to, the following ioctl() request is supported:

              Detach the current process from its  controlling  terminal,  and
              remove  it  from its current process group, without attaching it
              to a new process group (that is, set its  process  group  ID  to
              zero).   This  ioctl()  call only works on file descriptors con-
              nected to /dev/tty; this 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




       mknod(1), chown(1), getty(1), termios(3), console(4), ttys(4)

Linux                             1992-01-21                            tty(4)