4.3BSD - /usr/man/cat2/vhangup.0

VHANGUP(2)                                                          VHANGUP(2)


NAME
       vhangup - virtually ‘‘hangup’’ the current control terminal

SYNOPSIS
       vhangup()

DESCRIPTION
       Vhangup is used by the initialization process init(8) (among others) to
       arrange that users are given “clean”’ terminals at login,  by  revoking
       access  of  the  previous  users’ processes to the terminal.  To effect
       this, vhangup searches the system tables for references to the  control
       terminal  of  the invoking process, revoking access permissions on each
       instance of the terminal that it finds.  Further attempts to access the
       terminal  by  the  affected  processes  will  yield i/o errors (EBADF).
       Finally, a hangup signal (SIGHUP) is sent to the process group  of  the
       control terminal.

SEE ALSO
       init (8)

BUGS
       Access to the control terminal via /dev/tty is still possible.

       This call should be replaced by an automatic mechanism that takes place
       on process exit.


4th Berkeley Distribution        June 30, 1985                      VHANGUP(2)