VHANGUP(2) System Calls Manual VHANGUP(2)
vhangup - virtually ``hangup'' the current control terminal
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 affect
this, vhangup() searches the system tables for references to the con-
trol 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 SIGHUP (hangup signal) is sent to the process
group of the control terminal.
Access to the control terminal using /dev/tty is still possible.
This call should be replaced by an automatic mechanism that takes place
on process exit.
21 January 1990 VHANGUP(2)