vhangup(2) — 4 BSD
NAME
vhangup − virtually ”hangup” the current control terminal
SYNOPSIS
vhangup()
DESCRIPTION
vhangup arranges 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 which 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.
BUGS
Access to the control terminal via /dev/tty is still possible.
This call has been replaced by an automatic mechanism which takes place on process exit.
CX/UX Programmer’s Reference Manual