Linux man pages : vhangup (2)
VHANGUP(2) Linux Programmer's Manual VHANGUP(2)
vhangup - virtually hangup the current tty
vhangup simulates a hangup on the current terminal. This call arranges
for other users to have a "clean" tty at login time.
On success, zero is returned. On error, -1 is returned, and errno is
EPERM The user is not the super-user.
This call is Linux-specific, and should not be used in programs
intended to be portable.
Linux 0.99.11 1993-07-24 VHANGUP(2)