sunos man page for vhangup

vhangup(2)							   System Calls 							vhangup(2)

NAME
       vhangup - virtually "hangup" the current controlling terminal

SYNOPSIS
       #include <unistd.h>

       void vhangup(void);

DESCRIPTION
       The  vhangup()  function  is used by the initialization process init(1M) (among others) to ensure 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  refer-
       ences  to  the  controlling terminal of the invoking process and revokes 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 or EIO). A SIGHUP (hangup signal) is sent to
       the process group of the controlling terminal.

SEE ALSO
       init(1M)

BUGS
       Access to the controlling terminal using /dev/tty is still possible.

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

SunOS 5.10							    19 Mar 1998 							vhangup(2)