VHANGUP(2)          UNIX Programmer's Manual           VHANGUP(2)

NAME
     vhangup - virtually ``hangup'' the current control terminal

SYNOPSIS
     vhangup()

DESCRIPTION
     _V_h_a_n_g_u_p is used by the initialization process _i_n_i_t(8) to
     arrange that users are given ``clean'' terminals at login,
     by revoking access of the previous users' processes to the
     terminal.  To effect this, _v_h_a_n_g_u_p searches the system
     tables for references to the control terminal of the invok-
     ing 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.

ERRORS
     _V_h_a_n_g_u_p will fail if:

     [EPERM]             The process's effective user ID is not
                         the super-user.

SEE ALSO
     init(8)

BUGS
     Access to the control terminal via /_d_e_v/_t_t_y is still possi-
     ble.

     This call is peculiar to this version of UNIX.  The options
     and specifications of this system call and even the call
     itself are subject to change.

Printed 5/22/83                                                 1