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) (among
     others) 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 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 hangup signal (SIGHUP) is sent
     to the process group of the control terminal.

SEE ALSO
     init (8)

BUGS
     Access to the control terminal via /dev/tty is still possi-
     ble.

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




























Printed 11/26/99	  June 30, 1985                         1