snoop() - snoop an interactive user
varargs object snoop( object snooper, object snoopee );
When both arguments are used, begins snooping of 'snoopee' by
'snooper'. If the second argument is omitted, turns off all snooping
by 'snoopee'. Security for snoop() is normally controlled by a
simul_efun. snoop() returns 'snoopee' if successful in the two-argu‐
ment case, and 'snooper' if it was successful in the single-argument
case. A return of 0 indicates failure.
query_snoop(3), query_snooping(3)