subr view_set_time(win)
 sq = '$viewclockboxtext'+ string(win)
 t =$view_tai(win)
 if t le 0.0 then s = 'time not\nknown' else {
   s = strtok(date_from_tai(t,0,1),'U') }
 xmsetlabel, eval(sq), s
 xtmanage, eval('$viewclockbox'+ string(win))
 endsubr
 ;============================================================