proc trf_block y {
# $Header: /home/cvsroot/tcldb/ucodb/Tlib/trf_block,v 1.1.1.1 1996/10/12 01:08:27 de Exp $
	global trf_wid trf_len trf_sav trf_pag trf_lin
	global trf_arr trf_blk trf_fp trf_pnf trf_pnx trf_pny trf_pnn

#	y is 0 for turn off block, . or line num for turn on block

	if {$y == "."} {
		set y $trf_lin
	} else {
		if {$y > $trf_len} {
			puts stderr "WARNING, cannot start block at line $y, would force a new page"
			return
		}
	}

	set trf_blk $y

}
