sub getNextPage {
	my ( $tw ) = @_;
	$tw->delete('1.0','end');
	my $start = ( $pointer -1 )  * $pagesize;
	open FH,$messvar or warn "messvar= $messvar $!\n";
	while ( my $line = <FH> ) {	
		next if $. <= $start;
		$tw->insert('end',$line);
		last if $. == ($pointer * $pagesize);
	}
	$tw->see('1.0');
	close FH;
}