sub log
{
  my ($self, $text) = @_;
  if (my $fp = $self->{lfp})
    {
      my $r = $fp->syswrite($text);
      die "$r=log($self->{logfile}): write failed: $text\n" if $r != length($text);
      $self->{lfp_printed}++;
    }
}