sub irregular_run_mode {
  my $app = shift;
  $app->header_type("none");
  $| = 1;

  print $app->query()->header();


  # code here

  return "";
}

##</code><code>##

sub cgiapp_postrun {
  my ($app,$outref) = @_;
  return $outref if $app->get_current_runmode() eq "irregular_run_mode";

  # ...
}