# $config is given

sub get_file_watcher_ref {
    my %setting_for;
    my (
        $watch_interval,
        $watch_file_min_size,
        $term_run_time,
    );
    
    if ( $watch_interval = $config->{watch_interval} ) {
        $setting_for{watch_interval} = $watch_interval;
    }
    if ( $watch_file_min_size = $config->{watch_file_min_size} ) {
        $setting_for{watch_file_min_size} = $watch_file_min_size;
    }
    if ( $term_run_time = $config->{term_run_time} ) {
        $setting_for{term_run_time} = $term_run_time;
    }

    return \%setting_for;
}