php howto unset static var

[DylanJD]

i have a function like this. i want reset the $output var first call.\[code\]function create_tree($tree_array, $reset = TRUE, $ul_class = FALSE) { if($reset) unset($output); // NOT WORK!!! static $output = ''; $class = ''; if ($ul_class) { $class = ' class="' . $ul_class . '"'; } $output .= '<ul' . $class . '>' . PHP_EOL; foreach ($tree_array as $v) { $output .= '<li><a href="' . site_url_i18n($v['link']) . '">' . $v['name'] . '</a>' . PHP_EOL;; if (isset($v['children'])) { create_tree($v['children'], false); } $output .= '</li>' . PHP_EOL; } $output .= '</ul>' . PHP_EOL; return $output;}\[/code\]