+ * @param boolean $directories_ok When TRUE, directory names
+ * are acceptable search values,
+ * and when returning a list of
+ * directory contents, sub-directory
+ * names will also be included
+ * (optional; default FALSE).
+ * NOTE that empty directories
+ * are NOT included in the cache!
+ * @param boolean $directories_only When TRUE, only directory names
+ * are included in the returned
+ * results. (optional; default
+ * FALSE). Setting this argument
+ * to TRUE forces $directories_ok
+ * to TRUE as well.
+ * NOTE that empty directories
+ * are NOT included in the cache!