RecursiveIteratorIterator::getSubIterator The current active sub iterator &reftitle.description; public RecursiveIteratornullRecursiveIteratorIterator::getSubIterator intnulllevel&null; &warn.undocumented.func; &reftitle.parameters; level &reftitle.returnvalues; The current active sub iterator on success; &null; on failure. &reftitle.changelog; &Version; &Description; 8.0.0 level is now nullable.