SPL
PHP Manual

Predefined Constants

The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.

Warning

SPL uses class constants since PHP 5.1. Prior releases use global constants in the form RIT_LEAVES_ONLY.

RecursiveIteratorIterator::LEAVES_ONLY ( integer )
RecursiveIteratorIterator::SELF_FIRST ( integer )
RecursiveIteratorIterator::CHILD_FIRST ( integer )
CachingIterator::CALL_TOSTRING ( integer )
CachingIterator::CATCH_GET_CHILD ( integer )

SPL
PHP Manual