SPL is a collection of interfaces and classes that are meant to solve standard problems.
A more detailed documentation of SPL can be found » here.
This extension is available and compiled by default in PHP 5.
Konštanty uvedené nižšie sú definované týmto rozšírením a budú dostupné iba keď rozšírenie bolo buď kompilované do PHP alebo dynamicky načítané za behu (runtime).
SPL uses class constants since PHP 5.1. Prior releases use global constants in the form RIT_LEAVES_ONLY.