SPL is a collection of interfaces and classes that are meant to solve standard problems.
Tip: A more detailed documentation of SPL can be found here.
This extension is available and compiled by default in PHP 5.
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.
SPL uses class constants since PHP 5.1. Prior releases use global constants in the form RIT_LEAVES_ONLY.