The Standard PHP Library (SPL) was added to PHP in version 5.0 and is enabled by default. In fact, since PHP 5.3, you cannot disable SPL. Yet, in spite of being part of PHP since 2004, it’s still poorly documented at the time of this writing. There have been calls within the PHP development team for better documentation, so the situation might have improved by the time you read this.
Unable to display preview. Download preview PDF.