Example 1. spl_classes() example
<?php
print_r(spl_classes());
?>  | 
The above example will output 
something similar to:
Array
(
    [ArrayObject] => ArrayObject
    [ArrayIterator] => ArrayIterator
    [CachingIterator] => CachingIterator
    [CachingRecursiveIterator] => CachingRecursiveIterator
    [DirectoryIterator] => DirectoryIterator
    [FilterIterator] => FilterIterator
    [LimitIterator] => LimitIterator
    [ParentIterator] => ParentIterator
    [RecursiveDirectoryIterator] => RecursiveDirectoryIterator
    [RecursiveIterator] => RecursiveIterator
    [RecursiveIteratorIterator] => RecursiveIteratorIterator
    [SeekableIterator] => SeekableIterator
    [SimpleXMLIterator] => SimpleXMLIterator
) |