What are the advantages of using SplFixedArray instead of an array?

What are the advantages of using SplFixedArray instead of an array?

What are the advantages of setting a value for an array (in PHP)?

Example with array :

$arr = array();

$arr[0] = 'Stack';

$arr[1] = 'Overflow';

$arr[2] = 'blablabla';

Example with SplFixedArray

$arr = new SplFixedArray(2);

$arr[0] = 'Stack';

$arr[1] = 'Overflow';

$arr[2] = 'blablabla'; // RunTimeException: Index invalid or out of range