(PHP 5 >= 5.3.0)
SplQueue::__construct — Constructs a new queue implemented using a doubly linked list
This constructs a new empty queue.
Note:
This method automatically sets the iterator mode to SplDoublyLinkedList::IT_MODE_FIFO.
This function has no parameters.
No value is returned.
Example #1 SplQueue::__construct() example
<?php
$q = new SplQueue();
$q[] = 1;
$q[] = 2;
$q[] = 3;
foreach ($q as $elem)  {
 echo $elem."\n";
}
?>
The above example will output:
1 2 3
Example #2 Efficiently handling tasks with SplQueue
<?php
$q = new SplQueue();
$q->setIteratorMode(SplQueue::IT_MODE_DELETE);
// ... enqueue some tasks on the queue ...
// process them
foreach ($q as $task) {
    // ... process $task ...
    // add new tasks on the queue
    $q[] = $newTask;
    // ...
}
?>