Mat gave me this idea from my >Stack UDF thread. It works like a stack, but instead of being LIFO (last in first out), it's FIFO (first in first out).   Enjoy. Global Const $QUEUE_GUID = 'BB09E988-0DF3-11E4-846E-B46DECBA0006' Global Enum $QUEUE_COUNT, $QUEUE_FIRSTINDEX, $QUEUE_LASTINDEX, $QUEUE_ID, $QUEUE_UBOUND, $QUEUE_MAX #Region Example #include <Array.au3> Example() Func Example() Local $hQueue = Queue() ; Create a queue object. For $i = 1 To 20 If Queue_Enqueue($hQueue, 'E