Structures as arguments behave like simple variables, not like objects.
When you pass a structure by value, PowerBuilder passes a copy of the structure. You can modify the copy without affecting the original.
When you pass a structure by reference, PowerBuilder passes a reference to the structure. When you changes values in the structure, you are modifying the original. You will not get a null object reference, because structures always exist until they go out of scope.
When you pass a structure as read-only, PowerBuilder passes a copy of the structure. You cannot modify any members of the structure.
