In order to support garbage collecting and non-garbage collecting memory managers gmm provides three modes 1. NoGC allocates an uncollectable item. AtGC allocates a collectable atomic item, i.e. an object containing no pointers in it. GC allocates a collectable item. A note on the philosophy of this approach.
Garbage collection is expensive in execution resources.
It is clear that avoiding the use of automatic collection implies more work. The memory is set to zero. The memory ist not cleared. The memory ist not cleared and will not be collected by the implemented memory manager. The memory ist not cleared.