Safe Pointers* Christoph Grein ESG-Elektroniksystem- und Logistik GmbH, D-81605 MQnchen Christ-Usch.Grein @T-Online.de Access types in A d a have b e e n designed i n a way to p r e v e n t the occurrence o f dangling references, i.e. they cart n e v e r designate objects that have gone out o f scope. T h e r e Unremains however one problem: When checked children providing safe p o i n t e r types for different type glasses is a good idea. package Deallocation is used in order to reclaim storage, we might access already freed storage or, even worse, storage occupied by n e w objects o f different types, unless u t m o s t care is taken (this is the very reason why the generic is called unchecked deallocafion). T h u s in the following fragment (with a suitable i n s t a n u a t i o n for F r e e ) , B.all n o longer exists w h e n it is referenced, b u t n o exception is generally raised: A, A Safe_Pointers pra~m~ Pure; end Safe_Pointers;
/lp/association-for-computing-machinery/safe-pointers-MTDvX8BOcf