newbie Q: storage management

[kaz@vision.crest.nt.com (Kaz Kylheku)]

I've looked at the ISO standard and the relevant FAQ's and tutorials, but I
still need some discussion or clarification about the management of objects
obtained via ``new'', because what I have read so far seemed rather vague in
one respect.

Whose responsibility is it to destroy these objects? The Ada 95 standard
says that an implementation is permitted to implement garbage collection,
but not required to do so.

I know that it is possible to instantiate a generic freeing function for
explicitly destroying objects. But why is there is this lack of symmetry in the
language?  On the one hand, you have a slick ``new''-expression to create
objects, but the complementary deletion operation is totally obscured. Does
this mean that explicit freeing of objects via an instance of
Unchecked_Deallocation is discouraged (due to the potential creation of
dangling references)? Is it the reponsibility of the language implementation to
automagically detect when an object is no longer reachable and do the
appropriate deallocation, even if garbage is not collected?