Re: A simple question about the "new" allocator

[Adam Beneschan <adambeneschan@gmail.com>]

On Tuesday, August 12, 2014 2:53:36 PM UTC-7, Niklas Holsti wrote:

> It seems to me that if an access type is declared in a block, then
> completion of the block should by these rules cause the collection of
> that access type, being an "object implicitly declared" in the block, to
> cease to exist. For ordinary objects explicitly declared in a block, I
> certainly expect the object's storage to be reclaimed when the object
> ceases to exist on block exit; why should this not apply also to a
> collection object, even if its declaration is implicit?

I see your point.  But unless I've missed something, it's not an RM requirement.

However, if Storage_Size is specified for an access type, I think that the program does have to allocate a pool just for that type, and the storage for the pool does get reclaimed when the block is left.  (13.11(18))  The difference is that when Storage_Size is specified, the expectation is that the program will allocate a contiguous block of memory of that size to be used for allocations for that access type, and that storage block can simply be reclaimed all at once.  If Storage_Size is not specified, there won't be any such contiguous block. 

> I have not found an explicit requirement on reclaiming the storage of a
> collection in the Ada 2012 RM. As I remember, the Ada 83 RM had some
> more explicit text about this, and I remember testing that it worked
> (the collection's storage was reclaimed) with DEC Ada on a VAX.

I can't find anything explicit like this in the Ada 83 RM, even if Storage_Size is specified.

                            -- Adam