Re: C array to Ada pointer to unconstrained array without copying memory

[Duncan Sands <duncan.sands@math.u-psud.fr>]

Hi Steve, thanks for the interesting information.

> For infomration the Fat pointer is a struct with two pointers, one to the
> bounds and one to the data. Surprise is that the layout of the bounds and
> data in memory is the same, so they are allocated in a single call, this
> means thin and fat are the same at the basest level, you just have more
> overhead for fats.

Do you mean that the bounds are also stored directly before the data in
memory?  If so, it should still be possible to have the two pointers point
to quite different memory areas - after all, when you use an address clause
to say that the data is somewhere, the bounds will be on the stack and thus
not immediately before the data.  Does this mean that if you free a fat
pointer using Unchecked_Deallocation, then only the memory pointed to by
the bounds part is freed?  (Because the memory is allocated as one block,
the bounds point to the start, the data a bit further along).

Thanks again for your help - I'm glad someone understood my question.

All the best,

Duncan.