Re: Problems with Scope of aliased Objects

["patrick.gunia@googlemail.com" <patrick.gunia@googlemail.com>]

On 16 Apr., 18:26, Adam Beneschan <a...@irvine.com> wrote:
> On Apr 16, 8:59 am, "patrick.gu...@googlemail.com"
>
> > Alright, this was my explanation. I forgot the fact, that the values
> > are copied into the array. The simple reason why I didn´t want to use
> > heap-memory is the performance-aspect. My third approach works using
> > "new" to allocate heap-memory dynamically. In this case, adding the
> > access-type into the array leads to a copy of the heap-memory-adress
> > where the object was created. This address is copied into the array
> > and thus still reachable. To cut a long story short, my second
> > approach simply won´t work because of dangling pointers which point to
> > memory which isn´t assigned any longer (at least not to the objects I
> > expect to be there). Do I have to be afraid of runtime-performance-
> > problems when using dynamic allocation in Ada?
>
> I don't know.  That will depend on which implementation of Ada you use
> and just what your performance requirements are.  If it's really a
> concern, you can set up your own storage pool, with your own
> allocation and deallocation routines, and tell the compiler that any
> time you use "new" for certain access types, they will use that pool.
> Then you can optimize the pool routines and tailor them to the
> specific way you will use it (for example, if you never deallocate
> anything, you can take advantage of that fact to simply the Allocate
> routine; or you can organize the pool so that all objects of the same
> size will be next to each other, which could lead to a more efficient
> implementation).  Storage pools are explained in 13.11 of the RM, and
> there may be other helpful resources, and I'm sure there are publicly
> available examples of storage pools that you can use or modify---but I
> don't know where they are, so hopefully someone else can point you to
> them.
>
>                               -- Adam

Alright, then I think I´ll search some ressources concerning storage
pools. I use GNAT 3.4.5 (mingw-vista special r3) with Ada95. Indeed I
deal with a situation in which the dynamic-allocation is performed
while initializing the software and freed when shutting it down. Thus
I usually don´t have to deallocate the dynamically allocated memory as
the runtime-system frees it at program-shutdown. This might be a
starting-point for optimization.
Thank you!