Re: Creation of storage pools

[Tucker Taft <stt@averstar.com>]

Matthew Heaney wrote:
> 
> Graeme Perkes <graeme.perkes@sydney.gecm.com> writes:
> 
> > The problem is how to use the storage pools I've created.
> > I'm having trouble with  "for XYZ'storage_pool use ..." syntax
> > when used with a USER_POOL access variable:
> >
> >    STORAGE_POOLS_LIST : POOL_CFG_PTR := null;
> >
> >    -- STORAGE_POOLS_LIST is populated by an initialisation procedure
> >
> >    MY_POOL : POOL_LIST.POOL_PTR := STORAGE_POOLS_LIST(I);
> >
> >    type INT_ACC is access INTEGER;
> >    for INT_ACC'storage_pool use MY_POOL.all;
> >
> > GNAT 3.11b2 responds with the following error for the use clause:
> >
> >       "incorrect reference to a Storage Pool"
> >
> > What am I doing wrong?
> 
> Aren't attribute rep clauses static?  

Not all of them.  Clearly those that require that the
expression denote a variable can't require that it be a static
expression.

> ... You have to bind to a statically
> declared storage pool object, not a dynamically declared one.

Not necessarily true in this case, though conceivably
GNAT may have such a restriction.  The only hard requirement 
is that the storage pool object denoted be a variable (see RM95 13.11(15)).

> ...
> > Am I trying to violate basic principles of storage pools?
> 
> It would appear so.

No, you are not violating any basic principle.  Conceivably
GNAT has a restriction (or bug) in this area.

> See the package System.Pool_Global, in the gnat sources, for an example.

-- 
-Tucker Taft   stt@averstar.com   http://www.averstar.com/~stt/
Technical Director, Distributed IT Solutions  (www.averstar.com/tools)
AverStar (formerly Intermetrics, Inc.)   Burlington, MA  USA