Re: Storage allocation for aligned structures

["Paul Jackson" <paulgjackson@xxxxxxxxx>]

On Fri, Jun 6, 2008 at 4:02 PM, Jon Paris <Jon.Paris@xxxxxxxxxxxxxx> wrote:
> On 6-Jun-08, at 5:40 PM, rpg400-l-request@xxxxxxxxxxxx wrote:
>
> > I am concerned that if I use the %size value when allocating storage
> > that I am not giving sufficient space to the structure which could
> > cause issues with corrupted memory.   Should I be allocating 656 to
> > each element of myds or 644?
> >
> > Thanks for any comments on this question.
> >
> > -Paul
> >
> >      D myds            ds                  likeds(regex_t)
> >      D                                     dim(64)
> >      D                                     based(pMyds)
>
> Given that you are not really using that much storage, I'm not sure
> why you are bothering with dynamic memory.  That said - you _must_
> allocate in multiples of 656.  That is how big each element is
> because there is a pad of 12 bytes required at the end of each
> element in order to align the following element.
>
> You should still be able to use %Size to calculate your requirements
> like so: actualSize = ( %Size(arrayname: *all) / %Elem(arrayname) )

Thanks Scott, Barbara and Jon for your explanations/responses and the
named constant tip!

-Paul