Tomas Vondra <tomas.von...@2ndquadrant.com> writes:
> On Tue, Jun 25, 2019 at 11:52:28PM -0400, Tom Lane wrote:
>> You can *not* cast something to an aligned pointer type if it's not
>> actually certain to be aligned suitably for that type.

> OK. So the solution is to ditch the casts altogether, and then do plain
> pointer arithmetics like this:

> #define ITEM_INDEXES(item)                    (item)
> #define ITEM_NULLS(item,ndims)                (ITEM_INDEXES(item) + (ndims))
> #define ITEM_FREQUENCY(item,ndims)    (ITEM_NULLS(item, ndims) + (ndims))
> #define ITEM_BASE_FREQUENCY(item,ndims)       (ITEM_FREQUENCY(item, ndims) + 
> sizeof(double))

> Or is that still relying on alignment, somehow?

No, constructs like a char* pointer plus n times sizeof(something) should
be safe.

                        regards, tom lane


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