Re: GNAT "alignment value must be positive"

[marciant@earthlink.net]

On Wednesday, April 8, 2015 at 4:35:23 PM UTC-4, Randy Brukardt wrote:
> ...
>
> I should have added that the Recommended Level of Support does seem to 
> require supporting that (probably should have read it before pushing 
> "send"!), so in that sense, it's a GNAT bug to not allow it. But 
> practically, 0 and 1 are the same for a specified alignment; nothing is 
> going to be different about the default allocation, so it's doesn't really 
> matter.
> 
>                                             Randy.

Are you saying that it is not necessary to specify alignment zero for records that end up specifying components of enclosing records whose layout is being fully "rep-spec'd" (pragma Pack is not being used?).
Is it not (no longer?) necessary to ever indicate - as per Ada 95 RM 13.3 [14] - "zero means that the object is not necessarily aligned on a storage element boundary."?  Should "object" in the above really be "subtype" or object?  Is it no necessary to indicate "not necessarily aligned on a storage element boundary" for anything?

I know that those are a lot of questions but I am trying to understand enough to gain "full command" of this aspect of the language: I have always (at this point about 25 years!) been very interested in hardware and communication interface design in Ada.