Re: Gem 39 - compiler specific?

["Randy Brukardt" <randy@rrsoftware.com>]

"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message 
news:19268dbw82hf4.aii8as09aapk.dlg@40tude.net...
> On Wed, 2 Sep 2009 18:20:36 -0500, Randy Brukardt wrote:
...
>> (As an aside, this technique could not work in Janus/Ada if Buffer was an
>> unconstrained array: 'Address of an unconstrained array points at the 
>> array
>> descriptor, not the data.
>
> It must point to the first array element 13.3(14). BTW, it is interesting
> where it should point when the array is empty.

The word in 13.3(14) is "should", not "must" (a word that is not allowed in 
Standards anyway). Specifically,
13.3(14) is Implementation Advice. There is no requirement in Ada to follow 
Implementation Advice, the only requirement is to document when you don't. 
That is, an Ada compiler's (formal) correctness cannot depend on 
Implementation Advice. What Janus/Ada does here is OK (but not recommended 
of course).

                      Randy.