Re: GCC 4.0 Ada.Containers Cursor danger.

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

"Dmitriy Anisimkov" <anisimkov@yahoo.com> wrote in message
news:1120615856.997416.158870@g14g2000cwa.googlegroups.com...
...
> <<Note that there is no way in Ada95 to currupt memory other then by
> Unchecked_ or Unrestricted_ access operations. Ada.Containers cursors
> introduce a more "legal" way to do memory curruption.>>

Yes, this argument is incorrect. You can corrupt memory in Ada 95 with
address clauses, Unchecked_Conversion, pragma Suppress, streams,
Sequential_IO, Direct_IO, Storage_IO, and probably some other ways that I've
forgotten.

And, as I've said several times, I think a containers implementation that
corrupts memory as you describe is wrong. Not wrong by the letter of the
Standard, but wrong from the intent of Ada.

If you want to claim that the Standard should say something else, that's
fine, but the truth is that there are a lot of things that the Standard
allows that implementers really should not take advatange of. For instance,
most uses of Unchecked_Conversion allow erroneous execution (and likely
memory corruption) in code far away from the conversion. This is a really
bad thing, and I would hope that most implementations don't take advantage
of it. But the Standard still allows it, because it is thought to be
critical to getting appropriate performance in some cases.

                        Randy Brukardt