Re: pointer questions

[Simon Wright <simon@pushface.org>]

David <kdgreen@fastmail.fm.au> writes:

> I develop larg'ish mission-critical systems in Ada and cannot use
> pointers, dynamic memory allocation, tasks, variants, recursion,
> etc. etc.  You can always find a way to not use pointers as long as
> you stick to Ada (not interfacing C/C++).   Memory mapped hardware can
> be accessed using an expression like "for x'address use at <hardware
> address>".  You can declare one variable on top of another the same
> way.
>
> Trying to get code safety-certified with pointers is very difficult
> to impossible.  Code that doesn't use pointers is invariably simpler
> and more reliable but it may require more thought depending upon
> mind-set.

Do the rules allow unchecked conversion?

Using "for x'address use" to "declare one variable on top of another"
is a way of trying to pretend to the auditor that you aren't doing
unchecked conversion ... much safer to do UC, at least the compiler
has a chance to tell you that (for instance) the things concerned
aren't the same size!