Spec#, nullables and more

[Bruno Medeiros]

On 26/11/2010 17:54, Bruno Medeiros wrote:
> On 26/11/2010 17:28, Bruno Medeiros wrote:
>>
>> And I agree with that, and because of that I'm suprised and curious to
>> understand why Hoare mentioned (in the abstract on the link posted
>> originally), that null pointers have caused "innumerable vulnerabilities.
>
> Hum, cool, I just found out that this link:
> http://www.infoq.com/presentations/Null-References-The-Billion-Dollar-Mistake-Tony-Hoare
>
> has the actual presentation on it, so I'm gonna take a look.
>

I've seen the presentation, but he doesn't explain how a null pointer 
access would have caused a vulnerability. I'm going to assume that in 
all likelihood this applied to older computer architectures and/or OSes 
that didn't handle null pointer access that gracefully (1965 is way 
back...). But not so much to modern ones. Or that the vulnerability 
wasn't an actual arbitrary code execution, but some other system failure 
caused by the program crashing.

In any case this side-topic was just a minor curiosity, it's not really 
relevant for D.


But on his talk as a whole, the general point he made was interesting, 
he expressed the desire for languages to have more safety and checking, 
preferably on compile-time, if possible, and if not, on runtime at least 
(rather than have the program corrupt data, or execute crap). He 
mentioned that the big argument against this at that time was 
performance penalties, but that even so a lot of the people/companies 
were happy with the checks that were introduced (like array bounds 
checking), even if initially it didn't seem like a good idea.


-- 
Bruno Medeiros - Software Engineer