purity question

[Rene Zwanenburg via Digitalmars-d-learn]

On Tuesday, 30 May 2017 at 11:34:52 UTC, ketmar wrote:
>> If malloc were marked as pure, wouldn't that mean it must 
>> return the same pointer every time you call it with the same 
>> size?
>
> of course. but D "pure" is not what other world knows as 
> "pure". we love to mess with words.

Well, there's the ability to modify non-const reference 
parameters from a pure function, but that's not applicable to 
malloc. Are there any other special rules?