std.allocator.allocate(0) -> return null or std.allocator.allocate(1)?

[Timon Gehr via Digitalmars-d]

On 05/15/2015 09:49 PM, Andrei Alexandrescu wrote:
> On 5/15/15 11:51 AM, Andrei Alexandrescu wrote:
>> On 5/15/15 11:37 AM, deadalnix wrote:
>>> On Friday, 15 May 2015 at 16:36:29 UTC, Andrei Alexandrescu wrote:
>>>> This is a matter with some history behind it. In C, malloc(0) always
>>>> returns a new, legit pointer that can be subsequently reallocated,
>>>> freed etc. What most malloc() implementations practically do in their
>>>> first line is:
>>>>
>>>> if (size == 0) size = 1;
>>>>
>>>> and take it from there.
>>>>
>>>
>>> There are actually 2 way to do this in malloc. Either you return null,
>>> but then you need to be able to accept null in the free implementation
>>> (as malloc must return a freeable pointer) or you just bump to 1.
>>>
>>> Both are valid per spec and there are implementations of malloc for
>>> both.
>>
>> Ah, nice. I was under the misconception that malloc(0) cannot return
>> null in C. Apparently it's implementation defined at least since C99,
>> see http://stackoverflow.com/a/2132318/348571. Thanks!
>
> Well I added the rule that allocate(0) should return null, there are a
> few more tests but probably nothing worrisome:
> https://github.com/andralex/phobos/commit/f73f6ecf1b45b0fc3cffd50d375eb15eb2311220
>
>
> Andrei
>
>

- Quantizer currently does not necessarily follow this rule.

- Might it not be surprising behaviour for AffixAllocator?