Re: _Optional: a type qualifier to indicate pointer nullability

[Christopher Bazley <cs99cjb@gmail.com>]

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On Sat, 4 Feb 2023 at 20:40, Jonathan Wakely <jwakely.gcc@gmail.com> wrote:

>
> On Sat, 4 Feb 2023, 17:01 Christopher Bazley via Gcc, <gcc@gcc.gnu.org>
> wrote:
>
>>
>> Does the lack of support for Clang's nullability qualifiers in GCC
>> indicate
>> a greater likelihood for my proposed feature to be accepted into GCC?
>
>
> No, I don't think so. I think it would be better to support the same
> qualifiers as Clang, not diverge in this way.
>

Clang’s _Nullable qualifier is broken and pretty useless (even according to
the code owner), so good luck with that.

In fact I agree with most of his comment at
>
> https://discourse.llvm.org/t/rfc-optional-a-type-qualifier-to-indicate-pointer-nullability/68004/16
>
> I particularly agree that no new language extension is needed to express a
> pointer that can be null, that's just how pointers have always worked. A
> pointer that cannot be null is more deserving of special attributes or
> qualifiers to say that it has additional guarantees that aren't implied by
> just being a pointer.
>

It’s not a matter what which kind of pointer is “deserving”. One choice is
pleasant and expressive, whereas the other (C with _Nonnull attributes) is
neither type-safe nor ergonomic.

Meanwhile, on Reddit, my proposal has an 85% upvote rate, and on LinkedIn,
“Great idea and I hope it gets itself in to a future standard, but I
couldn't wait for something like that to arrive in C…”

I wonder how many other people “couldn’t wait”. I guess they already left
the debate.

If my proposal has little value to you (quite likely, if you are a C++
>> programmer), please bear in mind that it is just a simple tool (like
>> 'const') that individuals can choose to use, or not. It entails only a
>> minor change to the semantics of one operator. Yes, it is contagious, but
>> nobody will be forced to use _Optional in their project, and it is easy to
>> hide using a macro. I don't feel that it deserves to be killed at birth.
>>
>
> Language extensions don't deserve to be added to a compiler just because
> somebody put a lot of work into them.
>

I never said that they did. You’ve conflated two unrelated paragraphs.

-- 
Christopher Bazley