On Wed, 11 Mar 2020 at 23:01, David Stone via SG15 <sg15_at_[hidden]>
wrote:

> On Mon, Mar 9, 2020 at 5:14 AM Bryce Adelstein Lelbach aka wash via
> Modules <modules_at_[hidden]> wrote:
>
>> As I recall, we did not have consensus to evolve the ABI at Prague.
>>
>
> As a reminder, these were the polls:
>
> 1. We should consider a big ABI break for C++23
> SF F N A SA
> 17 44 15 31 20
>
> Not consensus
>
> 2. We should consider a big ABI break for C++SOMETHING
> SF F N A SA
> 39 41 14 23 14
>
> That looks consensus-y
>
> 3. From now on, we should consider incremental ABI for every C++ release
> SF F N A SA
> 98 35 6 0 2
>
> Consensus
>
> 4. When we are unable to resolve a conflict between performance and ABI
> compatibility, we should prioritize performance
> SF F N A SA
> 41 26 39 13 13
>
> Consensus
>
> 5. To the best of our ability, we should promise users that we won’t break
> ABI, ever.
> SF F N A SA
> 3 3 12 43 70
>
> No consensus
>
>
> My understanding of these results is that there is no plan to
> intentionally break everything that could potentially benefit from it in
> C++23, but we did not vote to reject any proposal targeted at C++23 that
> would break ABI. I think this is an important but subtle difference. There
> is a strong argument in favor of the "big ABI break" approach, which is to
> make it more obvious to users that they cannot mix modes, but the results
> of the first and second polls together say that we want to do that at some
> point, but 3 years is insufficient time for anything that large.
>
> Importantly, we never took a vote saying we do not want to break ABI at
> all in C++23, and we specifically took a vote that found we do plan on
> breaking ABI as a general concept.
>

For impacted users, all abi breaks are abi breaks, there are no big or or
small, the only difference is that we know how to make big breaks link-time
diagnosable.
To come back on topic, giving ownership of standard entities to modules
would be a "big" break and wg21 voted against "big"



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