On 06/03/2026 22:10, Jens Maurer wrote:
>
>
> On 3/6/26 22:50, Lénárd Szolnoki wrote:
>>
>>
>> On 06/03/2026 17:32, Jens Maurer via Std-Discussion wrote:
>>>
>>> Annotations on block-scope function declarations will be disallowed by CWG3124:
>>>
>>> https://cplusplus.github.io/CWG/issues/3124.html
>>>
>>> Jens
>>
>> Are extern "C" function declarations in different namespaces in a similar place regarding
>> this?
>
> I don't think so.
>
>> There is implementation divergence there:
>
> Please file a bug report with the respective vendor.
> This is a fairly new feature, so some shady corner-
> cases are expected to surface.

Thanks for the input, I filed https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124394 .

Lénárd

>
> Jens
>
>
>>
>> #include <meta>
>>
>> extern "C" {
>> [[=1]] void function();
>>
>> static_assert(annotations_of(^^function).size() == 1);
>>
>> namespace N {
>> [[=2]] void function();
>> }
>> }
>>
>> int main() {
>> static constexpr auto NumAnnotations = annotations_of(^^function).size();
>>
>> // GCC: 1, clang: 2
>> std::printf("Annotation count: %zu", NumAnnotations);
>> }
>>
>> https://godbolt.org/z/4qeza4fPv
>>
>>>
>>> On 3/6/26 03:06, Keenan Horrigan via Std-Discussion wrote:
>>>> Hello,
>>>>
>>>> I was wondering what the proper behavior of the following code should be:
>>>>
>>>> #include <meta>
>>>>
>>>> [[=1]]
>>>> void function();
>>>>
>>>> static_assert(annotations_of(^^function).size() == 1);
>>>>
>>>> template<auto Value>
>>>> consteval void annotate_function() {
>>>> [[=Value]]
>>>> void function();
>>>> }
>>>>
>>>> consteval {
>>>> annotate_function<2>();
>>>> }
>>>>
>>>> int main() {
>>>> static constexpr auto NumAnnotations = annotations_of(^^function).size();
>>>>
>>>> std::printf("Annotation count: %zu", NumAnnotations);
>>>> }
>>>>
>>>> Godbolt link: https://godbolt.org/z/4dca5xEPe
>>>>
>>>> With GCC trunk, it prints "Annotation count: 1", but with the experimental Clang reflection branch it prints "Annotation count: 3". I assume Clang here is acting erroneously in some regard because it appears to be duplicating the initial annotation placed on the function. But what I'm more interested in is whether the compiler should be appending the annotation from annotate_function globally.
>>>>
>>>> As well, if one removes the templating from annotate_function, GCC continues to report only one annotation, but Clang reports two: https://godbolt.org/z/74evKWT3a
>>>>
>>>> I'd also be interested in how that is meant to behave.
>>>>
>>>> Thanks
>>>
>>> --
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>>
>