Hi,

On 15 November 2023 12:08:49 GMT, Pavel Vazharov via Std-Proposals <std-proposals_at_[hidden]> wrote:
>>
>> Let's say we have a function as follows:
>>
>> void Func(void)
>> {
>> static int one_for_each_callsite = 0;
>> }
>>
>> We want this function to have a unique static-duration variable for
>> each place in the code that this function is called. It would be cool
>> if we could just write the following:
>>
>> template<callsite>
>> void Func(void)
>> {
>> static int one_for_each_callsite = 0;
>> }
>>
>> And so then we could call this function from a few different places:
>>
>> int main(void)
>> {
>> Func(); // This is the 1st call site
>>
>> while ( Something() ) Func(); // This is the 2nd call site
>>
>> Func(); // This is the 3rd call site
>> }
>>
>> So the above code would have three copies of the variable
>> "one_for_each_callsite".
>>
>> If I understood you correctly, you can achieve this today pretty easily
>
>#include <cstdio>
>
>template <typename Tag = decltype([]{})>
>void fun()
>{
> static int counter = 0;
> std::printf("addr:%p value:%i\n", &counter, counter);
>}
>
>int main()
>{
> fun();
> fun();
> fun();
>
> return 0;
>}
>
>This prints something like <https://godbolt.org/z/9Mh8Ea6P8>
>
>addr:0x40401c value:0
>addr:0x404020 value:0
>addr:0x404024 value:0

Isn't this a major ODR-violation footgun?

Cheers,
Lénárd