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Subject: Re: C++ 20: Member templates. Is there a typo in the following example?
From: Will Hawkins (hawkinsw_at_[hidden])
Date: 2019-08-24 04:46:36


On Fri, Aug 23, 2019 at 11:55 PM Tom Honermann via Std-Discussion
<std-discussion_at_[hidden]> wrote:
>
> On 8/21/19 11:41 AM, Vladimir Grigoriev via Std-Discussion wrote:
>
> In the p.#2 of the section "13.6.2 Member templates" there is the following example
>
> template <class T>struct A {
> void f(int);
> template <class T2> void f(T2);
> };
>
> template <> void A<int>::f(int) { } // non-template member function
> template <> template <> void A<int>::f<>(int) { } // member function template specialization
>
> int main() {
> A<char> ac;
> ac.f(1); // non-template
> ac.f(’c’); // template
> ac.f<>(1); // template
> }
>
> However there is no definition for example for the specialization of the non-template function for A<char>. So the code is invalid. That is the compiler will issue an error.
>
> A definition is not required for compilation to succeed. A definition is required (somewhere) for the final program to link successfully.
>
>
> Should the template specializations be done in this example for A<char> instead of A<int>?
>
> No. The point of the example is to demonstrate the syntax needed to declare and call specific specializations of those two class template members. The fact that definitions of the two members cannot be (implicitly) instantiated for the A<char> specialization within that translation unit is immaterial.

I apologize that my reply was inaccurate. I completely missed the fact
that there is no actual definition for the template member function f.

Will

>
> Tom.
>
>
> With best regards,
> Vlad from Moscow
>
> You can meet me at http://cpp.forum24.ru/ or www.stackoverflow.com or http://ru.stackoverflow.com
>
>
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