This page is a snapshot from the LWG issues list, see the Library Active Issues List for more information and the meaning of C++23 status.

3771. [fund.ts.v3] remove binders typedefs from function

Section: 99 [fund.ts.v3::func.wrap.func.overview] Status: C++23 Submitter: Alisdair Meredith Opened: 2022-09-12 Last modified: 2023-11-22

Priority: Not Prioritized

View all issues with C++23 status.

Discussion:

Addresses: fund.ts.v3

The LFTSv3 bases its specification for experimental::function on std::function in the C++20 standard. However, the wording was largely copied over from LFTSv2 which based its wording on the C++14 standard.

For C++17, we removed the conditionally defined typedefs for the legacy binders API, but this removal was not reflected in the TS. We are now left with a specification referring to unknown types, T1 and T2.

These typedefs should be excised to match the referenced standard.

[2022-09-23; Reflector poll]

Set status to Tentatively Ready after ten votes in favour during reflector poll.

[2022-11-12 Approved at November 2022 meeting in Kona. Status changed: Voting → WP.]

Proposed resolution:

This wording is relative to N4920.

1. Modify the synopsis in 99 [fund.ts.v3::func.wrap.func.overview] as indicated:

   namespace std {
     namespace experimental::inline fundamentals_v3 {
   
       template<class> class function; // undefined
   
       template<class R, class... ArgTypes>
       class function<R(ArgTypes...)> {
       public:
         using result_type = R;
         using argument_type = T1;
         using first_argument_type T1;
         using second_argument_type = T2;
   
         using allocator_type = erased_type;
   
         // ...
     }
   }