Issue 3374: P0653 + P1006 should have made the other std::to_address overload constexpr

Title: P0653 + P1006 should have made the other std::to_address overload constexpr
Status: c++20
Section: [pointer.conversion]
Submitter: Billy O'Neal III

Created on 2020-01-14.00:00:00 last changed 45 months ago

Messages

Date: 2020-02-01.13:19:22

Proposed resolution:

This wording is relative to N4842.

Modify [memory.syn], header <memory> synopsis, as indicated:

[…]
// [pointer.conversion], pointer conversion
template<class T>
  constexpr T* to_address(T* p) noexcept;
template<class Ptr>
  constexpr auto to_address(const Ptr& p) noexcept;
[…]

Modify [pointer.conversion] as indicated:
```
template<class Ptr> constexpr auto to_address(const Ptr& p) noexcept;
```
-3- Returns: pointer_traits<Ptr>::to_address(p) if that expression is well-formed (see [pointer.traits.optmem]), otherwise to_address(p.operator->()).

msg10949 (view)

Date: 2020-02-01.00:00:00

[ 2020-02-01 Status set to Tentatively Ready after seven positive votes on the reflector. ]

msg10948 (view)

Date: 2020-01-14.00:00:00

While reviewing some interactions with P0653 + P1006, Billy discovered that one of the overloads was missing the constexpr tag. This might be a typo or a missed merge interaction between P0653 (which adds to_address with the pointer overload being constexpr) and P1006 (which makes pointer_traits::pointer_to constexpr). Mail was sent the LWG reflector, and Glen Fernandes, the author of P0653, indicates that this might have been an oversight.

History
Date	User	Action	Args
2021-02-25 10:48:01	admin	set	status: wp -> c++20
2020-02-24 16:02:59	admin	set	status: immediate -> wp
2020-02-14 06:37:09	admin	set	status: ready -> immediate
2020-02-01 13:19:22	admin	set	messages: + msg10974
2020-02-01 13:19:22	admin	set	status: new -> ready
2020-01-18 17:49:42	admin	set	messages: + msg10949
2020-01-14 00:00:00	admin	create