From Jason Turner

[util.smartptr.ownerless]

C++23 → Trunk 2.8 KB 30 lines
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  1. tmp/tmpj8_69v_g/{from.md → to.md} +12 -14
tmp/tmpj8_69v_g/{from.md → to.md} RENAMED
@@ -6,30 +6,30 @@ of shared and weak pointers.
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  ``` cpp
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  namespace std {
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  template<class T = void> struct owner_less;
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  template<class T> struct owner_less<shared_ptr<T>> {
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- bool operator()(const shared_ptr<T>&, const shared_ptr<T>&) const noexcept;
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- bool operator()(const shared_ptr<T>&, const weak_ptr<T>&) const noexcept;
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- bool operator()(const weak_ptr<T>&, const shared_ptr<T>&) const noexcept;
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  };
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  template<class T> struct owner_less<weak_ptr<T>> {
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- bool operator()(const weak_ptr<T>&, const weak_ptr<T>&) const noexcept;
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- bool operator()(const shared_ptr<T>&, const weak_ptr<T>&) const noexcept;
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- bool operator()(const weak_ptr<T>&, const shared_ptr<T>&) const noexcept;
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  };
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  template<> struct owner_less<void> {
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  template<class T, class U>
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- bool operator()(const shared_ptr<T>&, const shared_ptr<U>&) const noexcept;
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  template<class T, class U>
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- bool operator()(const shared_ptr<T>&, const weak_ptr<U>&) const noexcept;
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  template<class T, class U>
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- bool operator()(const weak_ptr<T>&, const shared_ptr<U>&) const noexcept;
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  template<class T, class U>
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- bool operator()(const weak_ptr<T>&, const weak_ptr<U>&) const noexcept;
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  using is_transparent = unspecified;
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  };
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  }
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  ```
@@ -40,12 +40,10 @@ namespace std {
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  Note that
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  - `operator()` defines a strict weak ordering as defined in 
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  [[alg.sorting]];
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- - two `shared_ptr` or `weak_ptr` instances are equivalent under the
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- equivalence relation defined by `operator()`,
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- `!operator()(a, b) && !operator()(b, a)`, if and only if they share
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- ownership or are both empty.
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  — *end note*]
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  ``` cpp
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  namespace std {
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  template<class T = void> struct owner_less;
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  template<class T> struct owner_less<shared_ptr<T>> {
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+ constexpr bool operator()(const shared_ptr<T>&, const shared_ptr<T>&) const noexcept;
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+ constexpr bool operator()(const shared_ptr<T>&, const weak_ptr<T>&) const noexcept;
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+ constexpr bool operator()(const weak_ptr<T>&, const shared_ptr<T>&) const noexcept;
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  };
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  template<class T> struct owner_less<weak_ptr<T>> {
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+ constexpr bool operator()(const weak_ptr<T>&, const weak_ptr<T>&) const noexcept;
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+ constexpr bool operator()(const shared_ptr<T>&, const weak_ptr<T>&) const noexcept;
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+ constexpr bool operator()(const weak_ptr<T>&, const shared_ptr<T>&) const noexcept;
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  };
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  template<> struct owner_less<void> {
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  template<class T, class U>
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+ constexpr bool operator()(const shared_ptr<T>&, const shared_ptr<U>&) const noexcept;
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  template<class T, class U>
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+ constexpr bool operator()(const shared_ptr<T>&, const weak_ptr<U>&) const noexcept;
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  template<class T, class U>
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+ constexpr bool operator()(const weak_ptr<T>&, const shared_ptr<U>&) const noexcept;
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  template<class T, class U>
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+ constexpr bool operator()(const weak_ptr<T>&, const weak_ptr<U>&) const noexcept;
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  using is_transparent = unspecified;
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  };
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  }
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  ```
 
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  Note that
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  - `operator()` defines a strict weak ordering as defined in 
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  [[alg.sorting]];
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+ - `!operator()(a, b) && !operator()(b, a)` is `true` if and only if
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+ `a.owner_equal(b)` is `true`.
 
 
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  — *end note*]
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