cppdraft_translate/cppdraft/util/smartptr/shared/cmp.md

[util.smartptr.shared.cmp]

20 Memory management library [mem]

20.3 Smart pointers [smartptr]

20.3.2 Shared-ownership pointers [util.sharedptr]

20.3.2.2 Class template shared_ptr [util.smartptr.shared]

20.3.2.2.8 Comparison [util.smartptr.shared.cmp]

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template<class T, class U> constexpr bool operator==(const shared_ptr<T>& a, const shared_ptr<U>& b) noexcept;

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Returns: a.get() == b.get().

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template<class T> constexpr bool operator==(const shared_ptr<T>& a, nullptr_t) noexcept;

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Returns: !a.

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template<class T, class U> constexpr strong_ordering operator<=>(const shared_ptr<T>& a, const shared_ptr<U>& b) noexcept;

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Returns: compare_three_way()(a.get(), b.get()).

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[Note 1:

Defining a comparison operator function allows shared_ptr objects to be used as keys in associative containers.

— end note]

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template<class T> constexpr strong_ordering operator<=>(const shared_ptr<T>& a, nullptr_t) noexcept;

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Returns: compare_three_way()(a.get(), static_cast<typename shared_ptr::element_type*>(nullptr))