19 General utilities library [utilities]

19.11 Smart pointers [smartptr]

19.11.3 Class template shared_­ptr [util.smartptr.shared]

19.11.3.7 Comparison [util.smartptr.shared.cmp]

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template<class T, class U> bool operator==(const shared_ptr<T>& a, const shared_ptr<U>& b) noexcept;
1
#
Returns: a.get() == b.get().
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template<class T, class U> bool operator<(const shared_ptr<T>& a, const shared_ptr<U>& b) noexcept;
2
#
Returns: less<>()(a.get(), b.get()).
3
#
[ Note
:
Defining a comparison function allows shared_­ptr objects to be used as keys in associative containers.
— end note
 ]
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template<class T> bool operator==(const shared_ptr<T>& a, nullptr_t) noexcept; template<class T> bool operator==(nullptr_t, const shared_ptr<T>& a) noexcept;
4
#
Returns: !a.
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template<class T> bool operator!=(const shared_ptr<T>& a, nullptr_t) noexcept; template<class T> bool operator!=(nullptr_t, const shared_ptr<T>& a) noexcept;
5
#
Returns: (bool)a.
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template<class T> bool operator<(const shared_ptr<T>& a, nullptr_t) noexcept; template<class T> bool operator<(nullptr_t, const shared_ptr<T>& a) noexcept;
6
#
Returns: The first function template returns 
less<typename shared_ptr<T>::element_type*>()(a.get(), nullptr)
The second function template returns 
less<typename shared_ptr<T>::element_type*>()(nullptr, a.get())
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template<class T> bool operator>(const shared_ptr<T>& a, nullptr_t) noexcept; template<class T> bool operator>(nullptr_t, const shared_ptr<T>& a) noexcept;
7
#
Returns: The first function template returns nullptr < a.
The second function template returns a < nullptr.
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template<class T> bool operator<=(const shared_ptr<T>& a, nullptr_t) noexcept; template<class T> bool operator<=(nullptr_t, const shared_ptr<T>& a) noexcept;
8
#
Returns: The first function template returns !(nullptr < a).
The second function template returns !(a < nullptr).
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template<class T> bool operator>=(const shared_ptr<T>& a, nullptr_t) noexcept; template<class T> bool operator>=(nullptr_t, const shared_ptr<T>& a) noexcept;
9
#
Returns: The first function template returns !(a < nullptr).
The second function template returns !(nullptr < a).