std::hash
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< cpp | memory | unique ptr
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| template<class T, class Deleter> struct hash<unique_ptr<T, Deleter>>; |
(начиная с C++11) | |
Шаблон специализации std::hash для std::unique_ptr<T, Deleter> позволяет пользователям получить хэши объектов типа std::unique_ptr<T, Deleter>.
Original:
The template specialization of std::hash for std::unique_ptr<T, Deleter> allows users to obtain hashes of objects of type std::unique_ptr<T, Deleter>.
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Для данного std::unique_ptr<T, Deleter> p, эта специализация гарантирует, что std::hash<std::unique_ptr<T, Deleter>>()(p) == std::hash<T*>()(p.get()).
Original:
For a given std::unique_ptr<T, Deleter> p, this specialization ensures that std::hash<std::unique_ptr<T, Deleter>>()(p) == std::hash<T*>()(p.get()).
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[править] Пример
#include <iostream> #include <memory> #include <functional> struct Foo { Foo() { std::cout << "Foo...\n"; } ~Foo() { std::cout << "~Foo...\n\n"; } }; int main() { Foo* foo = new Foo(); std::unique_ptr<Foo> up(foo); std::cout << "hash(up): " << std::hash<std::unique_ptr<Foo>>()(up) << '\n'; std::cout << "hash(foo): " << std::hash<Foo*>()(foo) << '\n'; }
Вывод:
Foo... hash(up): 3686401041 hash(foo): 3686401041 ~Foo...
[править] См. также
| (C++11) |
hash function object (шаблон класса) |
