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>>; |
（C++11 起） | |
std::hash為模板專門std::unique_ptr<T, Deleter>允許用戶獲取哈希的對象的類型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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對於一個給定的std::unique_ptr<T, Deleter> p，專業化，確保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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[编辑] 為例
#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'; }
Output:
Foo... hash(up): 3686401041 hash(foo): 3686401041 ~Foo...
[编辑] 另請參閱
| （C++11） |
hash function object （類模板） |
