std::hash

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Defined in header `<functional>`

template< class Key > struct hash;		(C++11 feature)

The hash template defines a hash function object such that if two objects K and M of the same type Key compare equal, then std::hash(K)==std::hash(M), although the reverse is not necessarily true.

The unordered associative containers std::unordered_set, std::unordered_multiset, std::unordered_map, std::unordered_multimap use specializations of the template std::hash as the default hash function.

Defined in header `<functional>`

template<> struct hash<bool>; template<> struct hash<char>; template<> struct hash<signed char>; template<> struct hash<unsigned char>; template<> struct hash<char16_t>; template<> struct hash<char32_t>; template<> struct hash<wchar_t>; template<> struct hash<short>; template<> struct hash<unsigned short>; template<> struct hash<int>; template<> struct hash<unsigned int>; template<> struct hash<long>; template<> struct hash<long long>; template<> struct hash<unsigned long>; template<> struct hash<unsigned long long>; template<> struct hash<float>; template<> struct hash<double>; template<> struct hash<long double>; template< class T > struct hash<T*>;

[edit] Standard specializations for library types

std::hash<std::string> std::hash<std::u16string> std::hash<std::u32string> std::hash<std::wstring> (C++11)
(C++11)
(C++11)
(C++11)

hash support for strings
(class template specialization)

std::hash<std::error_code> (C++11)

hash support for std::error_code
(class template specialization)

std::hash<std::bitset> (C++11)

hash support for std::bitset
(class template specialization)

std::hash<std::unique_ptr> (C++11)

hash support for std::unique_ptr
(class template specialization)

std::hash<std::shared_ptr> (C++11)

hash support for std::shared_ptr
(class template specialization)

std::hash<std::type_index> (C++11)

hash support for std::type_index
(class template specialization)

std::hash<std::vector<bool>> (C++11)

hash support for std::vector<bool>
(class template specialization)

std::hash<std::thread::id> (C++11)

hash support for std::thread::id
(class template specialization)


`argument_type`	`Key`

`result_type`	std::size_t

std::hash

From Cppreference

Contents

[edit] Member types

[edit] Member functions

[edit] Standard specializations for basic types

[edit] Standard specializations for library types