std::owner_hash
From cppreference.com
C++
Memory management library
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Defined in header <memory>
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struct owner_hash; |
(since C++26) | |
This function object provides owner-based (as opposed to value-based) hashing of both std::weak_ptr and std::shared_ptr
Nested types
| Nested type | Definition |
is_transparent
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unspecified |
Member functions
operator() |
calculates the hash of the shared-ownership pointer (function) |
std::owner_hash::operator()
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template
<
class T >
std::size_t operator( ) ( const std::shared_ptr <T> & key ) const noexcept ; |
(1) | (since C++26) |
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template
<
class T >
std::size_t operator( ) ( const std::weak_ptr <T> & key ) const noexcept ; |
(2) | (since C++26) |
Equivalent to return key.owner_hash();.
Parameters
| key | - | shared-ownership pointer to be hashed |
Return value
A hash value that is identical for any std::shared_ptr or std::weak_ptr
Notes
| Feature-test macro | Value | Std | Feature |
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__cpp_lib_smart_ptr_owner_equality |
202306L |
(C++26) | Enabling the use of std::shared_ptr and std::weak_ptr as keys in unordered associative containers
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See also
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(C++26)
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provides owner-based hashing of shared pointers (public member function of std::shared_ptr<T>) |
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(C++26)
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provides owner-based hashing of weak pointers (public member function of std::weak_ptr<T>) |