Defined in header <memory_resource> | ||
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template< class T > class polymorphic_allocator; | (since C++17) |
The class template std::pmr::polymorphic_allocator is an Allocator whose allocation behavior depends on the memory resource it is constructed with. Thus, different instances of polymorphic_allocator can exhibit entirely different allocation behavior. This runtime polymorphism allows objects using polymorphic_allocator to behave as if they used different allocator types at run time despite the identical static allocator type.
| Member type | definition |
|---|---|
value_type | T |
Constructs a polymorphic_allocator (public member function) |
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| (destructor)
(implicitly declared) | Implicitly declared destructor (public member function) |
| operator=
[deleted] | Copy assignment operator is deleted (public member function) |
Public member functions |
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| Allocate memory (public member function) |
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| Deallocate memory (public member function) |
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| Constructs an object in allocated storage (public member function) |
|
| Destroys an object in allocated storage (public member function) |
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Create a new polymorphic_allocator for use by a container's copy constructor (public member function) |
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| Returns a pointer to the underlying memory resource (public member function) |
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compare two polymorphic_allocators (function) |
polymorphic_allocator does not propagate on container copy assignment, move assignment, or swap. As a result, move assignment of a polymorphic_allocator-using container can throw, and swapping two polymorphic_allocator-using containers whose allocators do not compare equal results in undefined behavior.
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(C++17) | an abstract interface for classes that encapsulate memory resources (class) |
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