20 Memory management library [mem]

20.4 Memory resources [mem.res]

20.4.2 Class memory_resource [mem.res.class]

20.4.2.3 Private virtual member functions [mem.res.private]

virtual void* do_allocate(size_t bytes, size_t alignment) = 0;
Preconditions: alignment is a power of two.
Returns: A derived class shall implement this function to return a pointer to allocated storage ([basic.stc.dynamic.allocation]) with a size of at least bytes, aligned to the specified alignment.
Throws: A derived class implementation shall throw an appropriate exception if it is unable to allocate memory with the requested size and alignment.
virtual void do_deallocate(void* p, size_t bytes, size_t alignment) = 0;
Preconditions: p was returned from a prior call to allocate(bytes, alignment) on a memory resource equal to *this, and the storage at p has not yet been deallocated.
Effects: A derived class shall implement this function to dispose of allocated storage.
Throws: Nothing.
virtual bool do_is_equal(const memory_resource& other) const noexcept = 0;
Returns: A derived class shall implement this function to return true if memory allocated from *this can be deallocated from other and vice-versa, otherwise false.
[Note 1: 
It is possible that the most-derived type of other does not match the type of *this.
For a derived class D, an implementation of this function can immediately return false if dynamic_cast<const D*>(&other) == nullptr.
— end note]