20 Memory management library [mem]

20.4 Memory resources [mem.res]

20.4.5 Pool resource classes [mem.res.pool] Members [mem.res.pool.mem]

void release();
Effects: Calls upstream_resource()->deallocate() as necessary to release all allocated memory.
[Note 1: 
The memory is released back to upstream_resource() even if deallocate has not been called for some of the allocated blocks.
— end note]
memory_resource* upstream_resource() const;
Returns: The value of the upstream argument provided to the constructor of this object.
pool_options options() const;
Returns: The options that control the pooling behavior of this resource.
The values in the returned struct may differ from those supplied to the pool resource constructor in that values of zero will be replaced with implementation-defined defaults, and sizes may be rounded to unspecified granularity.
void* do_allocate(size_t bytes, size_t alignment) override;
Effects: If the pool selected for a block of size bytes is unable to satisfy the memory request from its own internal data structures, it will call upstream_resource()->allocate() to obtain more memory.
If bytes is larger than that which the largest pool can handle, then memory will be allocated using upstream_resource()->allocate().
Returns: A pointer to allocated storage ([basic.stc.dynamic.allocation]) with a size of at least bytes.
The size and alignment of the allocated memory shall meet the requirements for a class derived from memory_resource ([mem.res.class]).
Throws: Nothing unless upstream_resource()->allocate() throws.
void do_deallocate(void* p, size_t bytes, size_t alignment) override;
Effects: Returns the memory at p to the pool.
It is unspecified if, or under what circumstances, this operation will result in a call to upstream_resource()->deallocate().
Throws: Nothing.
bool do_is_equal(const memory_resource& other) const noexcept override;
Returns: this == &other.