.. _memory_pool_allocator_cls:
memory_pool_allocator
=====================
.. note::
To enable this feature, set the ``TBB_PREVIEW_MEMORY_POOL`` macro to 1.
A class template that provides a memory pool with a C++ allocator interface.
.. contents::
:local:
:depth: 1
Description
***********
``memory_pool_allocator`` meets the allocator requirements from the [allocator.requirements] ISO C++ Standard section
It also provides a constructor to allocate and deallocate memory.
This constructor is linked with an instance of either the ``memory_pool`` or the ``fixed_pool`` class.
The class is mainly intended for enabling memory pools within STL containers.
API
***
Header
------
.. code:: cpp
#include "oneapi/tbb/memory_pool.h"
Synopsis
--------
.. code:: cpp
namespace oneapi {
namespace tbb {
template<typename T>
class memory_pool_allocator {
public:
using value_type = T;
using pointer = value_type*;
using const_pointer = const value_type*;
using reference = value_type&;
using const_reference = const value_type&;
using size_type = size_t;
using difference_type = ptrdiff_t;
template<typename U> struct rebind {
using other = memory_pool_allocator<U>;
};
explicit memory_pool_allocator(memory_pool &pool) throw();
explicit memory_pool_allocator(fixed_pool &pool) throw();
memory_pool_allocator(const memory_pool_allocator& src) throw();
template<typename U>
memory_pool_allocator(const memory_pool_allocator<U,P>& src) throw();
pointer address(reference x) const;
const_pointer address(const_reference x) const;
pointer allocate(size_type n, const void* hint=0);
void deallocate(pointer p, size_type);
size_type max_size() const throw();
void construct(pointer p, const T& value);
void destroy(pointer p);
};
template<>
class memory_pool_allocator<void> {
public:
using pointer = void*;
using const_pointer = const void*;
using value_type = void;
template<typename U> struct rebind {
using other = memory_pool_allocator<U>;
};
memory_pool_allocator(memory_pool &pool) throw();
memory_pool_allocator(fixed_pool &pool) throw();
memory_pool_allocator(const memory_pool_allocator& src) throw();
template<typename U>
memory_pool_allocator(const memory_pool_allocator<U>& src) throw();
};
} // namespace tbb
} // namespace oneapi
template<typename T, typename U>
inline bool operator==( const memory_pool_allocator<T>& a,
const memory_pool_allocator<U>& b);
template<typename T, typename U>
inline bool operator!=( const memory_pool_allocator<T>& a,
const memory_pool_allocator<U>& b);
Member Functions
----------------
.. cpp:function:: explicit memory_pool_allocator(memory_pool &pool)
**Effects**: Constructs a memory pool allocator serviced by ``memory_pool`` instance pool.
-------------------------------------------------------
.. cpp:function:: explicit memory_pool_allocator(fixed_pool &pool)
**Effects**: Constructs a memory pool allocator serviced by ``fixed_pool`` instance pool.
Examples
********
The code below provides a simple example of container construction with the use of a memory pool.
.. code:: cpp
#define TBB_PREVIEW_MEMORY_POOL 1
#include "oneapi/tbb/memory_pool.h"
...
typedef oneapi::tbb::memory_pool_allocator<int>
pool_allocator_t;
std::list<int, pool_allocator_t> my_list(pool_allocator_t( my_pool ));
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