scalable_allocator¶
[memory_allocation.scalable_allocator]
A scalable_allocator is a class template that models the allocator requirements from the [allocator.requirements] ISO C++ section.
The scalable_allocator allocates and frees memory in a way that scales with the number of processors.
Memory allocated by a scalable_allocator should be freed by a scalable_allocator, not by a std::allocator.
// Defined in header <oneapi/tbb/scalable_allocator.h>
namespace oneapi {
namespace tbb {
template<typename T> class scalable_allocator {
public:
using value_type = T;
using size_type = std::size_t;
using propagate_on_container_move_assignment = std::true_type;
using is_always_equal = std::true_type;
scalable_allocator() = default;
template<typename U>
scalable_allocator(const scalable_allocator<U>&) noexcept;
T* allocate(size_type);
void deallocate(T*, size_type);
};
} // namespace tbb
} // namespace oneapi
Caution
The scalable_allocator requires the memory allocator library. If the library is missing, calls to the scalable allocator fail. In
contrast to scalable_allocator, if the memory allocator library is not available, tbb_allocator falls back on std::malloc and std::free.
Member Functions¶
Non-member Functions¶
These functions provide comparison operations between two scalable_allocator instances.
namespace oneapi {
namespace tbb {
template<typename T, typename U>
bool operator==(const scalable_allocator<T>&,
const scalable_allocator<U>&) noexcept;
template<typename T, typename U>
bool operator!=(const scalable_allocator<T>&,
const scalable_allocator<U>&) noexcept;
} // namespace tbb
} // namespace oneapi
The namespace where these functions are defined is unspecified, as long as they may be used in respective binary operation expressions on scalable_allocator objects.
For example, an implementation may define the classes and functions in the same unspecified internal namespace,
and define oneapi::tbb::scalable_allocator as a type alias for which the non-member functions are reachable only via argument-dependent lookup.