std::allocation_result

 

C++

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Dynamic memory management

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Uninitialized memory algorithms uninitialized_copy uninitialized_fill uninitialized_move (C++17) uninitialized_default_construct (C++17) uninitialized_value_construct (C++17) destroy (C++17) destroy_at (C++17) uninitialized_copy_n (C++11) uninitialized_fill_n uninitialized_move_n (C++17) uninitialized_default_construct_n (C++17) uninitialized_value_construct_n (C++17) destroy_n (C++17) construct_at (C++20) Constrained uninitialized memory algorithms ranges::uninitialized_copy (C++20) ranges::uninitialized_fill (C++20) ranges::uninitialized_move (C++20) ranges::uninitialized_default_construct (C++20) ranges::uninitialized_value_construct (C++20) ranges::destroy (C++20) ranges::destroy_at (C++20) ranges::uninitialized_copy_n (C++20) ranges::uninitialized_fill_n (C++20) ranges::uninitialized_move_n (C++20) ranges::uninitialized_default_construct_n (C++20) ranges::uninitialized_value_construct_n (C++20) ranges::destroy_n (C++20) ranges::construct_at (C++20) Garbage collection support declare_reachable (C++11)(until C++23) undeclare_reachable (C++11)(until C++23) declare_no_pointers (C++11)(until C++23) undeclare_no_pointers (C++11)(until C++23) pointer_safety (C++11)(until C++23) get_pointer_safety (C++11)(until C++23) Miscellaneous pointer_traits (C++11) to_address (C++20) addressof (C++11) align (C++11) assume_aligned (C++20) C Library malloc aligned_alloc (C++17) calloc realloc free Low level memory management operator new operator new[] operator delete operator delete[] get_new_handler set_new_handler bad_alloc bad_array_new_length nothrow_t align_val_t destroying_delete_t new_handler nothrow

 

Defined in header <memory>
template< class Pointer > struct allocation_result {     Pointer ptr;     std::size_t count; };		(since C++23)

allocation_result specializations are return types of the allocate_at_least member function of appropriate Allocator types (e.g. std::allocator::allocate_at_least) and std::allocate_at_least.

Every specialization of allocation_result has no base classes or declared members other than ptr and count, thus it is suitable for aggregate initialization and structured binding.

Template parameters

Pointer

-

typically std::allocator_traits<Alloc>::pointer, where Alloc is an Allocator type

Member objects

ptr (C++23)	typically used for the address of the first element in the storage allocated by allocate_at_least (public member object)
count (C++23)	typically used for the actual number of elements in the storage allocated by allocate_at_least (public member object)

Notes

Feature-test macro:

__cpp_lib_allocate_at_least

See also

allocate_at_least (C++23)	allocates uninitialized storage at least as large as requested size (public member function of std::allocator<T>)
allocate_at_least (C++23)	allocates storage at least as large as the requested size via an allocator (function template)