Difference between revisions of "cpp/memory/allocation result"
From cppreference.com
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{{ddcl | header=memory | since=c++23 | | {{ddcl | header=memory | since=c++23 | | ||
| − | template< class Pointer, class SizeType > | + | template< class Pointer, class SizeType = std::size_t > |
struct allocation_result { | struct allocation_result { | ||
Pointer ptr; | Pointer ptr; | ||
Revision as of 03:10, 27 February 2023
| Defined in header <memory>
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(since C++23) | |
allocation_result specializations are returned from the allocate_at_least member function of appropriate Allocator types (e.g. std::allocator::allocate_at_least) and std::allocator_traits::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.
Contents |
Template parameters
| Pointer | - | typically std::allocator_traits<Alloc>::pointer, where Alloc is an Allocator type
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| SizeType | - | typically std::allocator_traits<Alloc>::size_type, where Alloc is an Allocator type
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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
Pointer and SizeType are a pointer to an object type and std::make_unsigned_t<std::ptrdiff_t> (which is almost always same as std::size_t) by default.
| Feature-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_allocate_at_least |
202106L | (C++23) |
Example
| This section is incomplete Reason: no example |
See also
| (C++23) |
allocates uninitialized storage at least as large as requested size (public member function of std::allocator<T>)
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| [static] (C++23) |
allocates storage at least as large as the requested size via an allocator (public static member function of std::allocator_traits<Alloc>)
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