std::aligned_union
From cppreference.com
| Defined in header
<type_traits>
|
||
| template< std::size_t Len, class... Types >
struct aligned_union; |
(since C++11) | |
Provides the member typedef type, which is a POD type of a size and alignment suitable for use as uninitialized storage for an object of any of the types listed in Types. The size of the storage is at least Len. std::aligned_union also determines the strictest (largest) alignment requirement among all Types and makes it available as the constant alignment_value.
If sizeof...(Types) == 0, the behavior is undefined.
Contents |
[edit] Member types
| Name | Definition |
type
|
the POD type suitable for storage of any type from Types
|
[edit] Helper types
| template< std::size_t Len, class... Types >
using aligned_union_t = typename aligned_union<Len,Types...>::type; |
(since C++14) | |
[edit] Member constants
| alignment_value
[static]
|
the strictest alignment requirement of all Types (public static member constant) |
[edit] Possible implementation
#include <algorithm> template <std::size_t Len, class... Types> struct aligned_union { static constexpr std::size_t alignment_value = std::max({alignof(Types)...}); struct type { alignas(alignment_value) char _s[std::max({Len, sizeof(Types)...})]; }; }; |
[edit] Example
| This section is incomplete Reason: no example |
[edit] See also
| (C++11)
|
obtains the type's alignment requirements (class template) |
| (C++11)
|
defines the type suitable for use as uninitialized storage for types of given size (class template) |