aligned_storage
通过union 将存储和访问分开，并将存储数据的内存作为整体进行对齐
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| #include <vector>
#include <iostream>
#include <type_traits>
template <typename T>
using Vec = std::vector<T>;
template <typename T, size_t N>
struct GetAlignedData {
using type = typename std::aligned_storage<sizeof(T) * N, sizeof(T) * N>::type;
};
template <typename T, size_t N>
using AlignedType = typename GetAlignedData<T, N>::type;
template <typename T, size_t N>
union PackData {
AlignedType<T, N> storage;
T elem[N];
};
int main() {
PackData<int, 4> data;
int x[4] = {1, 2, 3, 4};
data.storage = *(reinterpret_cast <AlignedType<int, 4>* >(x));
for(auto z : data.elem) {
std::cout << "z: " << z << std::endl;
}
return 0;
}
|