参考代码

 MemoryRegion(size_t size, size_t alignment = 0)
        : IMemoryRegion(size), _mem(nullptr), _ptr(nullptr)
    {
        if(size != 0)
        {
            // Allocate backing memory
            size_t space = size + alignment;
            _mem         = std::shared_ptr<uint8_t>(new uint8_t[space](), [](uint8_t *ptr)
            {
                delete[] ptr;
            });
            _ptr = _mem.get();

            // Calculate alignment offset
            if(alignment != 0)
            {
                void *aligned_ptr = _mem.get();
                std::align(alignment, size, aligned_ptr, space);
                _ptr = aligned_ptr;
            }
        }
    }

aligned_alloc

Defined in header <stdlib.h>

void *aligned_alloc( size_talignment, size_t size);
(since C11) |