c - 对齐 C 动态内存中数组的开头

Question

Possible Duplicate:
Aligned memory management?

我有一个数组，我这样声明

int * myarray;
int num_of_element;

myarry = (int*) calloc(num_of_elements, sizeof(int));

int 的大小是 4 个字节，但是我想确保我的数组从 8 个字节边界开始 - 这样我每次都可以有效地加载两个值。有什么不同的方法或其他我可以做的事情吗？

Answer 1

您尝试过posix_memalign吗？

The function posix_memalign() allocates size bytes and places the address of the allocated memory in *memptr. The address of the allocated memory will be a multiple of alignment, which must be a power of two and a multiple of sizeof(void *).

示例:

if (posix_memalign(&myarray, 8, num_of_elements*sizeof(int)) != 0) {
    // failed
}

参见http://pubs.opengroup.org/onlinepubs/009696699/functions/posix_memalign.html

Linux posix_memalign 手册页还记录了aligned_alloc() (c11)、memalign()(已过时):

https://www.kernel.org/doc/man-pages/online/pages/man3/posix_memalign.3.html