Making a deep-copy of a struct to a struct array in nesC (similar to C)

Question

I tried to look for an answer that could help me to solve my question but I couldnt really solve it by myself. So here it goes. I am programming in nesC which is similar to C.

I am trying to make deepcopies of a struct v inside specific locations of a struct array. The struct v is defined as follows:

struct ip_iovec v = {
  .iov_next = NULL,
  .iov_base = payload,
  .iov_len  = len,
};

where ip_iovec is defined as:

struct ip_iovec {
uint8_t         *iov_base;
size_t           iov_len;
struct ip_iovec *iov_next;
};

For this, I created a struct array of the same type:

struct ip_iovec buffer_v[2]; 

Now, I would like to deepcopy v into the 2nd position of my buffer_v array. For this I tried to do

buffer_v[1] = v;
buffer_v[1].iov_next = v.iov_next;
buffer_v[1].iov_base = v.iov_base;
buffer_v[1].iov_len = v.iov_len;

and also tried

memcpy(&buffer_v[0], &v, sizeof(struct ip_iovec));

but none of this worked. Additionally, I would like to copy the value from position 1 to position 0 in my array:

buffer_v[0] = buffer_v[1] (1)

and use the struct value from position 0:

value = &buffer_v[0] (2)

Since the function which is defining v is being called after (1) and (2) are performed, its value is rewritten, and that is why I would like to deepcopy it. When I say that the above operations didnt work I mean that when v changes, the value in buffer_v[0] also changes, which shouldnt be happening if I would be doing a correct deepcopy.

Thanks a lot for the help!

Answer 1

What do you mean by "worked"? How do you check this?

To copy a structure, just use assignment, no fanciness needed:

buffer_v[0] = v;

of course, if v has pointers and you don't want to copy the pointer values, i.e. having the copy point at the same data, you need to allocate space for new data and copy the data over, too. Since you don't show the actual declaration of struct ip_iovec it's hard to help with that.