[Tinyos-devel] copying non nx_structs into messages

[David Gay]

On 7/27/07, Kevin Klues <klueska at gmail.com> wrote:
> Is there a convenient way to copy the contents of a non nx-type struct
> into a message payload?
>
> i.e. I have a struct defined
> typedef struct my_struct {
>   uint16_t a;
>   uint16_t b;
>   uint16_t c;
> } my_struct_t;
>
> and I want to copy it into the payload of a message whose data members
> must all be nx types.  Normally I would use something like memcopy,
> but this doesn't work when copying from a non-nx type structure into
> an nx-type one.
>
> Do I have to create a duplicate of my struct specifically for casting
> the payload of a message to and then copy everything element by
> element?
>
> i.e.
>   typedef nx_struct nx_my_struct {
>   uint16_t a;
>   uint16_t b;
>   uint16_t c;
> } nx_my_struct_t;
>
> message_t msg;
>
> event void MyRead.readDone(my_struct_t* data, error_t error) {
>   nx_my_struct_t* data_msg = call AMSend.getPayload(&msg);
>   data_msg->a = data->a;
>   data_msg->b = data->b;
>   data_msg->c = data->c;
>   //Doesn't work -- memcpy(data_msg, data, sizeof(my_struct_t));
> }

Yes.

David Gay