Problem with Generic pointers

Helo !!!
I was trying to implement linked list in which the data field is
Generic...
the structure details are..

typedef struct node
{
         void *data;
         struct node *next;

}gnode;

Now to add a node into it, and i have written this function.

void insert(gnode **head,void *data,unsigned int size)
{
         gnode *temp;
         int i=0;
         temp=(gnode *)malloc(sizeof(gnode));
         temp->data=malloc(size);
         for(int i=0;i<size;i++)
                 *(char *)(temp->data+i) = *(char *)(data + i);

         temp->next= (*head);
         (*head)=temp;

}

Well i dont know how to copy the data into the temp->data.
But I have written the following code...

for(int i=0;i<size;i++)
                 *(char *)(temp->data+i) = *(char *)(data + i);

But it is giving the error : ' void * ' : Unknown size .

If anyone knows any other way of copying it please tell me. And please
help me out in finding what is happening wrong in this code.
Thanks

If I want to use the same logic, then do you know about any solution.

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