#include <stdio.h>
struct my_struct {
     int a, b;
};
#define EVEN_INLIST_GET(Inlist) (& ((Inlist)->even))
#define EVEN_INLIST_CONTAINER_GET(ptr, type) \
   ((type *)((char *)ptr - offsetof(type, even)))
int
main(void)
{
   struct my_struct *d, *cur;
   int i;
   for (i = 0; i < 100; i++)
     {
        d = malloc(sizeof(*d));
        d->a = i;
        d->b = i * 10;
        if ((i % 2) == 0)
     }
   printf("list=%p\n", list);
     printf("\ta=%d, b=%d\n", cur->a, cur->b);
   printf("list_even=%p\n", list_even);
   for (itr = list_even; itr != NULL; itr = itr->next)
     {
        cur = EVEN_INLIST_CONTAINER_GET(itr, struct my_struct);
        printf("\ta=%d, b=%d\n", cur->a, cur->b);
     }
   itr = list_even;
   while (itr)
     {
        cur = EVEN_INLIST_CONTAINER_GET(itr, struct my_struct);
        if ((cur->a % 3) == 0)
        itr = next;
     }
   while (list)
     {
                                                          struct my_struct);
        free(aux);
     }
   return 0;
}