pfil_list_t
pfil_list_t *newlist, *oldlist;
memcpy(newlist, oldlist, sizeof(pfil_list_t));
pfil_list_t *oldlist, *newlist;
pfil_list_t *phlist;
pfil_list_t *phlist;
pfil_list_t *active; /* lists[0] or lists[1] */
pfil_list_t lists[2];