Function listJoin

app/redis-6.2.6/src/adlist.c:362–378

Add all the elements of the list 'o' at the end of the * list 'l'. The list 'other' remains empty but otherwise valid. */

/* Add all the elements of the list 'o' at the end of the
 * list 'l'. The list 'other' remains empty but otherwise valid. */
void listJoin(list *l, list *o) {
    if (o->len == 0) return;

    o->head->prev = l->tail;

    if (l->tail)
        l->tail->next = o->head;
    else
        l->head = o->head;

    l->tail = o->tail;
    l->len += o->len;

    /* Setup other as an empty list. */
    o->head = o->tail = NULL;
    o->len = 0;
}