求助，程序该怎么理解？？？

云云嘟p9iGv · 发表于 2018-9-11 12:51:32

各位大神，请帮我读一下这个程序中的for语句怎么理解？？？void
pbuf_cat(struct pbuf *h, struct pbuf *t)
{
  struct pbuf *p;

  LWIP_ERROR("(h != NULL) && (t != NULL) (programmer violates API)",
         ((h != NULL) && (t != NULL)), return;);

  /* proceed to last pbuf of chain */
  for (p = h; p->next != NULL; p = p->next) {
/* add total length of second chain to all totals of first chain */
p->tot_len += t->tot_len;
  }
  /* { p is last pbuf of first h chain, p->next == NULL } */
  LWIP_ASSERT("p->tot_len == p->len (of last pbuf in chain)", p->tot_len == p->len);
  LWIP_ASSERT("p->next == NULL", p->next == NULL);
  /* add total length of second chain to last pbuf total of first chain */
  p->tot_len += t->tot_len;
  /* chain last pbuf of head (p) with first of tail (t) */
  p->next = t;
  /* p->next now references t, but the caller will drop its reference to t,
* so netto there is no change to the reference count of t.
*/
}