Go原子/线程中的append（）安全吗？

Reading through a couple of lists I want to add all lines from each list into one big array. I run each list reader in it's own goroutine. Can I just append a line as soon as it's read?

Is this thread save or can this explode in my hand?

type listHolder {
  entries []entry
}

func (h *listHolder) readAllLists(s []list) {
  c := make(chan list)
  var wg sync.WaitGroup

  for _, l := range s {
    wg.Add(1)
    go h.readSomeList(&wg, l)
  }

  c.close()
  wg.Wait()  
}

func (h *listHolder) readSomeList(wg *sync.WaitGroup, l list) {
  defer wg.Done()
  for e := range extractEntry(l) {
    h.entries = append(h.entries, newEntry(e))
  }
}

Something like this would be ok. Or you might like to think up a different architecture, such as using a channel to feed the updates to a single go routine

type listHolder {
  entries []entry
  m sync.Mutex
}

func (h *listHolder) readAllLists(s []list) {
  c := make(chan list)
  var wg sync.WaitGroup

  for _, l := range s {
    wg.Add(1)
    go h.readSomeList(&wg, l)
  }

  c.close()
  wg.Wait()  
}

func (h *listHolder) readSomeList(wg *sync.WaitGroup, l list) {
  defer wg.Done()

  for e := range extractEntry(l) {
    h.m.Lock()
    h.entries = append(h.entries, newEntry(e))
    h.m.Unlock()
  }
}