一个简单的标记回收内存垃圾清理实现

[shuxiang1990]

源代码来自：https://github.com/munificent/mark-sweep
贴个别人的源代码主要是想问个问题，里面有这样一个函数：

void sweep(VM* vm)
{
  Object** object = &vm->firstObject;
  while (*object) {
    if (!(*object)->marked) {
      /* This object wasn't reached, so remove it from the list and free it. */
      Object* unreached = *object;

      *object = unreached->next;
      free(unreached);

      vm->numObjects--;
    } else {
      /* This object was reached, so unmark it (for the next GC) and move on to
       the next. */
      (*object)->marked = 0;
      object = &(*object)->next;
    }
  }
}

那地方虽然unreached空间被释放了，但是前一个节点不会留下悬挂指针吗？

[「已注销」]

不会。 因为他使用的就是前一个节点的指针，仔细看代码，object**