不必等候其他线程完成，当前线程就可以“帮助”它完成操作，把尾指针向前移动(B)。

Rather than wait for the other thread to finish, the current thread can "help" it out by finishing the operation for it by moving the tail pointer forward (b).

youdao

在静止状态时，尾指针指向的链接节点的next字段总为null，而在中间状态时，这个字段为非null。

In the quiescent state, the next field of the link node pointed to by the tail is always null; in the intermediate state, it is always non-null.

youdao

返回：若成功为指针，出错或文件尾为NULL ？

Returns: Pointer if OK, NULL on error or end of file?

youdao

通常使指针指向尾字节是不安全的。

It is usually unsafe to have a pointer to a trail byte.

youdao

通常使指针指向尾字节是不安全的。

It is usually unsafe to have a pointer to a trail byte.

youdao