线程应该以到达scoped_lock构造函数的顺序来获取锁(我认为).但是并不能保证他们会以任何固定顺序到达这一点！

The threads should acquire the lock in the same order that they reach the scoped_lock constructor (I think). But there's no guarantee that they will reach that point in any fixed order!

因此，一般来说:不要依赖它.

So in general: don't rely on it.