@陈梓瀚(vczh)
标准说了：
As control passes from a throw-expression to a handler, destructors are invoked for all automatic objects constructed since the try block was entered. The automatic objects are destroyed in the reverse order of the completion of their construction.
实现上一边unwinding一边找catch没问题吧。过阵子较闲了再来看看
具体实现吧。 :)