说明：  这篇文章是dec公司底下的一个研究中心早期（1989年）提供的一份在c下如何实现exception handler.对于想了解c++异常处理具体原理及实现手段的朋友来说是不可多得的参考资料
(This article is dec companies a research center under the Early (1989) provided an in c how to realize exception handler. To want to know c++ Unusual deal with the specific principles and means to realize a friend is hard to come by reference)