Rethink exception handling at C level

Exception handling is one of the most complex and advanced language features, and is found in most modern languages. However, it's hard, if not impossible, to teach exception mechanism and its implementation techniques well to undergraduates without the necessary language background, due to the complex dynamic nature of exceptions. This paper presents a novel methodology to teach exception handling by rethinking exception handling and its semantics at C level. The key novelty is that the exception handling is implemented totally at C level, and the standard implementation technique of stack unwinding is also modeled honestly at C level. The main technical advantage is that students can master all these facets with the minimal requirement. Our teaching experience shows success of this methodology and students can understand the main techniques more easily than in traditional ways.