Great that setjmp/longjmp is explicit, and that in C there are even more liberties to cast away const than in C++, while some surprises in embedded, when the compiler decides const could have been placed into read only memory.
I don't know why you are now jumping to setjmp/longjmp, trying to make a point that somehow C is the worst programming languages ever, when all I am trying to argue is for sane programming practices, hinting that more complex features (line especially found in newer languages) are not solutions but part of the complexity problem.