The abstract reads:
In our Formalin project to formalize C11 (the ANSI/ISO standard of the C programming language) we discovered many subtleties that make formalization of this standard difficult. We discuss some of these subtleties and indicate how they may be addressed in a formal C semantics.
Furthermore, we argue that the C standard does not allow Turing complete implementations, and that its evaluation semantics does not preserve typing. Finally, we claim that no strictly conforming programs exist. That is, there is no C program for which the standard can guarantee that it will not crash.