Be careful: They did not say that C is not Turing complete. They say that the C Standard does not define a language which is Turing complete. There is a subtle distinction between these two statements, but an important one. The larger point that the paper is making is that the C Standard is full of holes. Thus as a programmer you cannot rely on any compiler that implements this &quot;standard&quot; to do anything (even trivial things like allocate enough memory on the stack). Yes, it probably will work most of the time, but will it work always? No, well, then it&#x27;s not much of a standard, more of a set of loose guidelines. If you want to write secure, performant portable code: you need an actual standard. I think this is the point that the paper is making. Better still, it is highlighting the places where the standard is poorly defined so that it could be fixed.