[chaoky]

I think you're confusing syntax and semantics. The claim is that C is not really semantically well defined, but your toplevel posts talk about the fact that C has well defined syntax, which is true. However, that's besides the point. Syntax is roughly the surface form, whereas semantics refers to meaning. The problem is that a well formed program (ie a syntactically correct program; this is actually the precise definition of well-formed) in C yields undefined behavior on a semantic level, exactly what we don't want to happen. You need to maintain a clear separation between the syntax and meaning. When parent said that its legal C, he meant syntactically. The point is by definition you cannot tell from the surface/lexical form of C what is semantically valid and what is not semantically valid, ie what is well defined and what is not. So by saying its undefined behavior you are proving parent's point, that a syntactically valid piece of C yields a semantically not well defined chunk of code.