I don't doubt the C99 committee did a fantastic job maintaining backward compatibility with extant code-bases which use ill- or un-defined semantics of older standards. But I don't think that the success of the committee at doing its job necessarily redeems C99 as a semantically sane language -- indeed, I would argue that the need for design-by-committee is indicative of the hefty baggage of backward-compatibility issues which necessitates such convoluted semantics and boxes the C language into a linguistic dead-end.