This would break legacy code. I had one employer with a bool type that was a 32-bit integer because of obscure alignment issues. This is why _Bool exists and the bool typedef has to be brought in explicitly with stdbool. You can't just go and usurp popular short type names. The standard reserved *_t and _[A-Z].+ for this purpose. People have been writing portable code with the expectation that future standards aren't going violate that promise and break things.