C certainly gives the illusion of portability. I recall a fellow who worked on DSP programming, where chars and shorts and ints and longs were all 32 bits. He said C was great because that would compile.

I suggested to him that he'd have a hard time finding any existing C code that ran correctly on it. After all, how are you going to write a byte to memory if you've only got 32 bit operations?

Anyhow, after 20 years of programming C, I took what I learned and applied it to D. The integral types are specified sizes, and 2's complement.

One might ask, what about 16 bit machines? Instead of trying to define how this would work in official D, I suggested a variant of D where the language rules were adapted to 16 bits. This is not objectively worse than what C does, and it works fine, and the advantage is there is no false pretense of portability.