> Now your index variable is signed, which can cause problems when used in expressions due to C's conversion rules.

I don't see this. What problems would those be?

> ssize_t is a POSIX thing so you'd have to define it yourself on windows.

True. But I think "int" would be the right choice anyway in almost all case.

> If your type is 32 bit, you run into promotion problems and might even run into truncation problems.

What promotion problems? If your loop exceeds 2G than yes, you run into overflow (not for backwards loop though). But with a signed type you can automatically get a trap or diagnostic for overflow. This is far easier to debug and protect against compared to mistakes with unsigned types.