The legitimate difference between C and C++ ABIs is that the C ABI is easier to understand and reason about.
It's analogous to Java and Scala; each has an ABI, but it's easier to tell when the former breaks ABI than the latter.
It's analogous to Java and Scala; each has an ABI, but it's easier to tell when the former breaks ABI than the latter.
There is a difference, but the difference is in complexity, not availability.