That's one of the problems that original BeOS had -- they were locked into gcc 2.95 abi. In the late days of BeOS, gcc 3 was released and it was not possible to use it.

I also think C++ is uniquely bad for this. There are maybe other languages that would fare better, perhaps even C.

For example, CoreFoundation has a C API... that would be a bit of a test of a C-only framework world.

You can see however that's missing the convenience of Obj-C.

I hope Swift will be successful. It is nice to use (most of the time).

The same problem we have now with Swift. Even after ABI stability code compiled and linked across different versions don't often work.