In otherwords there isn't a way to easily make your own character in C++
That seems like the truth!
Especially since C++ is just a tool that interfaces with other systems, I suppose there's no direct way c++ itself could create a character the system would recognize! It would probably have to be the other way around (make some kind of program that the OS can use to map numbers to additional characters then make a C++ implementation that makes the mapping easier?).
It's just a theory, but that's the way I'd assume it would work out.