Having worked at four places that have used #cplusplus, I now have a nugget of wisdom worth considering if you're in a position to hire engineers and are on a C++ project.

C++ is wide enough that it's a "dialect-y" language. I've worked at places that used macros and places that banned them. I've worked at places that relied on exceptions and places that forbade them in all contexts except the ones the compiler forces upon you. I've worked in places that are comfortable with the implicit casting rules and places that are hyper-paranoid and require you to use `explicit` everywhere and eschew default operator implementations.

Point is: if you interview someone for a C++ project and their résumé says they know C++, they probably don't know *your* C++ and that might introduce friction. Multiply your ramp-up time estimates appropriately.