[pjmlp]

Unless you can vouch for the C++ compiler, the best C++ portable code can offer today is C++17.

Also 8 and 16 bit embedded toolchains are certainly not on C11 / C17, they can hardly afford full C89.

[flohofwoe]

SDCC is a niche C compiler for 8-bit CPUs and is more uptodate than MSVC ;P

https://sdcc.sourceforge.net/

That's the nice thing with C: it's much easier for small teams to fully support than the latest C++ standards.

[pjmlp]

Now try to use it on the embedded deployments that require certification.