I am mixing and matching C/C++ in a single project. Whilst gcc recognises _Decimal64 as a built-in type, g++ does not. Is there a way that I can cajole g++ into recognising it, and "doing the right thing"?
NB I cannot used the C++ std::decimal type, as that would introduce incompatabilities with C interoperability.
The other direction might be easier. If you put wrappers around the functions that need it, you could convert from this to doubles in the C code and call it with doubles from C++, maybe?