I read https://benjaminjurke.com/content/articles/2015/compile-time-numerical-unit-dimension-checking/#c11-string-literals
But it didn’t help much.
Where can I find related tutorials?
You should never use getValue(). You should always use convert(). Internally, it uses SI units, but you should not have to think of that. To convert, you use this syntax: .convert(meter) or .convert(mps).
There is a literal for _meter2, or you can do meter * meter.