find out which C++ standard version was selected on the command line

We want to make some code that can look at which c++ standard was specified on the command line. Our looking didn't seem to show a predefined value for this. Where is this defined?

tia,

jerry

The __cplusplus preprocessor macro can be used to detect which C++ standard is in use ( see: https://en.cppreference.com/w/cpp/preprocessor/replace and https://renenyffenegger.ch/notes/development/languages/C-C-plus-plus/preprocessor/macros/predefined/__cplusplus )