https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79301
--- Comment #5 from Anders Kaseorg <andersk at mit dot edu> --- (In reply to Jakub Jelinek from comment #4) > (In reply to Anders Kaseorg from comment #3) > > (In reply to Jakub Jelinek from comment #2) > > > I think right now you need to use > > > #ifdef __has_cpp_attribute > > > # if __has_cpp_attribute(fallthrough) >= __cplusplus > > > [[fallthrough]]; > > > > Surely you intended* #if __has_cpp_attribute(fallthrough) && __cplusplus >= > > __has_cpp_attribute(fallthrough)? > > No, I meant what I wrote. __has_cpp_attribute(fallthrough) gives you the > year + month when the feature has been introduced, and you then use it only > if it has been introduced before or at the same time as the C++ version > (__cplusplus gives you again year + month) you are compilining for. For the nonzero case, “before or at the same time” translates to <=, not >=.
