https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113873
Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |diagnostic Component|c++ |preprocessor --- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Can you provide an exact commands you used to compile? Main here is pointing to the main source file that is being compiled. Maybe the warning could be slightly clearer but it is basically saying you can't use it outside of a header file that is being `#include`d.