@FortranFan, perhaps, you should familiarize yourself with the gfortran manual.
@kargl, please don’t say such things in this forum, because it can be seen as disrespectful (we have a Code of Conduct at this forum: Welcome to Discourse) and it assumes that @FortranFan fan is not familiar with the GFortran manual, which is an incorrect assumption (@FortranFan is very much familiar with the GFortran manual), but even if that was correct, you can say the same thing respectfully, for example you can say something like:
“@FortranFan, I think this is explained in the GFortran manual, in particular you can try adding the -Wall option. …”