https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87161
--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Nir Aizik from comment #3) > I think what make it counter-intuitive is that warning from valid option the > order of Werror is not important Warnings from the code can't be emitted until compilation starts, and all options have to be processed before that starts. The -Werror has already been seen before compilation starts, so warnings have been turned into errors by the time compiler warnings are emitted. > Another thing that is troubling is when there is 2 Werror, before and after, > it will output only warning > > g++ -c -Werror -Wmissing-prototypes -Werror test.cpp -o test.o > cc1plus: warning: command line option ‘-Wmissing-prototypes’ is valid for > C/ObjC but not for C++ That's weird, yes. I think when there are duplicates only the last one has an effect, and so the first one (before the invalid -Wmissing-prototypes) is ignored.
