https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70529
--- Comment #8 from Manuel López-Ibáñez <manu at gcc dot gnu.org> --- (In reply to Axel Naumann from comment #2) > You asked for it, so here is my wish list: > - for C++ < 1z, do not support hexfloats, neither with "unsigned" not > negative exponents. Since "unsigned" exponents are supported by standard C++11, g++ has to support them. > Or support both, as a GCC extention that's enabled by > default - like in the GCC 5 times. Given Joseph comments, it seems the "signed" extension is incompatible with standard C++ < 1z. That is, the same valid program may behave differently whether the extension is enabled or not. > - if you remove support for C++ < 1z, state that hexfloats are unsupported > in C++ < 1z. Only "signed" exponents are unsupported. My patch above tries to catch this case and give a better error message, but it is not as trivial as I thought. > NB: Even if I would buy into the argument that diagnostics are limited by > the tokens, I don't yet see why 'P' ends up being concated to the pp-number > token in C++ < 1z. You have to run g++ (actually, cc1plus) under a debugger to see why. See lex_number. Doing it in a different way would probably break a lot of other things.
