scanon added inline comments.
================ Comment at: lib/Headers/float.h:137 +#ifdef __STDC_WANT_IEC_60559_TYPES_EXT__ +# define FLT16_MANT_DIG __FLT16_MANT_DIG__ ---------------- rogfer01 wrote: > scanon wrote: > > rogfer01 wrote: > > > My understanding is that, given that we support TS18661-2 by default, > > > this macro should be predefined by clang and then there is no need to > > > protect these macros. > > > > > > You may want to add a test for this in `test/Preprocessor/init.c`. > > Where do you see that the `__STDC_WANT_IEC_60559_TYPES_EXT__` macro should > > be predefined by clang? > Hi Steve, > > certainly you're right, the TS says > > > The new identifiers added to C11 library headers by this part of ISO/IEC > > TS-18661 are defined or declared by their respective headers only if > > `__STDC_WANT_IEC_60559_TYPES_EXT__` is defined as a macro at the point in > > the source file where the appropriate header is first included. > > so (if I read this right) these identifiers are only available if such macro > is defined when including `float.h`. > > Can I assume from your comment that someone else should define it? Perhaps > the `float.h` header itself, some other file in the C-library implementation > or the user of the compiler via some `-D__STDC_WANT_IEC_60559_TYPES_EXT__`, > but not be predefined by the compiler? If this is the case, then the macros > still have to be guarded conditionally (as they were in the original patch). > > Does this make sense? Thanks. I think we could justify defining it ourselves under non-strict compilation modes; alternatively, system headers might define it for users in non-strict modes. My reading of the TS is that in strict mode, these types and macros should be hidden unless the user explicitly requests them by defining `__STDC_WANT_IEC_60559_TYPES_EXT__` themselves. https://reviews.llvm.org/D34695 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
