On 2012.12.04 23.24, Sebastian Andrzej Siewior wrote: > > VLAIS is not something they are willing to accept (for various > > reasons). There are other patches to LLVM that are still working > Is this not described in C99 6.7.2.1p16? No, this is not the case - flexible array members are a very different beast, which are in-and-of-themselves of debatable merit. C99 6.7.2.1p8 explicitly states that VLAIS are illegal. The same language is present in C11 (same section): A member of a structure or union may have any object type other than a variably modified type. In C99 6.7.5.1p3, the definition of a variably modified type is given: .. [snip] ... If the nested sequence of declarators in a full declarator contains a variable length array type, the type specified by the full declarator is said to be variably modified. It would require incredible, earth-moving acts for VLAIS to become a part of the ISO/IEC standard for the C programming language. P.S. As a general note, while I do agree that it is preferable to rewrite code using VLAIS instead of utilizing a macro, I would ask that some reconsideration be given, unless there are Linux kernel developers who are willing and able to implement the necessary rewrites. The LLVMLinux project does not wish to decrease the code quality of the Linux kernel, and certainly we do not intend to cause any GCC breakage. However, I think that rewrites to all the relevant VLAIS code would be quite time consuming for the LLVMLinux team, and the proposed macro does not appear to me to present any particular evil, other than by nature of being a macro. If faced between the choice of either accepting this VLAIS patch, or not being able to compile the Linux kernel with standard-compliant, largely GCC-compatible compilers such as Clang and icc, I would think that accepting the VLAIS patch would be preferable. (note also that I have only come in on the end of this thread, and I may have missed part of the context). -- Bryce Adelstein-Lelbach aka wash STE||AR Group, Center for Computation and Technology, LSU -- 860-808-7497 - Cell 225-578-6182 - Work (no voicemail) -- stellar.cct.lsu.edu boost-spirit.com llvm.linuxfoundation.org --
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