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Re: [csmith-dev] Pragma pack clang/gcc difference

On Sun, Aug 14, 2011 at 9:00 PM, John Regehr <regehr@cs.utah.edu> wrote:
Clang and GCC have different layouts when using #pragma pack
together with size 0 bitfields!

This is interesting.  I wonder if it's intended, a bug, or just something that nobody cares about?

This does not answer your question completely, but I understand that the pack pragma was originally a feature of Microsoft compilers. GCC implemented it, and when later Clang implementors noticed that there were differences between the GCC implementation and the original Microsoft one, they decided to retain compatibility with the Microsoft version, dropping compatibility with GCC. So at least Clang implementors know about this subtlety.