https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90081
--- Comment #6 from Harald van Dijk <harald at gigawatt dot nl> --- (In reply to Guy Perfect from comment #5) > (In reply to Harald van Dijk from comment #4) > That was my line of thinking: supplying a cast in the macro. Keep in mind that inside #if expressions, there cannot be and will not be any cast. That's the reason I included the + there. > Even in the > case of negative values being cast to unsigned types, the language spec > provides a rule for that, so the behavior is defined independent of the > implementation: As Andreas Schwab pointed out, the behaviour of UINT8_C in that case is undefined, even if the behaviour of a cast would be defined. It simply does not matter what happens in that case. > I think the ticket was marked "resolved invalid" prematurely, as there's > clearly a meaningful problem and a meaningful solution. I do think it's rightly closed, but for a reason not yet mentioned: these macros are not defined by GCC's <stdint.h>. If this required compiler magic to implement, it would be primarily a GCC bug, but the fact that no compiler magic is needed means this is purely a glibc bug, so should be filed there.
