Supporting the oldest form doesn't seem to be a priority for a warning - if you have a very old codebase, probably not worth building it with warnings enabled. Updating code to use more modern/idiomatic forms is within scope for Clang's warnings, within reason, I think.
- Dave On Fri, Dec 28, 2018 at 1:26 PM Jay K via cfe-users < cfe-users@lists.llvm.org> wrote: > This is an old topic: > > > http://clang-developers.42468.n3.nabble.com/Warray-bounds-seems-over-zealous-on-Clang-td3162669.html > > But some points were left not covered. > > 1. "code hygiene" I'd say is that, the code should > just be portable to "all" compilers, and have the same meaning > with all of them, with a minimum of ifdefs. > > 2. Furthermore, regarding "same meaning" to all of them, > there are these choices: > > typedef struct A1 { > int a; > int b[0]; > } A1; > > typedef struct A2 { > int a; > int b[]; > } A2; > > typedef struct A3 { > int a; > int b[1]; > } A3; > > int a1 = sizeof(A1); > int a2 = sizeof(A2); > int a3 = sizeof(A3); > > They are all valid with clang and probably gcc. > But they are not likely all valid with additional compilers and through > time. > [1] seems like the most portable and oldest form, and might as well just > keep using it indefinitely. > > But it gets a warning. > If one were to ifdef clang to avoid it, one would lose interopation across > compilers, as > the various forms do not have the same meaning. > Everyone would have to compile with the same compiler/defines. > Else the types would vary in size. > > So I come back to believing that the best choices are either: > - do not warn for size=1 at end of aggregate > - possibly a separate setting for specifically that > > That is what gcc does also it appears (both). > > I ran across all this exact situation -- ifdef gnuc/clang in some code, > with comment that everyone has to compile the same, chosing between 0 and 1 > for zero sized array. > > > Thank you, > - Jay > _______________________________________________ > cfe-users mailing list > cfe-users@lists.llvm.org > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-users >
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