On Mon, Oct 22, 2018 at 1:24 PM Miguel Ojeda <miguel.ojeda.sandonis@xxxxxxxxx> wrote: > > On Mon, Oct 22, 2018 at 12:53 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote: > > > > On Mon, Oct 22, 2018 at 2:41 AM, Miguel Ojeda > > <miguel.ojeda.sandonis@xxxxxxxxx> wrote: > > > > > * clang does *not* support the attribute in C. > > > > Well that's not good. :) > > I will see with clang if they plan to add it. > So I have looked in the clang sources and I have seen that clang is already preparing for C2x: since clang >= 6 we can actually enable the C++-like attributes with "-fdouble-square-bracket-attributes" in C mode, which in turn makes the warning work in C mode and can be suppressed with [[fallthrough]]. This would give us the warning also in clang, which would be a win vs. the comments. Nick? However, I don't see a way to enable [[fallthrough]] in C mode for gcc >= 7.1 -- from a quick look, the C parser does not know about [[]] attributes, so I don't think we can use [[fallthrough]] for both compilers (yet). Cheers, Miguel