On July 31, 2019 11:48:32 AM PDT, Peter Zijlstra <pet...@infradead.org> wrote: >On Wed, Jul 31, 2019 at 11:24:36AM -0700, h...@zytor.com wrote: >> >> > +/* >> >> > + * Add the pseudo keyword 'fallthrough' so case statement >blocks >> >> > + * must end with any of these keywords: >> >> > + * break; >> >> > + * fallthrough; >> >> > + * goto <label>; >> >> > + * return [expression]; >> >> > + * >> >> > + * gcc: >>https://gcc.gnu.org/onlinedocs/gcc/Statement-Attributes.html#Statement-Attributes >> >> > + */ >> >> > +#if __has_attribute(__fallthrough__) >> >> > +# define fallthrough >__attribute__((__fallthrough__)) >> >> > +#else >> >> > +# define fallthrough do {} while (0) /* >fallthrough */ >> >> > +#endif >> >> > + > >> If the comments are stripped, how would the compiler see them to be >> able to issue a warning? I would guess that it is retained or >replaced >> with some other magic token. > >Everything that has the warning (GCC-7+/CLANG-9) has that attribute.
The standard is moving toward adding this as an attribute with the [[fallthrough]] syntax; it is in C++17, not sure when it will be in C be if it isn't already. -- Sent from my Android device with K-9 Mail. Please excuse my brevity.
