Re: [RFC PATCH] compiler_attributes.h: Add 'fallthrough' pseudo keyword for switch/case use

[Pavel Machek <pavel@ucw.cz>]

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On Tue 2019-07-30 22:35:18, Joe Perches wrote:
> Reserve the pseudo keyword 'fallthrough' for the ability to convert the
> various case block /* fallthrough */ style comments to appear to be an
> actual reserved word with the same gcc case block missing fallthrough
> warning capability.

Acked-by: Pavel Machek <pavel@ucw.cz>

> +/*
> + * 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
> +

Will various checkers (and gcc) recognize, that comment in a macro,
and disable the warning accordingly?

Explanation that the comment is "magic" might not be a bad idea.

Thanks,

									Pavel

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