Messages in this thread | | | From | Rusty Russell <> | Subject | Re: [PATCH] utilize _Static_assert() for BUILD_BUG_ON() when the compiler supports it | Date | Mon, 05 Nov 2012 12:49:11 +1030 |
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Jan Beulich <JBeulich@suse.com> writes: > This makes the resulting diagnostics quite a bit more useful. > > Signed-off-by: Jan Beulich <jbeulich@suse.com>
Nice. I'm a bit disappointed we can't just treat _Static_assert() as void, like:
#define BUILD_BUG_ON_ZERO(e) (_Static_assert(!(e), "!(" #e ")"), 0)
> @@ -54,6 +61,15 @@ struct pt_regs; > */ > #ifndef __OPTIMIZE__ > #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)])) > +#elif __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3) > +#define __build_bug_on_failed(n) __build_bug_on_##n##_failed > +#define _BUILD_BUG_ON(n, condition) \ > + do { \ > + extern void __compiletime_error(#condition) \ > + __build_bug_on_failed(n)(void); \ > + if (condition) __build_bug_on_failed(n)(); \ > + } while(0) > +#define BUILD_BUG_ON(condition...) _BUILD_BUG_ON(__COUNTER__, ##condition) > #else > extern int __build_bug_on_failed; > #define BUILD_BUG_ON(condition) \
Why does this depend on gcc version? Looks like residue from an attempt to use _Static_assert here?
Thanks, Rusty.
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