Re: [PATCH v5 9/9] bug.h, compiler.h: Introduce compiletime_assert & BUILD_BUG_ON_MSG

Daniel Santos
2012-11-16T23:25:12Z

On 11/13/2012 04:13 PM, danielfsantos@att.net wrote:
> +#define __compiletime_assert(condition, msg, __func) \
> + do { \
> + bool __cond = !(condition); \
> + extern void __func(void) __compiletime_error(msg); \
> + if (__cond) \
> + __func(); \
> + __compiletime_error_fallback(__cond); \
> + } while (0)
> +
> +#define _compiletime_assert(condition, msg, __func) \
> + __compiletime_assert(condition, msg, __func)
> +
> +/**
> + * compiletime_assert - break build and emit msg if condition is false
> + * @condition: a compile-time constant condition to check
> + * @msg: a message to emit if condition is false
> + *
> + * In tradition of POSIX assert, this macro will break the build if the
> + * supplied condition is *false*, emitting the supplied error message if the
> + * compiler has support to do so.
> + */
> +#define compiletime_assert(condition, msg) \
> + _compiletime_assert(condition, msg, __compiletime_assert_ ## __LINE__)
> +

Whoops, this implementation pastes the tokens before allowing them to
expand, it should be something like this:

#define __compiletime_assert(condition, msg, __func) .... stuff
#define _compiletime_assert(condition, msg, prefix, suffix) \
__compiletime_assert(condition, msg, prefix ## suffix)
#define compiletime_assert(condition, msg) \
_compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)

I'll fix that as well.

Daniel