On Thu, 2018-10-11 at 21:13 +0200, Johannes Berg wrote: > > However, I have another trick: > > #define __NLA_ENSURE(condition) (0 * sizeof(struct { unsigned int x:1 - 2*!(condition);})) > > or, in this context, > > #define BUILD_BUG_ON_RET_ZERO(cond) (0 * sizeof(struct { unsigned int x:1 - 2*!(condition);})) Oops, I forgot to insert the second !, it must be #define BUILD_BUG_ON_RET_ZERO(cond) (0 * sizeof(struct { unsigned int x:1 - 2*!!(condition);})) johannes