On Tue, Sep 12, 2023 at 07:22:24PM +0300, Alexey Dobriyan wrote:
> __DECLARE_FLEX_ARRAY(T, member) macro expands to
> 
>       struct {
>               struct {} __empty_member;
>               T member[];
>       };
> 
> which is subtly wrong in C++ because sizeof(struct{}) is 1 not 0,
> changing UAPI structures layouts.

Looking at this again just now, what about using a 0-length array
instead of an anonymous struct?

https://godbolt.org/z/rGaxPWjef

Then we don't need an #ifdef at all...

        struct {
                int __empty_member[0];
                T member[];
        };

-Kees

-- 
Kees Cook

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