How to properly use `__attribute__((format (printf, x, y)))` for C11 U"unicode literals"?

Question

I'm porting an application from using char* for everything and everywhere to using UCS4 as it's internal Unicode representation. I use C11's U"unicode literals" for defining strings, which expand to arrays of char32_t, which are uint32_t essentially.

Problem is with properly annotating printf-like functions. As "format" is no longer char*, compiler refuses to compile it further, as well it won't be happy with char32_t * instead of char * for %s format, I suppose.

I don't depend on stdlib *printf family at all, so formatting is done purely by mine implementation.

What is correct solution for this, other than just disable this attribute altogether?

Answer 1

There is currently no way to do this in GCC. It is a known bug, see GCC bug 64862