Hi! https://en.cppreference.com/w/c/compiler_support has a table with compiler support for C23. I've added #embed and [[unsequenced]]/[[reproducible]] in there yesterday, but am wondering about the accuracy of the rest.
Given the switch to -std=gnu23 preparation, I wonder what is still unimplemented in GCC 15. The cppreference page mentions as unimplemented on the GCC side N2653 - Type change of u8 string literals and as only partially implemented N2341 - IEEE 754 decimal floating-point types N2601 - IEEE 754 interchange and extended types N2900 - Empty initializers N2934 - New spelling of keywords N3033 - __VA_OPT__ with following comments in the wiki source: N2341: Only TR 24732 mentioned; some requirements in core language missing N2601: Only TS 18661-3 mentioned; the status of conformance is unknown N2900: missing support for scalars and VLAs Are some of the papers/features known to be fully implemented (since which version)? E.g. for __VA_OPT__ I remember doing (and Jason too) various fixes in the past few years, like PR89971, PR103415, PR101488. Not really sure what exactly C23 requires. Jakub