Hello. Generally speaking, I wonder what version of LLVM is used as a "base" in the latest Keil? I think I looked into the third_party_licenses.txt file and saw a line there Clang v3.7.0 [UV4\UVCC.dll]. At the same time, on the site https://releases.llvm.org/ the latest version is 19.1.0, in which I hope to see support for C23. Apparently, Keil fans will not see support for C23 in their projects anytime soon?
There is a macro __VERSION__ that defines this.
https://developer.arm.com/documentation/101754/0623/armclang-Reference/Other-Compiler-specific-Features/Predefined-macros
Checking Arm Compiler for Embedded 6.22, I see this is Clang 19.0.0git.
Regards, Ronan