LLVM Clang 11 Adds -std=c++20 Support

With C++20 now being deemed complete from the recent ISO C++ meeting in Prague, the GNU Compiler Collection went ahead and added the -std=c++20 flag where as up until that change this weekend relied upon the -std=c++2a switch. LLVM's Clang compiler now has similar treatment on its codebase.

Like GCC, the LLVM Clang C++20 support isn't yet complete but it's working towards that milestone. But with C++20 now deemed complete and set to formally be out in the coming months during the 2020 year, the developers are comfortable exposing it now as -std=c++20 as the target. Additionally, LLVM Clang has shifted its C++2A references in their code-base to C++20. The old C++2A switch will still be an accepted argument for compatibility purposes.

The change along with updating __cplusplus for C++20 was committed on Tuesday for LLVM Clang 11.

The Clang C++ status page shows the imminent LLVM Clang 10 as supporting more of C++20 concepts, designated initializers, constinit, and other bits, but there still is more to support of the updated C++ language. Among the areas left are finishing up concepts, immediate functions, C++ modules, and other features.