Compiler engineer Marek Polacek of Red Hat recently proposed making the C++20 language specification (or rather the GNU++20 dialect) the default C++ version when not otherwise specified.
Polacek proposed declaring GCC’s C++20 support no longer experimental and to use it as the default. The current default dialect is C++17 (GNU++17) that was set five years ago.
Polacek commented in his mailing list proposal:
“I had been hoping to move to C++20 in GCC 15 (see bug 113920), but at that time libstdc++ still had incomplete C++20 support and the compiler had issues to iron out (mangling of concepts, modules work, etc.). Are we ready now? Is anyone aware of any blockers? Presumably we still wouldn’t enable Modules by default.
I’m willing to do the work if we decide that it’s time to switch the default C++ dialect (that includes updating cxx-status.html and adding a new caveat to changes.html).”
So far no firm activity around this C++20 proposal. With GCC 16 shifting to stage three development next week, it may be too late for this change to happen with the GCC 16 compiler release due out in the early months of 2026, but we’ll see.
