GCC 16 considering changing default to C++20

Summary

From: Marek Polacek <polacek@redhat.com> To: GCC <gcc@gcc.gnu.org>, Jonathan Wakely <jwakely@redhat.com>, Jason Merrill <jason@redhat.com> Subject: Change the default C++ dialect to gnu++20 Date: Mon, 3 Nov 2025 13:34:28 -0500 [thread overview] Message-ID: <aQj1tKzhftT9GUF4@redhat.com> (raw) I would like us to declare that C++20 is no longer experimental and change the default dialect to gnu++20. Last time we changed the default was over 5 years ago in GCC 11: <https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=0801f419440c14f6772b28f763ad7d40f7f7a580> and before that in 2015 in GCC 6.1, so this happens roughly every 5 years. 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). Marek next reply other threads:[~2025-11-03 18:34 UTC|newest] Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top 2025-11-03 18:34 Marek Polacek [this message] 2025-11-17 11:10 ` Jason Merrill 2025-11-17 11:17 ` Jakub Jelinek 2025-11-17 12:53 ` Jason Merrill 2025-11-17 12:59 ` Iain Sandoe Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=aQj1tKzhftT9GUF4@redhat.com \ --to=polacek@redhat.com \ --cc=gcc@gcc.gnu.org \ --cc=jason@redhat.com \ --cc=jwakely@redhat.com \ ...