public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "bspencer at blackberry dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/99058] New: Consider adding a note about std::optional ABI break to the C++17 status table
Date: Wed, 10 Feb 2021 13:07:52 +0000	[thread overview]
Message-ID: <bug-99058-4@http.gcc.gnu.org/bugzilla/> (raw)

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99058

            Bug ID: 99058
           Summary: Consider adding a note about std::optional ABI break
                    to the C++17 status table
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: bspencer at blackberry dot com
  Target Milestone: ---

In this table

https://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html#status.iso.2017

the row labelled "Library Fundamentals V1 TS Components: optional" says it's
supported since "7.1" and references Note 1, but there's no mention of the ABI
break between 7.x and 8.x.

Perhaps I was misusing this table, but I interpreted "supported since 7.1" to
mean that if I compile against 7.1 headers, my code will remain ABI compatible
against future versions of the library _and_ other code compiled against future
versions of the headers.  This ABI break caught me by surprise, and even though
these versions are older now, it seems worthwhile to at least mention the break
in a note to help others.

BTW, this particular example also happens to come up as a question in Marshall
Clow's recent talk on the topic of standard library ABIs.  See
https://youtu.be/7RoTDjLLXJQ?t=3191

Thanks.

             reply	other threads:[~2021-02-10 13:07 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-10 13:07 bspencer at blackberry dot com [this message]
2021-02-10 18:49 ` [Bug libstdc++/99058] " redi at gcc dot gnu.org
2021-02-10 18:49 ` redi at gcc dot gnu.org
2021-02-10 19:44 ` bspencer at blackberry dot com
2021-02-10 21:58 ` redi at gcc dot gnu.org
2021-02-10 22:06 ` redi at gcc dot gnu.org
2021-02-10 22:17 ` redi at gcc dot gnu.org
2021-02-10 22:19 ` redi at gcc dot gnu.org
2021-02-11 13:45 ` bspencer at blackberry dot com
2021-02-11 17:28 ` cvs-commit at gcc dot gnu.org
2021-02-12 14:49 ` redi at gcc dot gnu.org
2021-03-29 20:02 ` cvs-commit at gcc dot gnu.org
2021-04-19  9:05 ` cvs-commit at gcc dot gnu.org
2021-04-19  9:08 ` cvs-commit at gcc dot gnu.org
2021-04-19  9:08 ` redi at gcc dot gnu.org

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=bug-99058-4@http.gcc.gnu.org/bugzilla/ \
    --to=gcc-bugzilla@gcc.gnu.org \
    --cc=gcc-bugs@gcc.gnu.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).