public inbox for gcc-prs@sourceware.org help / color / mirror / Atom feed
From: ljrittle@gcc.gnu.org To: andrew@andypo.net, gcc-bugs@gcc.gnu.org, gcc-prs@gcc.gnu.org, ljrittle@gcc.gnu.org, rodrigc@gcc.gnu.org Subject: Re: libstdc++/5432: Implementation still not thread-safe on multiprocessor machines Date: Thu, 24 Jan 2002 13:26:00 -0000 [thread overview] Message-ID: <20020124212600.20158.qmail@sources.redhat.com> (raw) Synopsis: Implementation still not thread-safe on multiprocessor machines State-Changed-From-To: analyzed->feedback State-Changed-By: ljrittle State-Changed-When: Thu Jan 24 13:25:59 2002 State-Changed-Why: Andrew, there were two minor issues with your patch: (And it took collective thought to figure all this out so don't feel bad. ;-) In general, static _Atomic_word should always be init'd to 0 with C++. We think g++ follows the init order rules of C which are tighter than C++ but for C++ non-zero static values may not be init'd until after main() has run (the only rule says it must be done "before the related block [scope] is entered" which might be after threads were started). Secondly: < if (--_M_references == 0) // XXX MT --- > if (__exchange_and_add(&_M_references, -1) == 1) is correct (you had == 0). I.e. assuming it was correct as written (other than thread-safety) your rewrite had a memory leak. Other than that, Nathan and I have reviewed the patch; I have tested it and installed it (that report to the libstdc++ mailing list). To be closed after you confirm MP *-*-linux* system fixed as installed and then I move it to 3.0.X branch. Thanks, Loren http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=5432
next reply other threads:[~2002-01-24 21:26 UTC|newest] Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top 2002-01-24 13:26 ljrittle [this message] -- strict thread matches above, loose matches on Subject: below -- 2002-02-18 15:46 Andrew Pollard 2002-02-17 18:54 rodrigc 2002-01-23 23:49 ljrittle 2002-01-19 7:26 andrew
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=20020124212600.20158.qmail@sources.redhat.com \ --to=ljrittle@gcc.gnu.org \ --cc=andrew@andypo.net \ --cc=gcc-bugs@gcc.gnu.org \ --cc=gcc-gnats@gcc.gnu.org \ --cc=gcc-prs@gcc.gnu.org \ --cc=rodrigc@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: linkBe 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).