Date: Sat, 10 Oct 2009 21:20:48 +0300 From: Kostik Belousov <kostikbel@gmail.com> To: Alex Goncharov <alex-goncharov@comcast.net> Cc: Dag-Erling =?koi8-r?B?U23DuHJncmF2?= <des@des.no>, stef@memberwebs.com, simon@freebsd.org, freebsd-hackers@freebsd.org Subject: Re: Is the FreeBSD ABI compatibility policy documented anywhere Message-ID: <20091010182048.GD2259@deviant.kiev.zoral.com.ua> In-Reply-To: <E1MwgPL-000Neg-W2@daland.home> References: <4ABBD5FA.5070507@memberwebs.com> <20091010142758.GB1225@arthur.nitro.dk> <86d44vp415.fsf@ds4.des.no> <E1MwgPL-000Neg-W2@daland.home>
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--ikjtAgnMx2oLjqdX Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sat, Oct 10, 2009 at 02:11:07PM -0400, Alex Goncharov wrote: > ,--- You/Dag-Erling (Sat, 10 Oct 2009 19:11:50 +0200) ----* > | "Simon L. Nielsen" <simon@FreeBSD.org> writes: > | > It's not entirely that simple. The ABI on a stable branch like 7.x > | > should be backward compatible, but there isn't a guarantee of forward > | > compatibility. IE, 7.0 binary should be able to run on 7.x, but a 7.2 > | > binary might not run on 7.0. It should be more or less the same with > | > the API's. > |=20 > | Correct, but we're getting closer to that now that we have symbol > | versioning - although we won't reach 100% until we have versioned > | symbols in *all* libraries, which is currently not the case. Even then, > | a developer might break the ABI by mistake, but hopefully we'd catch > | that before it made it into a release. >=20 > It's important to note that symbol compatibility is not the whole > thing -- the behaviour on exceptions may be equally important to some > applications. E.g. CMUCL code has to handle different ways to notify > of memory protection failures this way: >=20 > #if __FreeBSD_version < 700004 > #define PROTECTION_VIOLATION_SIGNAL SIGBUS > #define PROTECTION_VIOLATION_CODE BUS_PAGE_FAULT > #else > #define PROTECTION_VIOLATION_SIGNAL SIGSEGV > #define PROTECTION_VIOLATION_CODE SEGV_ACCERR > #endif >=20 > A CMUCL binary built on a pre-7.1 (?) release of FreeBSD, will crash > almost immediately when run on 7.1 (well, "if memory serves"). This has been an issue for 7.0, and it was explicitely handled, see r174254. --ikjtAgnMx2oLjqdX Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (FreeBSD) iEYEARECAAYFAkrQ0H8ACgkQC3+MBN1Mb4j0/QCgmO6ebLZv2r+7EXnXQXA/MMRA Ye0AoK+fpUt2MJctQ/tEvt3mm4VzIyk5 =IagP -----END PGP SIGNATURE----- --ikjtAgnMx2oLjqdX--
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