Date: Tue, 11 Nov 2014 16:31:05 +0000 From: Brooks Davis <brooks@freebsd.org> To: Dag-Erling Sm?rgrav <des@des.no> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, "Bjoern A. Zeeb" <bz@freebsd.org>, src-committers@freebsd.org, Bruce Evans <brde@optusnet.com.au> Subject: Re: svn commit: r274340 - in head/sys: crypto/rijndael dev/random geom/bde Message-ID: <20141111163105.GA69731@spindle.one-eyed-alien.net> In-Reply-To: <86oasd6dad.fsf@nine.des.no> References: <201411100944.sAA9icnN061962@svn.freebsd.org> <3C962D07-3AAF-42EA-9D3E-D8F6D9A812B0@FreeBSD.org> <86sihq5a2v.fsf@nine.des.no> <20141111223756.F3519@besplex.bde.org> <86oasd6dad.fsf@nine.des.no>
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[-- Attachment #1 --] On Tue, Nov 11, 2014 at 03:07:54PM +0100, Dag-Erling Sm?rgrav wrote: > Bruce Evans <brde@optusnet.com.au> writes: > > -Wcast-qual is not a very good warning option since the official way > > to remove qualifiers in C is to cast them away. Casting them away is > > better than using the __DECONST() abomination. The option exists > > because it is too easy for sloppy code to cast away const without > > really intending to or when casting away const is done intentionally > > but is an error. > > I agree that __DECONST() is ugly (not least because it strips all > qualifiers, not just const, so it should be DEQUAL()), but the > alternative is worse. In my experience, the majority of cases where a > cast discards a qualifier are bugs, with struct iov being one of very > few legitimate use cases. On the processor we (SRI and Cambridge) are working on, pointers are not integers (we support some integer behaviors, but not pointer->int->pointer casts except in limited cases) and the current __DECONST implementation will need to die[0]. For existing C versions some sort of compiler support for __DECONST is probably the right thing to do. In general, we need to fix the C/C++ standard to us express the things we actually mean when we use const (for example see strchr()'s use of const). I believe the last issue now being tracked on Google's internal list of deficiencies in the C++ standard. -- Brooks [0] The recently discussed _ALIGN also needs to die and be replaced with something that increments the pointer (or returns how much to increment) rather than jamming it though a long. [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlRiOcgACgkQXY6L6fI4GtTrRACfT999XBInar6dHmsmVrxRBx/f BF8AoN9pD0cIDbQn+7wpgyBqyMI/mwZD =qLQb -----END PGP SIGNATURE-----help
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