On Tue, Nov 11, 2014 at 03:07:54PM +0100, Dag-Erling Sm?rgrav wrote: > Bruce Evans <b...@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.
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