On Thu, Mar 04, 2010 at 05:26:02PM -0500, Greg A. Woods wrote:
> > No such luck, at least not until C grows a stronger type system. See
> > for example strchr(3).
>
> I don't think a stronger type system would really change this issue
> fundamentally unless it was one which was so radical as to change the
> entire language -- All that may really be needed is a new kind of
> qualifier, one that tells the compiler a return value (or other internal
> variable) has the same "const" status as some given input parameter
> ("const_if_{parameter-name}_const" or some such similar nonsense).
That *is* a stronger type system, one with parametric polymorphism for
type qualifiers.
> While strchr()'s interface, and that of strrchr() of course, are indeed
> excellent examples this issue, the use of __UNCONST() within their
> implementation to hide silly warnings that might be encountered by
> compiling their implementations doesn't really "fix" anything except the
> silly warnings. The code _must_ do what it _should_ not do. :-)
Well right...
> And so I think what I said about __UNCONST() being unnecessary
> remains.
...but that makes it necessary. At least given the concept of
"necessary" that I'm familiar with :-)
--
David A. Holland
dholl...@netbsd.org
