On Thu, Sep 20, 2012 at 2:57 PM, Marshall Clow <[email protected]>wrote:

> On Sep 17, 2012, at 5:35 PM, Joseph Galbraith <[email protected]>
> wrote:
>
> > Building wake.cpp with clang and -std=c++11 -stdlib=libc++ generates
> errors do narrowing.  I believe the following patch is the right way to fix
> these.  Any chance of getting this applied (or something else that makes it
> build out of the box) ?
>
> This patch bothers me.
> I (think I) understand the problem, and the rationale for the fix.
>
> But there's some subversion of the type system going on here, and it might
> be better to fix that, rather than continue it.
>
> To summarize:
>         int arr [] = {
>                 0x12345678,
>                 0x89ABCFEF
>                 };
>
> Both of the values in the array are actually unsigned, and have to be
> (implicitly) converted to int.
> When compiling for c++11, clang (rightly) complains that 0x89ABCFEF is
> bigger than the maximum number representable by an int.
>
> Changing the type of the array to "unsigned int" (or just unsigned)
> removes the compile-time error - but does it change the algorithm?
>
>
> -- Marshall
>
> Marshall Clow     Idio Software   <mailto:[email protected]>
>
> A.D. 1517: Martin Luther nails his 95 Theses to the church door and is
> promptly moderated down to (-1, Flamebait).
>         -- Yu Suzuki
>


There is more to the clang/cryptopp compile errors found here --
http://sourceforge.net/apps/trac/cryptopp/ticket/17

This is not totally related but if you are using clang with libc++ then you
will find this useful.

I think if somebody could run the clang static_analysis on cryptopp and
attend to some of the actual positives that it throws up it would be great.
(hint hint !!)

I agree with Marshal in this case the risk to the algorithm does exist with
the change (risk, not proven) but with static analysis there is many more
obvious issues.

David

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