Re: [boost] Re: Formal Review in progress

From: Peder Holt (peder.holt_at_[hidden])
Date: 2005-05-27 04:47:28

On 5/27/05, Alexander Nasonov <alnsn-boost_at_[hidden]> wrote:
> Arkadiy Vertleyb <vertleyb <at> hotmail.com> writes:
> 
> > I think they are:
> >
> > template<class T>
> > char foo(vector<T>& v)[id1][id2][id3];
> >
> > But how would this work?  This array type will stay inside the function.
> 
> #include <boost/mpl/assert.hpp>
> #include <boost/mpl/equal.hpp>
> #include <boost/mpl/vector_c.hpp>
> 
> char (&foo())[9][8][7][6];
> 
> int main()
> {
>     using namespace boost::mpl;
> 
>     typedef vector_c<
>         int
>       , sizeof(foo())          / sizeof(foo()[0])
>       , sizeof(foo()[0])       / sizeof(foo()[0][0])
>       , sizeof(foo()[0][0])    / sizeof(foo()[0][0][0])
>       , sizeof(foo()[0][0][0]) / sizeof(foo()[0][0][0][0])
>       > vec;
> 
>       BOOST_MPL_ASSERT(( equal< vec, vector_c<int,9,8,7,6> > ));
> }
> 
> Sizes may become very huge, though.

If you replace your function with:
char (&foo())[900][800][700][600];
you will get an overflow when calculating e.g. sizeof(foo()) /
sizeof(foo()[0]),
and the result will be garbage.

> 
> > We need a function to return the object of certain _size_
> > in order to pass it outside...
> 
> I don't understand it.
> 
> --
> Alexander Nasonov
> 
> _______________________________________________
> Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
>