[Boost-users] [array] VC++ 7.1 bug and a proposed fix

5 Jul 2006

      The following code does not compile with VC++ 7.1 and Boost 1.33.1.
I believe the code should compile,
and that this is a VC++ 7.1 bug.

-----------------------------------------------------

#include <boost/array.hpp>
using boost::array;

struct X {
     array<int,4> f() { return array<int,4>(); }
};

template<class X, class T>
void g(X& x, T (X::*h)()) {}

void f() {
	X x;
	g(x, &X::f);
}

------------------------------------------------------

When I compile the code I get the bizarre error message

     error C2664: 'g' : cannot convert parameter 2 from
     'boost::array<T,N> (__thiscall X::* )(void)'
     to
     'boost::array<T,N> (__thiscall X::* )(void)'
     with [T=int,N=4] and [T=int, N=4]
     Types pointed to are unrelated;
     conversion requires reinterpret_cast,
     C-style cast or function-style cast

If I modify the array class by adding a non-templatized
assignment operator, as follows,
then the code does compile.

---------------------------------------------------------

namespace boost {
     template<class T, std::size_t N>
     class array {
         ...
         array<T,N>& operator=(const array<T,N>& rhs) {
             std::copy(rhs.begin(), rhs.end(), begin());
             return *this;
         }
         ...
     };
}

----------------------------------------------------------

So I propose that this assignment operator is added,
as a VC++ 7.1 bug workaround, to the array class.

I have contacted Nicolai Josuttis concerning this,
and he told me he is not maintaining the array library anymore.

--Johan Råde