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

From: Johan Råde (rade_at_[hidden])
Date: 2006-07-24 09:12:47

AlisdairM wrote:
> Johan Råde wrote:
> 
> 
>> 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.
> 
> The problem with that workaround is that the array template would no
> longer produce aggregate types, and we would lose the ability to use
> brace initialization:
> 
> std::tr1::array< int, 4 > x = { 0, 1, 2, 3 };
> 

Are you sure? An aggregate can not have user defined constructors,
but I believe user defined assignment operators ar OK.

I tested with VC++ 7.1, and there my fix can be combined with aggregate 
initialization.
(If I add a constructor though, then aggregate initialization does not 
work with VC++ 7.1.)

So I think my fix works.

> i/ does it fail on other compilers?
> ii/ Is it a very specific failure with pointer-to-member, or the first
> hint of a more general issue that should be solved?

I have no idea. The error only seems to pop up in fairly complex 
situations with templates and pointer-to-members.