Re: [boost] [Type Traits] Patch for type_with_alignment

From: Douglas Paul Gregor (gregod_at_[hidden])
Date: 2002-03-27 14:36:09

On Wed, 27 Mar 2002, Ralf W. Grosse-Kunstleve wrote:

> Currently I am using code from Andrei Alexandrescu for computing
> proper alignments for a fixed-capacity array type (see URL below).
> Here is the hook that I am using (in auto_allocator.h):
> 
>   template <typename T, std::size_t N>
>   union auto_allocator {
>     char buffer[N * sizeof(T)];
>     typename cctbx::af::alignment_calculator::AlignmentCalculator<
>       CCTBX_AF_TYPELIST1(T)>::Result dummy_;
>   };
> 
> And then (in small_plain.h):
>   
>   detail::auto_allocator<ElementType, N> m_elems;
> 
> Could I use type_with_alignment to achieve the same?
> 
> Does type_with_alignment or any other code that I would need
> for the auto_allocator depend on mpl?
> 
> Thanks,
>         Ralf

Yes, you can use type_with_alignment. Then auto_allocator would look like
this:

template<typename T, std::size_t N>
union auto_allocator {
  char buffer[N*sizeof(T)];
  typename boost::type_with_alignment<boost::alignment_of<T>::value>::type 
    dummy_;
};

The type_with_alignment code does not use MPL - it uses the Boost
Preprocessor library only.

        Doug