template class within another : problem with gcc 3.2.3 on linux (BUG ??)

[corey taylor]

Suresh,

  What type of objects are contained_size and inner_object?

corey

On 6/20/05, Suresh T <suresh.t@philips.com> wrote:
> hi,
> 
> I need to use a template class object  within another template class.
> Specifically gcc (3.2.3 on linux) gives me a problem when the INNER
> TEMPLATE OBJECT IS CREATED USING THE TEMPLATE PARAMETER OF THE ENCLOSING
> CLASS and when i call the inner class object function from the  enclosing
> class object function..
>  AS this works fine in MS VC7 so i wanted to know if this is some bug in
> gcc
> 
> Example :
> In the below example the "enclosing" class contains an object of
> "contained" class. The  contained object is  created using the
> template  parameter of "enclosing" class. When the "enclosing" class
> function is called, we call the function of the inner object.
> 
> template <std::size_t size>
> class contained {
>    public:
>          template <std::size_t sub_size>
>          int   func_inner(){   ...  }
> 
> };
> 
> template < std::size_t  size>
> class enclosing {
> 
>      public:
> 
>      template <std::size_t sub_size>
>       int   func_enclose(){   ...
> 
>            return
>             (static_cast<contained_size>( inner_object) ) .fun_inner();
>                                                                        //
> =================THIS GIVES AN ERROR         ========================
> MARK1
>        }
> 
>       contained<size> inner_object;      //   ============== THIS IS THE
> ORIGIN OF ERROR ? =====================      MARK2
> 
> };
> 
> 
> Note : The error disappears if i use a specific value when creating the
> inner_object ( MARK 2 above)
> That is instead of   "contained<size> inner_object" if i use "contained <N>
> inner_object" where N is any number like 32.
> (Even in that case i need to use a static_cast ( see MARK 1) to remind the
> compiler of the data type of inner_object otherwise
> the compiler gives an error which i find strange.)
> 
> I cant use a specific value for the inner object as it should take it from
> the enclosing class template parameter. Since this is
> not working i would greatly appreciate if someone can tell me whether this
> is a gcc bug or if i need to do something special to let the compiler
> know what i am trying to do.
> 
> Thanks &
> ---------------------------------------------------------------------------------------------------------
> 
> Warm Regards,
> Suresh.T
> 
> 
>