Re: [Boost-users] [multi_index] multi index container with Managed C++

From: Parag Gadkari (parag.gadkari_at_[hidden])
Date: 2006-04-12 16:45:36

Joaquin,
The key extractor along with the unmanaged wrapper lets the MC++ use B.MI

Thanks
--Parag
--------------------------------------------------------------
typedef gcroot<employer *> _hdl_employer;

struct wrapGC {
    int idx;
    _hdl_employer _gc_hdl;
    wrapGC(employer *e):_gc_hdl(e) {
    }

};
struct get_Id {
    typedef int result_type;
    result_type operator()(const wrapGC* w_e) const {
        employer *gc_e = w_e->_gc_hdl;
        return gc_e->get_DrawingId();
    }
};
typedef multi_index_container<
  wrapGC*,
  indexed_by<
      ordered_non_unique<get_Id>
    >
  > employee_set;

On 4/7/06, Parag Gadkari <parag.gadkari_at_[hidden]> wrote:
>
> Thanks Joaquin,
> I will try it out, I really got frustated with Managed C++ 'cause it was
> not allowing me to use stl and boost containers with the managed objects.
> Its actually because the GC has to shuffle the objects around so its not
> possible to get the address of member variable and/or proc.
>
> I guess what I have to do is write a nogc wrapper just like what you have
> pointed out and use pinned pointers.
>
> Regards
> Parag
>
>
> On 4/7/06, Joaquín Mª López Muñoz <joaquin_at_[hidden]> wrote:
>
> >
>
> Parag Gadkari ha escrito:
>
> I am having trouble while using multi index container with the "managed
> c++" component. Here is the typedef that the compiler won't accept.
>
>
> typedef
> multi_index_container<
>   gcroot<interface_entity*>,
>
>   indexed_by<    ordered_unique<
> identity<gcroot<interface_entity*> > >,
>     ordered_non_unique
> <member<gcroot<interface_entity*>
> , int,&interface_entity::entity_drawingid> >,
>   >> entity_collection;
>
> The real deal is with the member template which needs the address of
> member variable of the interface_entity class. Entity class is an abstract
> Managed type (specified with __gc), and it is not allowed to take the
> address of a non-static member of a managed type.
>
> Does anybody know of a workaround?
>
>
> Hello Parag,
>
> A simple solution is to write a custom key extractor as described at:
>
> http://tinyurl.com/l3g6u
>
> In your particular case, the extractor would look like the following
> (warning, uncompiled):
>
> struct entity_drawingid_extractor
> {
>   typedef int result_type;
>
>   result_type operator()(const gcroot<interface_entity*>& x)const
>   {
>     return x->entity_drawingid;
>   }
> };
>
> Does this help? Is this the only problem you've stumbled upon when
> using B.MI with Managed C++? I'm curious as reports of usage of
> Boost libs in .NET C++-like languages are scarce.
>
> Joaquín M López Muñoz
> Telefóinca, Investigación y Desarrollo
>
>
>
> _______________________________________________
> Boost-users mailing list
> Boost-users_at_[hidden]
> http://lists.boost.org/mailman/listinfo.cgi/boost-users
>
>
>

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