Re: [boost] [multi_index] invalid expression as template parameter

From: Joaquín Mª López Muñoz (joaquin_at_[hidden])
Date: 2006-05-22 10:58:40

Tal Agmon ha escrito:

> Hello,
>
> I use multi_index as follow with success:
>
> typedef boost::multi_index::multi_index_container<
>                   boost::shared_ptr<NodeBase>,
>                   boost::multi_index::indexed_by<
>                   boost::multi_index::ordered_unique<
>                           BOOST_MULTI_INDEX_CONST_MEM_FUN(NodeBase, handle, getHandle)
>                         >,
>                   boost::multi_index::ordered_non_unique<
>                           BOOST_MULTI_INDEX_CONST_MEM_FUN(NodeBase, group_id, memberOf)
>                         >
>                   >
>                 > NodePtrSet;
>
> but I would like NodeBase inherite boost::enable_shared_from_this<NodeBase>
> I get error C2964: invalid expression as template parameter using msvc 6
>
> any idea?

Hello Tal,

Some more context is needed: the following complete snippet compiles and works
fine in MSVC 6.5, so your problem must depend on some other circumstance that
you haven't described sufficiently:

******** BEGIN CODE ********
#include <boost/multi_index_container.hpp>
#include <boost/multi_index/ordered_index.hpp>
#include <boost/multi_index/mem_fun.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/enable_shared_from_this.hpp>

typedef int handle;
typedef int group_id;

struct NodeBase:boost::enable_shared_from_this<NodeBase>
{
  NodeBase(handle h,group_id gid):h(h),gid(gid){}

  group_id memberOf()const{return gid;}
  handle   getHandle()const{return h;}

private:
  group_id gid;
  handle   h;
};

typedef boost::multi_index::multi_index_container<
  boost::shared_ptr<NodeBase>,
  boost::multi_index::indexed_by<
    boost::multi_index::ordered_unique<
      BOOST_MULTI_INDEX_CONST_MEM_FUN(NodeBase,handle,getHandle)
    >,
    boost::multi_index::ordered_non_unique<
      BOOST_MULTI_INDEX_CONST_MEM_FUN(NodeBase,group_id,memberOf)
    >
  >
> NodePtrSet;

int main()
{
  NodePtrSet ns;

  typedef boost::shared_ptr<NodeBase> element_type;

  ns.insert(element_type(new NodeBase(0,0)));
  ns.insert(element_type(new NodeBase(1,0)));
  ns.insert(element_type(new NodeBase(2,1)));

  return 0;
}

******** END CODE ********

Could you maybe come up with a reproducible test case showing the problem?

Best regards,

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo