please give me some advices.

I get a compile error,when to index on base class member.

struct Foo 

{ 

int a; 

}; 

 

struct Bar : public Foo 

{ 

int b;

}; 

struct idx0 {};

typedef multi_index_container<

Bar,

indexed_by<

 ordered_unique<

tag < idx0 > ,member < Bar,int,&Bar::a> 

 >

>

> test_type;

Error 1 error C2440: 'specialization' : cannot convert from 'int Foo::* ' to 'int Bar::* '

and the codes are compiled in boost 1.40, vs 2008 sp1