From: Jody Hagins (jody-boost-011304_at_[hidden])
Date: 2005-03-01 12:54:56
On Tue, 1 Mar 2005 09:31:21 -0800 (PST)
Chris Just <cpjust_at_[hidden]> wrote:
> I'm using MS Visual C++ 6.0. This is what I'm doing:
Sorry ;-)
> CBase { ... };
> CDerived : public CBase { ... };
>
> CSomething
> {
> public:
> CSomething( const CBase& base ) : m_Base( base ) {}
>
> CSomething& operator=( const CSomething& rhs )
> {
> if ( typeid( m_Base ) != typeid( rhs.m_Base ) ) // This never
> fails.{
> throw exception();
> }
> }
>
> private:
> CBase& m_Base;
> };
>
> When I look at the type_info object's name(), it always returns
> "CBase", even if it's actually a CDerived object.
You have ommitted the most important pieces in your code sample...
#include <typeinfo>
#include <cassert>
struct np_base { };
struct np_derived : public np_base { };
struct base { virtual ~base() { } };
struct derived : public base { };
int main(int, char *[])
{
np_derived npd;
derived d;
np_base * np_base_ptr = &npd;
base * base_ptr = &d;
assert(typeid(*np_base_ptr) == typeid(np_base));
assert(typeid(*base_ptr) == typeid(derived));
return 0;
}
Compile and run the above on your compiler. If it fails, you have a
problem with your compiler. Otherwise, you probably have a problem with
your code. Note that you only get the most derived type, if the class
is polymorphic (i.e., has at least one virtual function).