[boost] Re: Re: Is there any way to get typeid() to return the derived class name?

From: Chris Just (cpjust_at_[hidden])
Date: 2005-03-01 12:31:21

Jody Hagins wrote:
>> I've been looking through the boost library and I haven't been able to
>> find anything that works like typeid() that returns the exact (i.e.
>> derived) class name instead of just the base class.
>> I want to compare two derived classes to make sure that they are of
>> the same class, but typeid() only returns the name of the base class.
>> 
>> If there is a boost function that does this, or if someone has a way
>> of doing it could you please point me in the right direction?
>
> Funny about timing...
>
> I think I can answer your question, but I must answer with another
> question.  What do you mean by "typeid() only returns the name of the
> base class?"  This is surely not the case for polymorphic types, at
> least according to the standard.  Maybe if you post a bit of code, which
> represents what you are trying to accomplish, I can help...

I'm using MS Visual C++ 6.0.  This is what I'm doing:

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.

                
__________________________________ 
Do you Yahoo!? 
Yahoo! Mail - now with 250MB free storage. Learn more.
http://info.mail.yahoo.com/mail_250