RTTI

[Neo]

Hi Friends,
I have a question about RTTI.
1) In C++ we have vptr pointing to vtables which helps to make use of
pointer as polymorphic entities.
2) Without knowing object type I can call methods of object using
those pointers.
So in which case RTTI is needed? ( Why I need to know my object
type?)

Regards,
Neo

 

[Carlos Martinez]

Hi Friends,
I have a question about RTTI.
1) In C++ we have vptr pointing to vtables which helps to make use of
pointer as polymorphic entities.
2) Without knowing object type I can call methods of object using
those pointers.
So in which case RTTI is needed? ( Why I need to know my object
type?)

Regards,
Neo

For example: safe downcasting of polimorphic types

dynamic_cast uses RTTI

 

[Rolf Magnus]

Hi Friends,
I have a question about RTTI.
1) In C++ we have vptr pointing to vtables which helps to make use of
pointer as polymorphic entities.

We might. The C++ standard doesn't mandate any specific way of implementing
polymorphism. vtables are just the typical implementation.

2) Without knowing object type I can call methods of object using
those pointers.

As long as your pointer points at least to a base class.

So in which case RTTI is needed? ( Why I need to know my object
type?)

If you have a member function in a derived class that doesn't make sense for
the base or any other derived classes.

 

[Neo]

For example: safe downcasting of polimorphic types

dynamic_cast uses RTTI

Thanks to all for your inputs..