What counts as a "valid complete object"?

[Og The Trog]

Hey everyone!

I was making my way through the documentation of the c++ language on this website and I was reading about type-casting, they were using the term "valid complete object" quite a bit, but I don't know what it means, so I was hoping you could tell me what exactly counts as a "valid complete object"

thanks.

[mutexe]

maybe this has to do with object slicing?

http://stackoverflow.com/questions/274626/what-is-the-slicing-problem-in-c

[andywestken]

A quick google later, I see this phrae is turning up in discussions about dynamic_cast.
e.g, from: C++ Type Casting
http://vernavi.com/tech/?page_id=156

dynamic_cast

Its purpose is to ensure that the result of the type conversion is a valid complete object of the requested class.

In this context, it saying that the result of a dynamic_cast (when used correctly, from a polymorphic base class to one of its derived classes) is guaranteed to be a complete and valid class.

If you misused static_cast, which doesn't make this guarantee, and the base class pointer/reference was referring to a class other than the one you cast the pointer/reference to, then the pointer/reference will end up referring to an object which very probably has the wrong size and layout.

Not sure I've been esp. clear, but that's the gist of it.

Andy