Re: [orbitcpp-list] More questions...

[Phil D. <ph...@us...>]

Hi Mike,

Mike Bond writes:
 > I was noticing in some of your test code that after calling
 > orb->string_to_object() you call obj->_narrow(). If my understanding
 > is correct, this is essentially a cast mechanism.
 > 

Yep,

 > My first question is why is this done in orbitcpp but not in ORBit, is
 > it simply because C++ handles casting differently or is there more to it?

Nothing fancy - it's just a difference in the specs. C object refs are
typedef'd void ptrs anyway, so you can use them interchangably without
the compiler complaining. C++ object refs are statically typechecked
by the compiler, and so you need a safe way to do the casts.

 > Also, the implementation of _narrow() appears to be calling _duplicate(),
 > is it truly allocating a new object and copying as the name suggests, or
 > just doing some refcounting?
 > 

The duplicate() semantically copies the object *reference*, not the
object itself (and CORBA::Object::release() releases the object ref,
but doesn't delete the object). Under the hood, reference counting is
done by the Orbit C core.


 > Also, does one need to call CORBA::release() separately for both the
 > reference returned by string_to_object() as well as the reference
 > returned by _narrow()?
 > 

Yep, because they are 2 seperate refs. (However, if you use _vars,
this is done automatically when the ref goes out of scope)

Hope this helps,

Phil.