ObjectPtrT question

Hi,

I'm writing a custom appender for log4cxx, and have a few questions about the 
Object/ObjectImpl/ObjectPtrT classes.....Basically I'm going to code a number 
of classes that extend ObjectImpl, to make use of the ObjectPtrT "smart 
pointer" template and the Java-inspired threading methods, wait, notifiy, 
notifyAll (and I notice you have a semaphore imp...nice). 

My question is a very general one.....what are the general rules of thumb 
you've been using when extending the ObjectImpl class?.... I've noticed the 
object macros (eg. casting ones), and will be including them in the 
declarations and implementations for my descendant classes. Can't say I'm 
entirely sure of the purpose of the cast method defined by the object class and 
implemented by the macros....is this just supposed to be a safe way of 
dynamically down-casting an object?....if so why was this method chosen in 
favour of the builtin dynamic_cast mechanism?...anyway, my C++ is good, but not 
exceptional (yet :-) ), so please excuse me if I've missed something here.

Any help/advice would be very appreciated.

Thanks in advance,
Jess Morecroft 

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