ofPtr casting

hey!
is there a sensible mechanism for casting ofPtr e.g.

  
  
ofPtr<Derived> myThingy;  
ofPtr<BaseClass> myAbstractThingy;  
myAbstractThingy = myThingy  
  

Currently being led to
http://msdn.microsoft.com/en-us/library/bb982457(v=vs.90).aspx

aha
that actually works!
i was trying a different syntax before
i.e. implicit casting
which doesn’t work
but explicitly casting like this does work
so can do

  
  
myFunctionThatTakesBase( ofPtr<BaseClass>(myThingy ) ); //ok  
myFunctionThatTakesBase(myThingy); //not ok