David,

>Unfortunately, as the Init method sometimes returns .F., I have been forced to used a parameter by reference to return the object. So you would have to do something like RETURN DODEFAULT(@oObject) instead, and I am not even sure that it would work. That is why I created the Initiate() method as a replacement of Init().
>I am going to look at getpem(). I suppose that it means that the check can be done only at runtime (but I expected that anyway).

You can put that in the class documentation so that developers creating subclasses can correctly write their code.

>I have given it a try without success. Do you have any idea about what search words to use ?

Try message #585856