Performs a shallow clone of this object. 

Returns a SmartPointer to the newly created clone, and adds a record to the specified ID map. 

If the cloning operation fails, a null SmartPointer is returned. 

A shallow clone is a clone of only this object. 

This function should not be called by client code; use OdDgDatabase::wblockCloneObjects() instead. 

The default implementation of this function calls subWblockClone() for all objects hard-referenced by this object. This function can be overridden in custom classes.

subDeepClone()