Property :: instanceArea - Provide instance area

The function provides the instance area for a selected property instance. When no instance is selected for a single reference, the function provides an initialized area. When no instance is selected in the upper property handle or when no instance is selected in a collection handle the function throws an exception.

When a selected instance could be provided in the property handle, the function checks, whether the type of the selected instance fits to the type name passed in sTypeName. When the instance does not inherit from the type passed, the function throws an exception, too.

The function can be called from C++ functions, only. It is mainly used by the operator -> in the SET template class.