SafeCallException handles exceptions in methods that use the safecall calling convention. Some classes that implement interfaces override this method to handle errors that might occur. TComponent calls the implementation of this method for the interface supported by the component, if it exists. If the component does not support interfaces, this method calls the SafeCallException method inherited from TObject, which returns E_UNEXPECTED. This is a default return value that is appropriate for classes that do not support any interfaces. 

System::TObject::SafeCallException