Automation Types While IDispatch is not our favorite interface, we love the marshaler that Microsoft wrote for it. Usually called the type library marshaler because it performs marshaling based on the contents of a type library, this marshaler (contained in oleaut32.dll) can be used not only for IDispatch-based interfaces but also for custom interfaces that restrict themselves to Automation-comp..

Why type library marshaling? Type library marshaling is the most general type of marshaling. It’s a form of standard marshaling but doesn’t require that you supply your own proxy-stub components: instead, you use the IDispatch marshaler supplied by COM in oleaut32.dll. The IDispatch marshaler can be used by IDispatch, IDispatch-derivative interfaces, and even custom interfaces (derived from IUnk..