How to Implement UMDF Callback Objects

A UMDF driver consists predominantly of a group of COM callback objects that respond to notifications by the UMDF runtime and allow the driver to handle events such as read or write requests. All callback objects are in-process COM objects. The basic requirements for implementing callback objects are relatively simple:

  • Implement the IUnknown methods to handle reference counting and provide pointers to the object’s interfaces.

  • Implement the UMDF callback interfaces that the object exposes.

This section discusses the basics of how to implement callback objects for UMDF drivers.

How to Implement a Class for a COM Object

Interfaces are not implemented in isolation; they must be exposed by an object. A typical approach ...

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