Step 7: Retrieval of Action Mapped Data

Action mapping was designed with buffered data in mind and will most often be used in that manner. The only difference between retrieving data from an action-mapped device and a device with no mapping is where you get it. Without action mapping, you would look to the dwOfs member of the DIDEVICEOBJECTDATA structure to determine which device object reported a change. However, with action mapping, you look to the uAppData member. Data is found in the dwData member.