The function is really simple once you have the parameters for the API figured out. The name of the device is the only parameter passed into the function. The function then calls the QDCRDEVD and returns the IP address from the data received. I have added some really simple error handling so that the IP address will be "ERROR" if the QDCRDEVD API does not execute properly.
As I mentioned, this same process can be used to determine the IP address of virtually any network device. The function could be modified easily to return IP addresses for other devices. I only needed the workstation devices so I didn't bother with the rest.
There are a few limitations to the QDCRDEVD API that you should be aware of before using it. The first one is that the device name must use all uppercase letters (QPADEV0001, not qapdev0001). If you have lowercase letters, it will return an error. Also, the API will not work at all with a device connected via pass-through (STRPASTHR), and it will not work for PC jobs that are calling RPG and/or CL commands.
There is a plethora of other information available about the device(s) in the datastream returned from QDCRDEVD. If you are interested, go to the IBM Information Center and search for QDCRDEVD.