The XllPush library contains a set of classes that do all the hard work of implementation.
The two most important classes are CXllPushApp and CXllMtMsg. By implementing a child class descended from each of these base classes, you can avoid writing the bulk of the code required for an asynchronous add-in library.
This class is a child of CXllApp, and your application class should be descended from it, in place of CXllApp.
During the OnXllOpen() event, your implementation should call AddFunction(FunctionName) to register each of your asynchronous functions.
Your class must implement the event handler ProcessAsyncMessage(), which is called whenever a message is received from the background thread. Your implementation should update its data cache, and call UpdateCells(Topic) to update each of the cells connected to the topic.
Each of your asynchronous add-in functions should call AddConnection(), to register the connection between the cell containing the function and the external data it references.
Apart from these tasks, the push framework classes do all rest of the work. For more details, see CXllPushApp in the class reference.
Data sent from background threads to the main thread should be packaged into a class descended from the empty class CXllMtMsg. These packets can then be posted to the main thread, by calling CXllPushApp::PostMessage().
For more details, see CXllMtMsg in the class reference.