Hi Frank,


>                Could you tell me something more about the following
> callback functions of the service tracker customizer:
>

Might I suggest you first take a look at the javadoc [1] and osgi
specification [2] if such questions rise? Celix follows this spec as close
as possible, and if something seems to be incorrect/unclear or missing, feel
free to ask.


>
>
> o   void *addingService(void *handle, ...)
>
> o   void addedService(...)
>
> What is the difference between addingService and addedService? What data
> should the function addingService return?
>

In this case, addingService is explained in the javadoc/spec. The
addedService method is an addition made and needed by the Felix
DependencyManger. For Celix we have chosen to add this function to the
default ServiceTracker.

The addedService function is a callback that can be used to be informed if a
service has actually been added to the tracker, whereas the addingService is
a hook used during the adding. It can be used to intercept the service and
eg perform additional filtering.
For Celix the adding, modified and removed follow the default OSGi tracker.

[1]: http://www.osgi.org/javadoc/r4v43/
[2]: http://www.osgi.org/Specifications/HomePage


-- 
Met vriendelijke groet,

Alexander Broekhuis