Porting to the Symbian Platform: Open Mobile Development in C/C++

Chapter 11. Porting Middleware

I have always wished for my computer to be as easy to use as my telephone; my wish has come true because I can no longer figure out how to use my telephone.

—Bjarne Stroustrup

This chapter is about porting middleware to the Symbian platform. We examine the subject via two case studies for middleware that is in the process of being ported. The first of these is an excellent example of platform-independent middleware, the open source Geospatial Data Abstraction Library (GDAL).^[184] As it deals with converting and manipulating various data formats, it has very few dependencies on system services. The second example, the Qt application framework, shows how highly platform-dependent middleware can also be portable. In this case, the libraries necessarily interact with a wide range of system services in order to provide a platform-independent interface for applications.

So, what exactly is middleware? It's a term used to refer to components that sit 'in the middle' between applications and lower-level APIs, such as those provided by the operating system, or third-party libraries. Originally used in distributed computing environments to abstract away network interface details, it now has much wider use, including application programming frameworks, game engines and multimedia libraries. A defining characteristic of middleware is that it doesn't do anything on its own, instead it provides services to an application or server, as well as a higher level of abstraction ...