Cross platform C++ code architecture

Question

I'm having a bit of a go at developing a platform abstraction library for an application I'm writing, and struggling to come up with a neat way of separating my platform independent code from the platform specific code.

As I see it there are two basic approaches possible: platform independent classes with platform specific delegates, or platform independent classes with platform specific derived classes. Are there any inherent advantages/disadvantages to either approach? And in either case, what's the best mechanism to set up the delegation/inheritance relationship such that the process is transparent to a user of the platform independent classes?

I'd be grateful for any suggestions as to a neat architecture to employ, or even just some examples of what people have done in the past and the pros/cons of the given approach.

EDIT: in response to those suggesting Qt and similar, yes I'm purposely looking to "reinvent the wheel" as I'm not just concerned with developing the app, I'm also interested in the intellectual challenge of rolling my own platform abstraction library. Thanks for the suggestion though!

Answer 1

You might also want to take a look at poco:

The POCO C++ Libraries (POCO stands for POrtable COmponents) are open source C++ class libraries that simplify and accelerate the development of network-centric, portable applications in C++. The libraries integrate perfectly with the C++ Standard Library and fill many of the functional gaps left open by it. Their modular and efficient design and implementation makes the POCO C++ Libraries extremely well suited for embedded development, an area where the C++ programming language is becoming increasingly popular, due to its suitability for both low-level (device I/O, interrupt handlers, etc.) and high-level object-oriented development. Of course, the POCO C++ Libraries are also ready for enterprise-level challenges.

poco architecture http://pocoproject.org/images/poco.png

Answer 2

Have a look at ACE. It has a pretty good abstraction using templates and inheritance.