LinuxCon Europe + CloudOpen Europe

The C and C++ standards define what constitutes a well-formed program. However, they steer clear of any issues related to ABI, binary compatibility and even modern dynamic loading of libraries. Yet developers for libraries are often faced with understanding and dealing with those issues that are out-of-scope for the standards. Far from an impossible task, there are simple guidelines, checklists, tooling, and processes that can be relied upon to guarantee binary compatibility between releases. Using them, it is possible to maintain large libraries compatible with previous versions for a long time, across multiple releases. This presentation will talk about those real-world problems and their solutions, heavily drawing upon the solutions used by both Qt and KDE. It will mostly focus on issues facing libraries on Linux, but will give hints also for cross-platform portability.