Maintaining Binary Compatability

It seems to be common practice for software development companies to patch individual parts of a released product. Usually this means distributing a second installer that creates new shared object (.so or .dll) files, so the next time the application in question runs it loads the new object files, and thus runs the new code.

In practice this is a great idea - it means that companies don't need to re-release and re-ship the entire product. Unfortunately, it's not always that easy. The biggest problem is that the new libraries must be binary compatible with the old ones. Essentially this means making sure that all objects within the library are the same size as they were, and that things like vtables haven't changed.

For a while now I've been looking around for a definitive list of guidelines to help me maintain binary compatible libraries. I finally found it on the KDE website.

Behold: Binary Compatible Issues with C++

Anyway, I thought that might be useful to some of you. Enjoy!