Yes, it's actually become stronger in Qt 4. Though I don't know quite what you mean with it making them harder to extend. Unless you were planning on doing on

Yes, it's actually become stronger in Qt 4. Though I don't know quite what you mean with it making them harder to extend. Unless you were planning on doing one of the "#define private public" hacks the "impl" would have been private anyway and not something that you could override. In 10 years of using Qt, I'm not sure I've ever thought to myself, "Damn, if only that wasn't in the data-pointer." There have been times when something was botched or broken or needed to be overridden when a mechanism wasn't there for such, but that didn't have anything to do with them using a pimpl pattern.