Note that this would also solved problem in enable_current_exception with virtual base classes that are not default constructible - mentioned in earlier thread.
It would, but I don't see a reason to use exception types without default constructors with Boost Exception. So, in my mind this problem is only theoretical.
What about integrating with existing exception hierarchies? (I know the example I gave previously of my project is not such hierarchy... :)). But on the other hand existing hierarchies likely do not use virtual inheritance as you have already mentioned somewhere before if I am not mistaken. Still there are reasons. In cases someone wants extra care he/she cannot use Boost.Exception data injection because this always adds risk of double failure - lack of memory and std::bad_alloc (or even something unpredictable as if I am not mistaken Standard puts low requirements on implementations on what, when and where can be thrown and only recommends standard exceptions) - which would mask the original failure. In case of my example of storing DWORD with GetLastError result in a modern PC machine chances of lack of memory are extremely low. However when talking about embedded systems or exceptions with more (maybe even lots) of data this becomes important. So to sum up IMHO if the implementation already uses this mechanism and all the required work is to make it public and document it then I would do it even if I didn't see practical use at the moment (I feel a bit mathematician and I do recall theories which also seemed useless at the moment of creation but then became important... :)). And in this case it seems (at least IMO) there are justified and possible if not likely use cases (the ones I mentioned earlier in the post). But you are not me and I do not feel entitled to modify Boost.Exception on my own so the final choice is yours. Since it seems I am the first and only one requesting this then maybe after all it is not important enough. (And yes. I know I can modify my own Boost to make this change and use it but I don't think it is a good idea especially that I am not the only person working on the project and we do constantly update Boost version instead of sticking to one particular.) Adam Badura