>>>>> "Hyrum K. Wright" <hyrum_wri...@mail.utexas.edu>:
> At this point, it's my turn to get confused. I'm speaking > specifically of cases where we return STL classes. Brane's earlier > suggestion to create an implicit bool conversion works fine for our > custom classes. The problem I'm trying to solve is "how does one > return the equivalent of '(const char *) NULL' in an std::string?" > It's a this point that pointers start coming into play, because a NULL > std::string * is quite feasible, whereas a NULL std::string isn't. Ah, ok. That was at a different part of the thread... which I avoided responding to because I have any good answers at hand. :-) Do you need the distrinction between an empty string and a NULL? If not then I would return an empty string for a NULL on the C side. There's also the consideration that some std::string implementations are deep copying (the gcc version uses refcounting (or at least used to do so), but the VC++ one used to use deep copying. I'm not sure if that still is the case). Then maybe what you want to return is const std::string& (which leaves you with the headache of managing the life cycle of the std::string, so maybe not... though... you have the context of the wrapper class and could cache them lazily there. That would increase the footprint of the wrapper, though).
