I have a feeling Howard might be the person to discuss this matter, but I'll throw it out here for everyone. I'm sure it is a discussion that would draw interest from other mac developers.
I'm working on transitioning our codebase to C++11. The problem is that we still have to support 10.6 for another couple of years at least. I got this wild idea that perhaps I could deploy c++11 code to 10.6 by building the latest versions of clang & libc++ on 10.6. I got clang built. I got libc++ to build as a static lib. I got libc++abi to build as a dylib. I was able to build and run a test program with c++11 STL code on 10.6. Test successful.
HOwever, I have a few questions before I invest any more energy in this:
1) If I start using the frameworks and libs in the 10.6 SDK to build full-blown mac applications, am I going to have problems with mixing two std library implementations in a single process?
2) I'm using the latest code for all the projects. Is this software stack reliable and production-quality on 10.6? I don't have the expectation that Apple would support using the tools on 10.6, but I'm just asking in terms of what you know about the innards of the technologies involved.
3) Am I going to have any limitations on the C++11 functionality on 10.6? For instance, based on previous conversations on this list, I don't expect 'thread_local' to ever work on 10.6. Are there any other such features that have no chance of working on 10.6?
4) Since we are a developer of commercial desktop apps, I prefer to use static libs to avoid giving the customers the ability to break the app. On OSX, a dylib wouldn't be a deal-breaker given I could load it in the app's bundle, but I'd still prefer the static libs if possible. I built libc++abi as a static lib, but I'm finding that I get number of duplicate symbol errors when I try to link both libc++.a and libc++abi.a with an executable program. Clearly, I have to merge the two libs. I have not attempted to do any analysis yet on the functions, but I suspect the libc++abi duplicated functions are going to be identical to what is in libc++. Is this true? Do you foresee any problems with deleting one set of the duplicate functions in one of the libraries?