Robert Ramey wrote:
c) good documentation - mostly done as far as I can tell. I would like to see the singleton library have a tutorial section showing examples in a more "chatty" style. I'm aware of the necessity of "formal" documentation - but it's only really useful after one grasps the functionality and necessity of the package in more intuitive terms.
Yes, a brief tutorial is needed (figuring from a question on the usage I received via email). I'm thinking about a text with some simple code snippets for "here's how to basically use it", "you might use multiple inheritance to make some existing class a singleton", and "you might use non-public inheritance to create a purely static interface".
The singleton package is not currently in boost. In fact, its not even on the review schedule. as I see it I have a couple of options:
a) don't do anything, just wait until boost has a threadsafe singleton. I see no progress being made here. Currently there is no singleton implemenation in the review queue.
Well, my implementation has been uploaded just a few weeks ago. Anyway we might as well just request formal review - and, as the crowdedness has lightened, it won't take that long, especially if you volunteer to manage that review ;-).
b) hack away with some ad hoc version. - built on lightweight_mutex. Problem here is that there are no tests, no documentation, and no promise to keep it maintained and no promise to not change the interface in the future. (I like the size/speed and header only aspect)
AFAICT, our "lightweight toolbox" is still insufficient to implement a thread-safe Singleton - I might be missing something, though. How would you initialize 'lightweight_mutex' when you can't know that ctors are run in static context (as within a shared library)? Maybe it's possible to make 'detail::atomic_count' an aggregate and provide a macro for initialization (just as pthread does for its synchronization primitives). Then it would be trivial to implement a 'lightweight_once' on top of it... Thanks for your comments. Regards, Tobias