I started experimenting with Raspberry Pi GPIO using Python [1,2]. Then the original Gertboard kit was released so I ordered and built one which enabled me to play with BCM2835 peripheral IO beyond basic GPIO. At the time the Gertboard had test and example C code available  that, as with the Python case, I felt could be expressed more cleanly. I thought it would be interesting to see what advantages C++, hopefully C++11, features and idioms might provide.
I have posted some example code on GitHub showing the Shared Immutable, Exclusive Setup ideas discussed in the Comments on comments to Herb Sutter's updated GotW #6b solution (part 2) blog post to demonstrate the ideas:
Previously I wondered, from musing when reading Herb Sutter’s updated Guru of the Week 6b article, how one might – in C++11 – enforce a concurrent usage pattern in which an object can only be modified after creation by the creating thread until all modifications are done when the object becomes immutable and concurrently accessible. Concurrent access before an object becomes immutable is considered an error as are attempts to modify an object that is immutable.