Multithreading agnostic progress bar (RcppParallel, pthreads, openmp)

[traversc]

I wrote a short gist based on the idea in this package that should work for RcppParallel and any other multithreading framework. https://gist.github.com/traversc/8b26b9e689b23d3a174aee296c0503ca

I think this general approach would be nice to see in this package.

The changes you'd need to make are not too many. In summary:

• counter -> std::atomic
• increment -> counter.fetch_add(1)
• Check for main thread -> std::this_thread::get_id()

[kforner]

Hello, What are the practical advantages ?

[traversc]

The practical advantage is it should work using RcppParallel or C++ std::threads.