Also, if people should look at intel's tbb(https://www.threadingbuildingblocks.org/intel-tbb-tutorial) library, it has been really excellent in my experience using at a respectably large scale.

edit: formatting

TBB is a little underwhelming in my opinion. Stuff like mutexes, condition variables and even atomics is pretty much standard nowadays (even if you need portability, you can usually rely on stuff like glib or Qt or boost); thread-safe collections are rarely the right solution, because too many fine-grained locks incur excessive overhead. The work-stealing queue is nice, but if you really want things to scale you need stuff like highly-parallel fast paths, with message passing on the slow paths. And this is where TBB falls a bit short of the expectations.

I wonder what do you find so simplifying in futures and promises? I use them heavily in one of the projects and compared to old-school mutexes and condition variables they seem to be just at the same abstraction level. They can cause very similar problems like deadlocks or race conditions, with the additional "bonus" of callback hell if you don't use any higher-level libraries.

I just wish GCD was ported everywhere and not just FreeBSD. It's much easier to work and think in terms of queues and groups than threads