I have some questions:
* Why the submit function of all the thread pools doesn't returns the same? * What is the advantage of returning future from submit call? ....
My personal big issue with a Boost.Thread threadpool is why adding one is necessary when forty lines of C++11 code using Boost.ASIO implements you one: /*! \class thread_pool \brief A very simple thread pool based on Boost.ASIO and std::thread */ class thread_pool { class worker { thread_pool *pool; public: explicit worker(thread_pool *p) : pool(p) { } void operator()() { pool->service.run(); } }; friend class worker; std::vector< std::unique_ptr<thread> > workers; boost::asio::io_service service; boost::asio::io_service::work working; public: //! Constructs a thread pool of \em no workers explicit thread_pool(size_t no) : working(service) { workers.reserve(no); for(size_t n=0; n<no; n++) workers.push_back(std::unique_ptr<thread>(new thread(worker(this)))); } ~thread_pool() { service.stop(); for(auto &i : workers) i->join(); } //! Returns the underlying io_service boost::asio::io_service &io_service() { return service; } //! Sends some callable entity to the thread pool for execution template<class F> future<typename std::result_of<F()>::type> enqueue(F f) { typedef typename std::result_of<F()>::type R; // Somewhat annoyingly, io_service.post() needs its parameter to be copy constructible, // and packaged_task is only move constructible, so ... auto task=std::make_shared<boost::packaged_task<R>>(std::move(f)); // NOTE to self later: this ought to go to std::packaged_task<R()> service.post(std::bind([](std::shared_ptr<boost::packaged_task<R>> t) { (*t)(); }, task)); return task->get_future(); } }; ... and you're done. Moreover, this thread pool integrates seamlessly with Boost.ASIO ioservice callback dispatch which is a huge plus. I took that example from some page on the internet, so I don't claim I wrote most of the above. Do bear in mind before you respond that parts of Boost.ASIO are scheduled to enter the standard in TR2, therefore no you won't need Boost.ASIO as a dependency soon. I'm not ruling out the merit of a Boost.Thread threadpool. For me personally though, the hurdle is very significantly raised: you need to strongly prove to me why your proposed thread pool is much superior to a Boost.ASIO based threadpool. Otherwise I will zero score the GSoC proposal, because in the end we need other proposed projects more. By the way, I actually don't object at all if your proposed Boost.Thread threadpool is a thin wrapper of Boost.ASIO. That, actually, is just fine with me, though I'd doubt Google would feel it substantial enough for GSoC funding seeing as it would be finished within a week. Niall