A simple thread pool based "parallel for" implementation for C++11.

cpp11_parallel_for.cpp

#include <atomic>
#include <thread>

template <typename COUNT_T, typename BODY_T>
void parallel_for(const COUNT_T count, BODY_T body) {
  std::vector<std::thread> workers;
  std::atomic<COUNT_T> next_job_id(0);
  for (unsigned int i = std::thread::hardware_concurrency(); i > 0; --i) {
    workers.emplace_back([&]() {
      while (true) {
        const auto job_id = next_job_id++;
        if (job_id >= count) {
          return;
        }
        body(job_id);
      }
    });
  }
  for (auto& worker : workers) {
    worker.join();
  }
}

// ...

void example(const std::vector<item_t>& items) {
  parallel_for(items.size(), [&](std::size_t k) {
    std::cout << "Processing item " << k << "\n";
    const auto& item = items[k];
    // ...
  });
}