マルチスレッドの使用例

multi_thread_worker.cpp

#include <iostream>
#include <memory>
#include <mutex>
#include <random>
#include <thread>
#include <vector>

static std::mutex mux;
std::random_device seed_gen;
std::default_random_engine engine(seed_gen());
std::uniform_int_distribution<> dist(1, 10);

static void locked_cout(const std::string& message)
{
  std::lock_guard<std::mutex> lock{mux};
  std::cout << message << std::endl;
}

class Worker
{
public:
  Worker(int num) : num_{num}
  {
  }

  void work()
  {
    auto sleep = dist(engine);
    locked_cout("Worker [" + std::to_string(this->num_) + "] start .. sleep " +
                std::to_string(sleep) + " seconds");
    std::this_thread::sleep_for(std::chrono::seconds(sleep));
    locked_cout("Worker end: " + std::to_string(this->num_));
  }

private:
  int num_;
};

int main()
{
  std::vector<std::shared_ptr<Worker>> container;
  std::vector<std::thread::thread> pool;

  for (int i = 0; i < 10; i++)
  {
    auto ptr = std::make_shared<Worker>(i);
    container.emplace_back(ptr);
    pool.emplace_back(std::bind(&Worker::work, ptr));
  }

  for (auto& th : pool)
  {
    th.join();
  }

  return 0;
}