boost::asio序列: boost::bind 和 std::bind 和 class member function

1. boost::bind => class member function

#include <iostream>
#include <boost/asio.hpp>
#include <boost/bind.hpp>
#include <boost/date_time/posix_time/posix_time.hpp>

class printer
{
public:
  printer(boost::asio::io_context& io)
    : timer_(io, boost::posix_time::seconds(1)),
      count_(0)
  {
    timer_.async_wait(boost::bind(&printer::print, this));
  }

  ~printer()
  {
    std::cout << "Final count is " << count_ << std::endl;
  }

  void print()
  {
    if (count_ < 5)
    {
      std::cout << count_ << std::endl;
      ++count_;
      // 从新开始计时器新的计时
      timer_.expires_at(timer_.expires_at() + boost::posix_time::seconds(1));
      timer_.async_wait(boost::bind(&printer::print, this));
    }
  }

private:
  boost::asio::deadline_timer timer_;
  int count_;
};

int main()
{
  boost::asio::io_context io;
  printer p(io);
  io.run();

  return 0;
}

2. std::bind => class member function

#include <iostream>
#include <boost/asio.hpp>
#include <boost/bind.hpp>
#include <boost/date_time/posix_time/posix_time.hpp>

class printer
{
public:
  printer(boost::asio::io_context& io)
    : timer_(io, boost::posix_time::seconds(1)),
      count_(0)
  {
    timer_.async_wait(boost::bind(&printer::print, this));
  }

  ~printer()
  {
    std::cout << "Final count is " << count_ << std::endl;
  }

  void print()
  {
    if (count_ < 5)
    {
      std::cout << count_ << std::endl;
      ++count_;

      timer_.expires_at(timer_.expires_at() + boost::posix_time::seconds(1));
      timer_.async_wait(boost::bind(&printer::print, this));
    }
  }

private:
  boost::asio::deadline_timer timer_;
  int count_;
};

int main()
{
  boost::asio::io_context io;
  printer p(io); // 第一次投递超时事件
  io.run();

  return 0;
}

前一篇博客bind的函数为全局函数，这一篇版本的函数为类的成员函数，实际上都是类似的，这里只是做出一个比较，你可以采用自己喜欢的风格即可