C++ Boost ASIO simple periodic timer?

Question

I want a very simple periodic timer to call my code every 50ms. I could make a thread that sleeps for 50ms all the time (but that's a pain)... I could start looking into Linux API's for making timers (but it's not portable)...

I'd like to use boost.. I'm just not sure it's possible. Does boost provide this functionality?

Answer 1

A very simple, but fully functional example:

#include <iostream>
#include <boost/asio.hpp>

boost::asio::io_service io_service;
boost::posix_time::seconds interval(1);  // 1 second
boost::asio::deadline_timer timer(io_service, interval);

void tick(const boost::system::error_code& /*e*/) {

    std::cout << "tick" << std::endl;

    // Reschedule the timer for 1 second in the future:
    timer.expires_at(timer.expires_at() + interval);
    // Posts the timer event
    timer.async_wait(tick);
}

int main(void) {

    // Schedule the timer for the first time:
    timer.async_wait(tick);
    // Enter IO loop. The timer will fire for the first time 1 second from now:
    io_service.run();
    return 0;
}

Notice that it is very important to call expires_at() to set a new expiration time, otherwise the timer will fire immediately because it's current due time already expired.