How To Create TimerHandler Using Boost Library - c++

Question

I'm working on a project using C++.
I want a TimerHandler to be called after a specified time, but at the same time I don't want to block the current thread or any code after io.run() in the following code:
#include <iostream>
#include <string>
#include <boost/format.hpp>
#include <boost/asio.hpp>
#include <boost/bind.hpp>
#include <boost/date_time/posix_time/posix_time.hpp>
class TimerTest
{
public:
static void PrintOutTimerHandler(const boost::system::error_code&, const std::string& message)
{
std::cout << "PrintOutTimerHandler called: " << ", message: " << message << std::endl;
}
void run()
{
boost::asio::io_service io;
boost::asio::deadline_timer dt(io, boost::posix_time::seconds(5));
std::cout << "Start:\t" << std::endl;
dt.async_wait(boost::bind(PrintOutTimerHandler, boost::asio::placeholders::error, std::string("here is the message")));
// Do some job here
for (int i = 0; i < 1000000; ++i)
++i, --i;
std::cout << "End:\t" << std::endl;
io.run();
std::cout << "When to reach here 1: " << std::endl;
}
};
int main()
{
TimerTest tt;
tt.run();
std::cout << "When to reach here 2: " << std::endl;
return 0;
}
/* Current output:
Start:
End:
PrintOutTimerHandler called: , message: here is the message
When to reach here 1:
When to reach here 2:
*/
/* Expected output:
Start:
End:
When to reach here 1:
When to reach here 2:
PrintOutTimerHandler called: , message: here is the message
*/
I think I made myself clear. My questions are:
If this can be solved without
introducing a new thread, like Flex
ActionScript, that's is the best, but
I guess not (I guess ActionScript is
using a hidden thread);
If we have to
introduce an extra thread to do the
job, would you mind writing down the
pseudo code for me?
Thanks.
Peter

Answer 1

Here is an example . Run the io_service in a separate thread
asio::io_service io_service;
asio::thread t(boost::bind(&asio::io_service::run, &io_service));
or run it in a thread group
boost::thread_group threads;
for (std::size_t i = 0; i < my_thread_count; ++i)
threads.create_thread(boost::bind(&asio::io_service::run, &io_service));
Remember that your main thread should always run because when it exists all threads spawned will also exit.
I hope this helps.

Answer 2

I misunderstood what OrcunC said, but actually he is correct. Here is the modified version for your reference:
#include <iostream>
#include <string>
#include <boost/format.hpp>
#include <boost/asio.hpp>
#include <boost/bind.hpp>
#include <boost/thread.hpp>
#include <boost/date_time/posix_time/posix_time.hpp>
class TimerTest
{
public:
static void PrintOutTimerHandler(const boost::system::error_code&, const std::string& message)
{
std::cout << "PrintOutTimerHandler called: " << ", message: " << message << std::endl;
}
TimerTest(unsigned int timeout)
: dt(io, boost::posix_time::milliseconds(timeout))
{
}
void run()
{
std::cout << "Start:\t" << std::endl;
dt.async_wait(boost::bind(PrintOutTimerHandler, boost::asio::placeholders::error, std::string("here is the message")));
boost::thread thrd(boost::bind(&boost::asio::io_service::run, &io));
// Do some job here
for (int i = 0; i < 1000000; ++i)
++i, --i;
std::cout << "End:\t" << std::endl;
std::cout << "When to reach here 1: " << std::endl;
}
boost::asio::io_service io;
boost::asio::deadline_timer dt;
};
int main()
{
TimerTest tt(5000);
tt.run();
std::cout << "When to reach here 2: " << std::endl;
// Keep the main thread active for testing purpose. Otherwise,
// once the TimerTest object is destroyed when exiting the main() function,
// the sub thread spawed in tt.run() will also exit;
Sleep(10000);
}
/* Current output and Expected output:
Start:
End:
When to reach here 1:
When to reach here 2:
PrintOutTimerHandler called: , message: here is the message
*/