C++ Boost multithreading inside a class - c++

Question

I am following Boost multithreading tutorial here
. Following section 18.13, I try creating a class containing multiple threads as follows:
#define _CRT_SECURE_NO_WARNINGS
#include <ctime>
#include <iostream>
#include <string>
#include <queue>
#include <boost/array.hpp>
#include <boost/bind.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/asio.hpp>
#include <boost/lexical_cast.hpp>
#include <boost/thread.hpp>
#include <boost/thread/thread.hpp>
#include <boost/chrono.hpp>
#include <boost/date_time/posix_time/posix_time.hpp>
using boost::asio::ip::udp;
using std::cout;
using std::cin;
using std::endl;
using std::string;
using namespace std;
class MultiTask
{
private:
boost::thread_group threads; // thread group
boost::thread* thread_main; // main thread
boost::thread* thread_output; // output thread
boost::thread* thread_input; // input thread
boost::mutex stopMutex;
bool stop;
int i_in, i_out, i_main;
string userInput;
public:
// constructor
MultiTask()
{
thread_main = new boost::thread(boost::ref(*this));
thread_output = new boost::thread(&MultiTask::Callable_Out, this, 1000, boost::ref(i_out));
thread_input = new boost::thread(&MultiTask::Callable_In, this, 1000, boost::ref(i_out), boost::ref(userInput));
//threads.add_thread(thread_main); // main thread = 0 // will throw -> boost thread: trying to join itself
threads.add_thread(thread_output); // output thread = 1
threads.add_thread(thread_input); // input thread = 2
stop = false;
i_in = 0;
i_out = 0;
i_main = 0;
userInput = "";
}
// destructor
~MultiTask()
{
// stop all threads
Stop();
// show exit message
cout << "Exiting MultiTask." << endl;
}
// start the threads
void Start()
{
// Wait till they are finished
threads.join_all();
}
// stop the threads
void Stop()
{
// warning message
cout << "Stopping all threads." << endl;
// signal the threads to stop (thread-safe)
stopMutex.lock();
stop = true;
stopMutex.unlock();
// wait for the threads to finish
threads.interrupt_all();
threads.join_all();
}
void Callable_Out(int interval, int& count)
{
while (1)
{
//cout << "Callable_Out [" << count++ << "]" << endl;
boost::this_thread::sleep(boost::posix_time::millisec(interval));
boost::this_thread::interruption_point();
}
}
void Callable_In(int interval, int& count, string& userInput)
{
while (1)
{
cout << "Callable_In [" << count++ << "]. Enter message: ";
getline(cin, userInput);
boost::this_thread::sleep(boost::posix_time::millisec(interval));
boost::this_thread::interruption_point();
}
}
// Thread function
void operator () ()
{
while (1)
{
//cout << "Main [" << i_main++ << "]." << endl;
//cout << "Main [" << i_main++ << "]. " << userInput << endl;
if (userInput == "STOP")
{
try
{
this->Stop();
}
catch(exception e)
{
cout << e.what() << endl;
}
}
boost::this_thread::sleep(boost::posix_time::millisec(1000));
boost::this_thread::interruption_point();
}
}
};
int main()
{
MultiTask mt;
mt.Start();
}
However, VS throws two of these errors:
Severity Code Description Project File Line Suppression State
Error C2198 'void (__cdecl *)(boost::posix_time::millisec,int &,std::string &)': too few arguments for call mycpp c:\boost_1_66_0\boost\bind\bind.hpp 259
Can someone please help? This is from section 18.13. Also, I do not see where to input the arguments for CallableFunction() in that example. How can it be done in my case? Thanks.

Answer 1

In tutorial CallableFunction function takes only one parameter, it is passed as second parameter in thread constructor new boost::thread(&CallableFunction, i);.
In your case Callable_Out takes 2 parameters, one is missing, you should call
thread_output = new boost::thread(&Callable_Out, boost::posix_time::millisec(0), boost::ref(i_out));
and for Callable_In you call
thread_input = new boost::thread(&Callable_In, boost::posix_time::millisec(1), boost::ref(i_out), boost::ref(userInput));