如何连接信号张贴在不同的线程工作时来提高:: ASIO :: io_service对象？

问题描述

我试图用一个boost :: lockfree队列管理任务。这些任务检索数据，并会在一个工作线程处理。一旦数据被检索，信号应被发送到与数据的主线。工作线程在应用程序开始启动，并只是不断轮询队列。我是新来的boost ::短耳但是从我的研究，这似乎是线程之间发送信号的最佳机制。

I'm trying to use a boost::lockfree queue to manage tasks. These tasks retrieve data and would be processed on a worker thread. Once data is retrieved, a signal should be sent to the main thread with the data. The worker thread is spawned at the start of the application and just keeps polling the queue. I'm new to Boost::Asio but from my research, it seems to be the best mechanism for sending signals between threads.

我已经看了几个例子，尤其是：

I've looked at several examples, in particular:

之后

• Confused when boost::asio::io_service run method blocks/unblocks
• boost asio post not working , io_service::run exits right after post

下面是我的code：

#include "stdafx.h"
#include <thread>

#include <boost/asio.hpp>
#include <boost/bind.hpp>
#include <boost/lockfree/spsc_queue.hpp>
#include <boost/optional.hpp>
#include <boost/thread.hpp>
#include <boost/signals2.hpp>

typedef boost::signals2::signal<void(int)> signal_type;

class Task
{
public:
    Task(int handle) : _handle(handle) {};
   ~Task() {};

   virtual void Execute()
   {
      int result = _handle * 2;
   }

private:
   int _handle;
};


class Manager
{
public:
   Manager() 
   {
      _mainService = std::make_shared<boost::asio::io_service>();
      _workerService = std::make_shared<boost::asio::io_service>();
      _work = std::make_shared<boost::asio::io_service::work>(*_workerService);

      _threadStarted = false;
      Start();
   };

   ~Manager() {};

   void WorkerMain()
   {
      _workerService->poll();
   }

   void Start()
   {
      if (_threadStarted) return;

      _workerThread = std::thread(&Manager::WorkerMain, this);
      _threadStarted = true;
   }

   void Stop()
   {
      if (_threadStarted == false) return;

      _mainService->stop();
      _workerThread.join();
      _mainService.reset();
   }

   void OnSignalFetchCompleted(int value)
   {
      int asdf = 0; //do stuff with data on main thread
   }

   void ProcessData(signal_type& signal)
   {
      int i = 0;

      do
      {
         _queue.consume_one([&](std::shared_ptr<Task> task)
         {
            task->Execute();
            //get data from task; send out signal with data
         });

         i++;
      } while (i < 3);
   }

   void QueueData(int handle)
   {
      _signalFetchCompleted.connect(boost::bind(&Manager::OnSignalFetchCompleted, this, _1));
      _workerService->post(boost::bind(&Manager::ProcessData, boost::ref(_signalFetchCompleted))); //!!does not compile

      std::shared_ptr<Task> task = std::make_shared<Task>(handle);
      _queue.push(task);
   }

private:
   boost::lockfree::spsc_queue<std::shared_ptr<Task>, boost::lockfree::capacity<1024>> _queue;
   std::thread _workerThread;
   bool _threadStarted;

   std::shared_ptr<boost::asio::io_service> _mainService;
   std::shared_ptr<boost::asio::io_service> _workerService;
   std::shared_ptr<boost::asio::io_service::work> _work;

   signal_type _signalFetchCompleted;
};


int _tmain(int argc, _TCHAR* argv[])
{
   std::shared_ptr<Manager> mgr = std::make_shared<Manager>();
   mgr->QueueData(5);
   mgr->QueueData(10);

   mgr->Stop();

   return 0;
}

我得到的_workerService->行后，我一直没能解决一个编译错误：

I'm getting a compile error on the _workerService->Post line that I haven't been able to resolve:

1>C:\Boost\boost/bind/mem_fn.hpp(333): error C2784: 'T *boost::get_pointer(const boost::scoped_ptr<T> &)' : could not deduce template argument for 'const boost::scoped_ptr<T> &' from 'const signal_type'
1>          C:\Boost\boost/smart_ptr/scoped_ptr.hpp(150) : see declaration of 'boost::get_pointer'
1>          C:\Boost\boost/bind/mem_fn.hpp(352) : see reference to function template instantiation 'R (__cdecl &boost::_mfi::dm<R,Manager>::call<const U>(U &,const void *) const)' being compiled
1>          with
1>          [
1>              R=void (signal_type &)
1>  ,            U=signal_type
1>          ]
1>          C:\Boost\boost/bind/mem_fn.hpp(352) : see reference to function template instantiation 'R (__cdecl &boost::_mfi::dm<R,Manager>::call<const U>(U &,const void *) const)' being compiled
1>          with
1>          [
1>              R=void (signal_type &)
1>  ,            U=signal_type
1>          ]
1>          C:\Boost\boost/bind/bind.hpp(243) : see reference to function template instantiation 'R (__cdecl &boost::_mfi::dm<R,Manager>::operator ()<T>(const U &) const)' being compiled
1>          with
1>          [
1>              R=void (signal_type &)
1>  ,            T=signal_type
1>  ,            U=signal_type
1>          ]

任何解决这种方法的这个编译错误或一般性意见帮助将不胜AP preciated。谢谢你。

Any help resolving this compile error or general comments on this approach would be greatly appreciated. Thanks.

推荐答案

在的新的信息，问题是你的的boost ::绑定。您正在试图调用一个成员函数没有一个对象来调用它：您要拨打过程数据，但你还没有告诉在哪个对象要调用bind它在。你需要给它一个管理​​来调用它：

In light of new information, the problem is with your boost::bind. You are trying to call a member function without an object to call it on: you are trying to call ProcessData but you haven't told the bind on which object you wish to call it on. You need to give it a Manager to call it on:

_workerService-＆GT;后期（的boost ::绑定（安培;管理::过程数据，对此，提振:: REF（_signalFetchCompleted）））;

这将调用过程数据在这个并传递到 _signalFetchCompleted

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