开发具有"futures"或类似范例C++并发库

Developing C++ concurrency library with "futures" or similar paradigm

Boost实现了futures和其他线程工具。

请注意，当您在boost::unique_future上调用get()方法时，它将重新抛出异步执行期间可能存储在其中的任何异常。

我建议你做一些类似的事情：

#pragma once
#include <tbb/concurrent_queue.h>
#include <boost/thread.hpp>
#include <boost/noncopyable.hpp>
#include <functional>
namespace internal
{
    template<typename T>
    struct move_on_copy
    {
        move_on_copy(const move_on_copy<T>& other) : value(std::move(other.value)){}
        move_on_copy(T&& value) : value(std::move(value)){}
        mutable T value;
    };
    template<typename T>
    move_on_copy<T> make_move_on_copy(T&& value)
    {
        return move_on_copy<T>(std::move(value));
    }
}
class executor : boost::noncopyable
{
    boost::thread thread_;
    tbb::concurrent_bounded_queue<std::function<void()>> execution_queue_;
    template<typename Func>
    auto create_task(Func&& func) -> boost::packaged_task<decltype(func())> // noexcept
    {   
        typedef boost::packaged_task<decltype(func())> task_type;
        auto task = task_type(std::forward<Func>(func));            
        task.set_wait_callback(std::function<void(task_type&)>([=](task_type& my_task) // The std::function wrapper is required in order to add ::result_type to functor class.
        {
            try
            {
                if(boost::this_thread::get_id() == thread_.get_id())  // Avoids potential deadlock.
                    my_task();
            }
            catch(boost::task_already_started&){}
        }));
        return std::move(task);
    }
public:
    explicit executor() // noexcept
    {
        thread_ = boost::thread([this]{run();});
    }
    ~executor() // noexcept
    {   
        execution_queue_.push(nullptr); // Wake the execution thread.
        thread_.join();
    }
    template<typename Func>
    auto begin_invoke(Func&& func) -> boost::unique_future<decltype(func())> // noexcept
    {   
        // Create a move on copy adaptor to avoid copying the functor into the queue, tbb::concurrent_queue does not support move semantics.
        auto task_adaptor = internal::make_move_on_copy(create_task(func));
        auto future = task_adaptor.value.get_future();
        execution_queue_.push([=]
        {
            try{task_adaptor.value();}
            catch(boost::task_already_started&){}
        });
        return std::move(future);       
    }
    template<typename Func>
    auto invoke(Func&& func) -> decltype(func()) // noexcept
    {
        if(boost::this_thread::get_id() == thread_.get_id())  // Avoids potential deadlock.
            return func();
        return begin_invoke(std::forward<Func>(func), prioriy).get();
    }
private:
    void run() // noexcept
    {
        while(true)
        {
            std::function<void()> func;
            execution_queue_.pop(func); 
                    if(!func)
                       break;
            func();
        }
    }   
};