boost asio异步等待条件变量 [英] boost asio asynchronously waiting on a condition variable

问题描述

是否可以对boost :: asio中的条件变量执行异步等待（读取：非阻塞）？如果它不是直接支持任何提示实现它将不胜感激。

Is it possible to perform an asynchronous wait (read : non-blocking) on a conditional variable in boost::asio ? if it isn't directly supported any hints on implementing it would be appreciated.

我可以实现一个定时器和唤醒，甚至每几个毫秒，但这是方法是非常差，我发现很难相信条件变量同步没有实现/记录。

I could implement a timer and fire a wakeup even every few ms, but this is approach is vastly inferior, I find it hard to believe that condition variable synchronization is not implemented / documented.

推荐答案

如果我正确理解了意图，那么当一个条件变量被发出时， asio线程池？我认为在处理程序的开头等待条件变量就足够了， io_service :: post（）本身返回到池中，这是这样的：

If I understand the intent correctly, you want to launch an event handler, when some condition variable is signaled, in context of asio thread pool? I think it would be sufficient to wait on the condition variable in the beginning of the handler, and io_service::post() itself back in the pool in the end, something of this sort:

#include <iostream>
#include <boost/asio.hpp>
#include <boost/thread.hpp>
boost::asio::io_service io;
boost::mutex mx;
boost::condition_variable cv;
void handler()
{
    boost::unique_lock<boost::mutex> lk(mx);
         cv.wait(lk);
    std::cout << "handler awakened\n";
    io.post(handler);
}
void buzzer()
{
    for(;;)
    {
        boost::this_thread::sleep(boost::posix_time::seconds(1));
        boost::lock_guard<boost::mutex> lk(mx);
            cv.notify_all();
    }
}
int main()
{
    io.post(handler);
    boost::thread bt(buzzer);
    io.run();
}

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