boost：：asio：:d eadline_timer 不调用处理程序

我想你一定是把io_service的多个实例搞混了。

我认为这是因为在你的代码中你从来没有显示你如何初始化timeout_。和io_service实例你正在使用的连接只实例化你的tcpPoll函数内…这让我相信你不小心在一个单独的io_service上注册了截止日期计时器，你甚至没有运行?

这里是一个实际工作的版本，注意:

1. 已经取消了stopped_布尔值，因为它是不必要的，并且必然会混淆
2. 查看check_timeout和stop关于如何检测各种程序流的新实现
3. 完整的代码，独立的，仅仅比你在
问题中发布的代码多几行。

#include <iostream>
#include <boost/asio.hpp>
#include <boost/bind.hpp>
using tcp = boost::asio::ip::tcp;
struct NetworkEntity {
    boost::asio::io_service io_service;
    boost::asio::deadline_timer timeout_{io_service};
    std::string address_ = "localhost";
    std::string port_    = "6767";
    int TIMEOUT_         = 3;
    boost::shared_ptr<tcp::socket> socket_;
    boost::asio::streambuf request_, answer_;
    void stop()
    {
        if (socket_)
        {
            socket_->cancel();
            socket_->close();
        }
        timeout_.cancel();
        io_service.stop();
    }
    void check_timeout(const boost::system::error_code& error)
    {
        if (error != boost::asio::error::operation_aborted)
        {
            stop();
            std::cout << address_ << " timed outn";
        }
        timeout_.async_wait(boost::bind(&NetworkEntity::check_timeout, this, boost::asio::placeholders::error));
    }
    std::vector<std::string> tcpPoll(const char* message, const char endOfMessage)
    {
        timeout_.expires_from_now(boost::posix_time::seconds(TIMEOUT_));
        timeout_.async_wait(boost::bind(&NetworkEntity::check_timeout, this, boost::asio::placeholders::error));
        tcp::resolver resolver(io_service);
        start_connect(&io_service, resolver.resolve(tcp::resolver::query(address_, port_)), message, endOfMessage);
        io_service.run();
        //retrieve answer from class
        //return answer
        std::ostringstream oss;
        oss << &answer_;
        return { oss.str() };
    }
    void start_connect(boost::asio::io_service* io_service, tcp::resolver::iterator endpoint_iterator, const std::string message, const char endOfMessage)
    {
        socket_.reset(new tcp::socket(*io_service));
        socket_->async_connect(endpoint_iterator->endpoint(),
                boost::bind(&NetworkEntity::handle_connect, this, io_service, boost::asio::placeholders::error, endpoint_iterator, message, endOfMessage));
    }
    void handle_connect(boost::asio::io_service* io_service,
            const boost::system::error_code& err,
            tcp::resolver::iterator endpoint_iterator,
            const std::string message,
            const char endOfMessage)
    {
        if (err)
        {
            std::cout << "Connect error: " << err.message() << "n";
            stop();
        }
        else
        {
            start_write(message, endOfMessage);
        }
    }
    void start_write(const std::string message, const char endOfMessage)
    {
        std::ostream request_stream(&request_);
        request_stream << message;
        boost::asio::async_write(*socket_, request_,
                boost::bind(&NetworkEntity::handle_write, this, boost::asio::placeholders::error, endOfMessage));
    }
    void handle_write(const boost::system::error_code& error, const char endOfMessage)
    {
        if (!error)
        {
            //sleep for 500ms to let time for the reciever to process info (had a bug on this one)
            start_read(endOfMessage);
        }
        else
        {
            std::cout << "write error : " << error.message() << "n";
            stop();
        }
    }
    void start_read(const char endOfMessage)
    {
        boost::asio::async_read_until(*socket_, answer_, endOfMessage,
                boost::bind(&NetworkEntity::handle_read, this, boost::asio::placeholders::error));
    }
    void handle_read(const boost::system::error_code& error)
    {
        if (error)
        {
            std::cout << "read error : " << error.message() << "n";
        }
        stop();
    }
};
int main()
{
    NetworkEntity ne;
    for (auto& s : ne.tcpPoll("this is my request", 'n'))
    {
        std::cout << "Line: '" << s << "'n";
    }
}