9

当我尝试获取（未设置！）使用 boost expires_from_now() 的当前到期时间似乎实际上取消了计时器，但它实际上按预期运行，但最终没有调用处理程序。

或者换句话说，当使用 expires_from_now() 访问 deadtime_timer 时，它将立即调用处理程序，而不是在处理程序到期时调用处理程序。

请考虑以下代码和相应的输出：

#include <boost/asio.hpp> 
#include <boost/thread.hpp> 
#include <boost/date_time/posix_time/posix_time.hpp>
#include <boost/date_time/posix_time/posix_time_io.hpp>
#include <iostream> 

using namespace boost::posix_time;
using namespace std;

void handler1(const boost::system::error_code &ec) 
{ 
    if (ec == boost::asio::error::operation_aborted)
    {
        std::cout << microsec_clock::local_time() << " Handler1: Timer 1 was cancelled or retriggered." << std::endl; 
    }
    else
    {
        std::cout << microsec_clock::local_time() << " Handler1: expired." << std::endl; 
    }
} 

boost::asio::io_service io_service1; 

class Mytimer {
public:
    Mytimer();
    void startTimer();
    void runTimerThread();
    bool isRunning();
private:
    bool m_isRunning;
    boost::asio::deadline_timer* m_pTimer;
    boost::thread* m_pThread;
};

Mytimer::Mytimer()
  : m_pTimer(NULL),
    m_pThread(NULL)
{
    m_pTimer = new boost::asio::deadline_timer(io_service1); 
    m_pTimer->async_wait(handler1); 
}

void Mytimer::runTimerThread()
{
    io_service1.run();
}

void Mytimer::startTimer()
{
    m_pThread = new boost::thread(&Mytimer::runTimerThread, this);
    m_pTimer->expires_from_now(boost::posix_time::seconds(10));
}

bool Mytimer::isRunning()
{

    time_duration td = m_pTimer->expires_from_now();
    if (td.total_seconds() > 0)
    {
        return true;
    }
    return false;
}

int main() 
{ 
    time_facet *facet = new time_facet("%Y%m%d %H:%M:%S%f");
    std::cout.imbue(std::locale(std::cout.getloc(), facet));

    cout << microsec_clock::local_time() << " before timer construction" << endl;
    Mytimer timer;
    cout << microsec_clock::local_time() << " before startTimer()" << endl;
    timer.startTimer();
    cout << microsec_clock::local_time() << " IsRunning: " << timer.isRunning() << endl;
    for (int i = 0; i <= 20; i++)
    {
        sleep(1);
        cout << microsec_clock::local_time() << " IsRunning: " << timer.isRunning() << endl;
    }
}

20120412 22:41:45689235 在计时器构造之前
20120412 22:41:45689514 在 startTimer() 之前
20120412 22:41:45689619 IsRunning: 1
20120412 22:41:45689693 Handler1：计时器 1 已取消或重新触发。
20120412 22：41：46689792 ISRUNGNUSN：1
20120412 22：41：47689994 ISRUNNNUMNNIUNN：1
20120412 22：41：48690179 ISRUNNUNNINNE：1
20120412 22：41：
41：41：49690375
ISRINN 51690712 ISRUNNNING：1
20120412 22：41：52690884 ISRUNNNUMN：1
20120412 22：41：53691069 ISRINNUNN：1
20120412 22：41：41：
41：
41：54691236 ISRUNNINN
20120412 22：41：57691810 Isrunning：0
20120412 22：41：58692001 ISRUNNNING：0
20120412 22：41：59692193 ISRUNNINNE：0
20120412 22：42：
42：00692364 ISRINNUMNING
ISRINNUMN 02692706 IsRunning: 0
20120412 22:42:03692886 IsRunning: 0
20120412 22:42:04693071 IsRunning: 0
20120412 22:42:05693267 IsRunning: 0
20120412 22:42:066934

4

2 回答 2

11

当我尝试获取（未设置！）使用 boost expires_from_now() 的当前到期时间似乎实际上取消了计时器，但它实际上按预期运行，但最终没有调用处理程序。

这个假设是不正确的。当你创建你的deadline_timer

m_pTimer = new boost::asio::deadline_timer(io_service1);
m_pTimer->async_wait(handler1);

你已经告诉它立即过期。然后，当你开始你的io_service

m_pThread = new boost::thread(&Mytimer::runTimerThread, this);

您随后调用

m_pTimer->expires_from_now(boost::posix_time::seconds(10));

正如文档中清楚描述的那样，这将取消任何未完成的处理程序，重点是我的

该函数设置到期时间。任何挂起的异步等待操作都将被取消。每个取消操作的处理程序将使用boost::asio::error::operation_aborted错误代码调用。

Mytimer::startTimer()要解决此问题，请按如下方式更改您的方法

--- timer4.cc.orig  2012-04-13 11:18:47.000000000 -0500
+++ timer4.cc   2012-04-13 11:16:54.000000000 -0500
@@ -1,4 +1,3 @@
-
 #include <boost/asio.hpp> 
 #include <boost/thread.hpp> 
 #include <boost/date_time/posix_time/posix_time.hpp>
@@ -39,7 +38,6 @@
     m_pThread(NULL)
 {
     m_pTimer = new boost::asio::deadline_timer(io_service1); 
-    m_pTimer->async_wait(handler1); 
 }

 void Mytimer::runTimerThread()
@@ -49,8 +47,9 @@

 void Mytimer::startTimer()
 {
-    m_pThread = new boost::thread(&Mytimer::runTimerThread, this);
     m_pTimer->expires_from_now(boost::posix_time::seconds(10));
+    m_pTimer->async_wait(handler1); 
+    m_pThread = new boost::thread(&Mytimer::runTimerThread, this);
 }

 bool Mytimer::isRunning()

这导致了预期的行为

mbp:stackoverflow samm$ ./a.out
20120413 11:17:22922529 before timer construction
20120413 11:17:22923155 before startTimer()
20120413 11:17:22923530 IsRunning: 1
20120413 11:17:23924702 IsRunning: 1
20120413 11:17:24925971 IsRunning: 1
20120413 11:17:25927320 IsRunning: 1
20120413 11:17:26928715 IsRunning: 1
20120413 11:17:27929969 IsRunning: 1
20120413 11:17:28930601 IsRunning: 1
20120413 11:17:29931843 IsRunning: 1
20120413 11:17:30933098 IsRunning: 1
20120413 11:17:31934366 IsRunning: 0
20120413 11:17:32923594 Handler1: expired.
20120413 11:17:32934692 IsRunning: 0
20120413 11:17:33935922 IsRunning: 0
20120413 11:17:34936638 IsRunning: 0
20120413 11:17:35937905 IsRunning: 0
20120413 11:17:36939133 IsRunning: 0
20120413 11:17:37940407 IsRunning: 0
20120413 11:17:38941043 IsRunning: 0
20120413 11:17:39942319 IsRunning: 0
20120413 11:17:40942662 IsRunning: 0
20120413 11:17:41943989 IsRunning: 0
20120413 11:17:42945284 IsRunning: 0
20120413 11:17:43946555 IsRunning: 0
mbp:stackoverflow samm$
于 2012-04-13T16:20:36.443 回答
1

下面的代码现在有正确的deadline_timer初始化，并且有一个私有的bool标志，它允许确定定时器当前是否正在运行。它还有一个成员本地处理程序。

class Mytimer {
public:
    Mytimer();
    void startTimer(int timeDelaySecs);
    void cancelTimer();
    void runTimerThread();
    bool isRunning();
    void timerHandler(const boost::system::error_code& ec); 
private:
    bool m_isRunning;
    boost::asio::deadline_timer* m_pTimer;
    boost::thread* m_pThread;
};

Mytimer::Mytimer()
    : m_pTimer(NULL),
      m_pThread(NULL)
{
    m_pTimer = new boost::asio::deadline_timer(io_service1); 
}

void Mytimer::runTimerThread()
{
    io_service1.run();
}

void Mytimer::startTimer(int timeDelaySecs)
{
    m_pTimer->expires_from_now(boost::posix_time::seconds(timeDelaySecs));
    m_pTimer->async_wait(boost::bind(&Mytimer::timerHandler, this, _1)); 
    m_pThread = new boost::thread(&Mytimer::runTimerThread, this);
    m_isRunning = true;
}

bool Mytimer::isRunning()
{
    return m_isRunning;
}

void Mytimer::timerHandler(const boost::system::error_code& ec) 
{ 
    if (ec == boost::asio::error::operation_aborted)
    {
        std::cout << microsec_clock::local_time() << " Handler1: Timer 1 was cancelled or retriggered." << std::endl; 
    }
    else
    {
        std::cout << microsec_clock::local_time() << " Handler1: expired." << std::endl; 
    }
    m_isRunning = false;
}
于 2012-04-15T19:12:00.717 回答