经过5分钟后发生了一些事情，而其他代码仍在C ++中运行 [英] Make something happen after 5 minutes has passed, while other code still runs in C++

问题描述

我试图做一个计时器，所以五分钟后发生了一些事情.问题是，在不断检查计时器时，我需要其他代码才能运行.我在下面创建了一个示例，该示例显示了实际代码的外观，带有计时器的函数在类中，因此我在下面做了同样的事情.这是代码:

I am trying to make a timer, so after five minutes something happens. The catch is that while the timer is being checked constantly I need other code to be running. I have created a sample below, of how the actually code looks, the function with the timer is in class, so I did the same thing below. Here is the code:

此代码假定包含所有必需的标头

Class.h:

class MyClass
{
public:
    void TimerFunc(int MSeconds);
};

void MyClass::TimerFunc(int MSeconds)
{
    Sleep(MSeconds); //Windows.h
    //Event code
    return;
}

Main.cpp:

int main()
{
    MyClass myClass;
    myClass.TimerFunc(300); //300 is 5 minutes

    //Here we do not want to wait for the five minutes to pass,
    //instead we want to continue the rest of the code and check
    //for user input as below
    std::cout << "This should print before the Event Code happens.";
}

这里的问题是代码等待五分钟，然后继续.我不确定线程​​在这里是否会是一个好选择，我之前没有做太多事情，如果有人可以帮助我或者知道更好的解决方法，那么任何帮助都是值得的.

The problem here is that the code waits for the five minutes to pass, and then continues. I'm not sure if threading would be a good option here, I haven't done much with it before, if anyone could help me with that, or knows a better way to go about it, any help is appreciated.

推荐答案

对于C ++ 11线程，这将像这样工作:

With C++11 threads, this would work like this:

int main()
{
    MyClass myClass;
    thread ti([](MyClass &m){m.TimerFunc(300); }, ref(myClass));   // create and launch thread 

    // ... code executed concurrently to threaded code

    ti.join();             // wait for the thread to end (or you'll crash !!)
}

将私人成员添加到您的班级:

Add a private member to your class:

     atomic<bool> run=true;   // designed to avoid race issue with concurrent access 

将其计时器功能更新为在此变量为true时循环:

Update its timer function to loop while this variable is true:

void MyClass::TimerFunc(int MSeconds)
{
    while (run) {
        this_thread::sleep_for(chrono::milliseconds(MSeconds));  // standard sleep instead of microsoft's one
        //Event code
    }
    return;
}

预见该类中的成员函数将停止线程循环:

Foresee within the class a member function to stop the threaded loop:

void Stop() {
    run = false;
}

当不再需要计时器功能时(例如，在调用 ti.join()<之前)，最后更新 main()以调用 myClass.Stop()/code>)

Finally update main() to call myClass.Stop() when the timer function is no longer needed (i.e. before calling ti.join() )

注意，避免讨厌的错误:请小心在线程构造函数中引用 ref(myClass).如果您忘记了这一点，线程 ti 将使用对myClass副本的引用，而不是原始对象.

attention, nasty error to avoid: be careful to refer to ref(myClass) in the thread constructor. If you would forget this, the thread ti would use a reference to a copy of myClass instead of the original object.

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