c++ - Handling Interrupt in C++

Question

I am writing a framework for an embedded device which has the ability to run multiple applications. When switching between apps how can I ensure that the state of my current application is cleaned up correctly? For example, say I am running through an intensive loop in one application and a request is made to run a second app while that loop has not yet finished. I cannot delete the object containing the loop until the loop has finished, yet I am unsure how to ensure the looping object is in a state ready to be deleted. Do I need some kind of polling mechanism or event callback which notifies me when it has completed?

Thanks.

Answer 1

通常，如果您需要执行此类操作，您将拥有一个可以处理多个任务的 OS/RTOS（即使操作系统是简单的自制类型的东西）。

如果您还没有 RTOS，您可能想研究一个（有数百个可用）或考虑合并一些简单的东西，如 protothreads：http ://www.sics.se/~adam/pt/

Answer 2

所以你有两个线程：一个运行内核，一个运行应用程序？您需要在内核中创建一个函数，说 ReadyToYield()，应用程序可以在您愿意关闭它时调用它。ReadyToYield() 将标记内核线程以向其提供好消息，然后坐下来等待内核线程决定要做什么。它可能看起来像这样：

volatile bool appWaitingOnKernel = false;
volatile bool continueWaitingForKernel;

在应用程序线程调用上：

void ReadyToYield(void)
{
    continueWaitingForKernel = true;
    appWaitingOnKernel = true;
    while(continueWaitingForKernel == true);
}

在内核线程调用上：

void CheckForWaitingApp(void)
{
    if(appWaitingOnKernel == true)
    {
        appWaitingOnKernel = false;

        if(needToDeleteApp)
            DeleteApp();
        else
            continueWaitingForKernel = false;
    }
}

显然，这里的实际实现取决于底层的 O/S，但这是要点。

约翰。

Answer 3

(1) 你需要编写线程安全的代码。这并不特定于嵌入式系统。

(2) 进行上下文切换时需要将状态保存起来。