c++使用线程作为定时器

发布于 2024-11-24 10:29:00 字数 552 浏览 10 评论 0原文

我的项目有一个不同的线程来制作一些东西。

没关系，但我希望每 20 毫秒调用一些函数（例如），但考虑到该函数花费的时间...我尝试更好地解释...我调用该函数，该函数花了 6 毫秒退出，所以我希望线程休眠 14 毫秒（20 - 6），下次调用时，该函数花费 12 毫秒，因此休眠时间仅为 8 毫秒.... 我该怎么做？这是我的代码：

// thread constructor
DWORD dwThreadId, dwThrdParam = 1;  
HANDLE thread = CreateThread( NULL, 0, (LPTHREAD_START_ROUTINE)workerFunc, &dwThrdParam, 0, &dwThreadId );

// thread function
DWORD WINAPI workerFunc( LPDWORD lpdwParam )
{
    while( true )
    {
        myFunction( );
        Sleep( ??? );
    }
    return 0;
}

谢谢！

原文

I have my project with a different thread that make some stuff.

It's all ok, but I wish have some function called each 20ms (for example), but considering the time spent to the function... I try to explain better... I call the function, and the function spent 6ms to exit, so I wish that the thread sleeps 14ms (20 - 6), the next time that is called, the function spent 12ms, so the sleep will be only 8ms....
how can I do this?
here is my code:

// thread constructor
DWORD dwThreadId, dwThrdParam = 1;  
HANDLE thread = CreateThread( NULL, 0, (LPTHREAD_START_ROUTINE)workerFunc, &dwThrdParam, 0, &dwThreadId );

// thread function
DWORD WINAPI workerFunc( LPDWORD lpdwParam )
{
    while( true )
    {
        myFunction( );
        Sleep( ??? );
    }
    return 0;
}

thanks!

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柏拉图鍀咏恒 2024-12-01 10:29:00

这个怎么样：

clock_t start, end;
while( true )
{
    start = clock();
    myFunction( );
    end = clock();
    Sleep(20-(end-start)*CLOCKS_PER_SEC/1000.0);
}

What about this:

clock_t start, end;
while( true )
{
    start = clock();
    myFunction( );
    end = clock();
    Sleep(20-(end-start)*CLOCKS_PER_SEC/1000.0);
}

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清风夜微凉 2024-12-01 10:29:00

一种简单的方法是让线程休眠一段可变的时间：

void periodic_function()
{
  /* function body */

  timestamp = get_time(); // pseudo-function
  remaining_sleep_time = std::min(0, 20 - (timestamp - last_timestamp));
  last_timestamp = timestamp;
  milli_sleep_callback(remaining_sleep_time, periodic_function);
}

您需要一个适合 get_time() 的稳定时钟函数和一个 sleep 函数 - 尝试 < chrono> 或标头。在这个例子中，我假设你有一个计时器回调（就像在 boost.ASIO 中），但你也可以创建一个无限循环或类似的东西。

如果函数体从未超过 20 毫秒，则此函数将起作用，但如果您的函数花费的时间更长，它会快速赶上。如果你想同步到全局 20 毫秒节奏，你必须添加另一个全局计步器或类似的东西。

A simple approach would be to send the thread to sleep for a variable amount of time:

void periodic_function()
{
  /* function body */

  timestamp = get_time(); // pseudo-function
  remaining_sleep_time = std::min(0, 20 - (timestamp - last_timestamp));
  last_timestamp = timestamp;
  milli_sleep_callback(remaining_sleep_time, periodic_function);
}

You'll need a suitable steady clock function for get_time() and a sleep function - try the <chrono> or <tr1/chrono> header. In this example I've assumed that you have a timer callback (like in boost.ASIO), but you could also make an infinite loop or something like that.

This function will work if the function body never exceeds 20ms, though it'll do a quick catch-up if your function ever takes longer. If you want to synchronize to a global 20ms rhythm, you'd have to add another global step counter or something like that.

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