如何在不使用 sleep() 的情况下让 function 在循环内休眠？

Question

I'm trying to add a randomly generated number to a calculation but I don't want the randomly generated number to be randomly generated every 1ms (because that's how my try functions needs to run) and I can't use sleep() because it would sleep the entire process (my whole program).

I've tried to sleep the randomnumbergenerator function every 1 second but the try do makes it run every 1ms, how can I sleep a function inside of a loop without using sleep()?

Current code:

int randomnumber = 0;

void randomnumbergenerator()
{
    for (;;)
    {
        std::this_thread::sleep_for(std::chrono::seconds(1));
        int min = -1000;
        int max = +2000;
        int randomNum = rand() % max + (min);
        randomnumber = randomNum;
    }
}

try //this must run every 1 ms;
{
    do
    {
        if (something)
        {
            std::thread(randomnumbergenerator).detach();
            const int somenumber2 = something;
            const int somenumber = something;
            somenumber += somenumber2 * randomnumber ;
        }
    }
}

Answer 1

This is what worked for me:

uintptr_t milliseconds_now() {
    static LARGE_INTEGER s_frequency;
    static BOOL s_use_qpc = QueryPerformanceFrequency(&s_frequency);
    if (s_use_qpc) {
        LARGE_INTEGER now;
        QueryPerformanceCounter(&now);
        return (1000LL * now.QuadPart) / s_frequency.QuadPart;
    }
    else {
        return GetTickCount64();
    }
}

int randomrumber = 0;

void fn()
{
    for (;;)
    {
        std::this_thread::sleep_for(std::chrono::seconds(4));
        int min = -1000;
        int max = +2000;
        int randomNum = rand() % max + (min);
        randomrumber = randomNum;
    }
}

try //this must run every 1 ms;
{
    do
    {
        if (something)
        {
            static std::uintptr_t desiredTime = 0;
            if (milliseconds_now() >= desiredTime)
            {
                std::thread(fn).detach();
                desiredTime = milliseconds_now() + 5000;
            }

            const int somenumber2 = something;
            const int somenumber = something;
            somenumber += somenumber2 * randomnumber ;
        }
    }
}

This solution isn't perfect tho. It makes my program lose some abilities. Probably because it's not multithreaded.