Sleep 函数的一种实现

最新推荐文章于 2022-05-13 18:35:41 发布

原创最新推荐文章于 2022-05-13 18:35:41 发布 · 650 阅读

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精度大约 1ms，但是毕竟还是有误差的

#include <stdio.h>
#include <Windows.h>

class CMySleep {
public:
    CMySleep() {
        InitializeConditionVariable(&cv);
        InitializeCriticalSection(&cs);
    }
    ~CMySleep() {
        DeleteCriticalSection(&cs);
    }
    void operator()(DWORD nTime) {
        SleepConditionVariableCS(&cv, &cs, nTime);
    }
private:
    CONDITION_VARIABLE cv;
    CRITICAL_SECTION cs;
};

struct TimerStrcut {
    LARGE_INTEGER nFreq;
    LARGE_INTEGER nBeginTime;
    LARGE_INTEGER nEndTime;
};

class Timer {
public:
    Timer() {
        QueryPerformanceFrequency(&m_time.nFreq);
    }
    void Start() {
        QueryPerformanceCounter(&m_time.nBeginTime);
    }
    void End() {
        QueryPerformanceCounter(&m_time.nEndTime);
    }

    double GetTime() {
        return (double)(m_time.nEndTime.QuadPart-m_time.nBeginTime.QuadPart) / (double)(m_time.nFreq.QuadPart); 
    }

private:
    TimerStrcut m_time;
};

int main() {
    CMySleep mySleep;
    Timer time1;
    time1.Start();
    Sleep(1000);
    time1.End();
    printf("%.20lf\n", time1.GetTime());

    time1.Start();
    mySleep(1000);
    time1.End();
    printf("%.20lf\n", time1.GetTime());

    return 0;
}