C语言下如何实现微秒级延时，我用循环和Sleep最小是 15或16毫秒

[RedSunIT]

dwBegin = GetSamBeginTime();

for( i=0;i<10000;i++)
{
dwCounts--;
}
或 Sleep(1)

dwEnd = GetTickCount();
dwCount = dwEnd - dwBegin;

得到的是 dwCount 是15或16，　要么就为0，　　怎么也不能精确到1

请问有什么方法么？

[doomgnu]

#include <windows.h>
#include <time.h>
#include <stdio.h>


ULONG GetTimeDis(struct tm first, struct tm second) //计算两次时间差
{
return abs((first.tm_hour * 3600 + first.tm_min * 60 + first.tm_sec)
- (second.tm_hour * 3600 + second.tm_min * 60 + second.tm_sec));
}

void Delay(ULONG ulMicroSeconds)
{
LARGE_INTEGER timeStop;
LARGE_INTEGER timeStart;
LARGE_INTEGER Freq;
ULONG ulTimeToWait;

if (!QueryPerformanceFrequency( &Freq ))
return;

ulTimeToWait = Freq.QuadPart * ulMicroSeconds / 1000 / 1000;

QueryPerformanceCounter ( ×tart );

timeStop = timeStart;

while( timeStop.QuadPart - timeStart.QuadPart < ulTimeToWait )
{
QueryPerformanceCounter( ×top );
}
}



int main(void)
{
struct tm timeStart, timeEnd;

_getsystime(×tart);


Delay(1000 * 1000 * 3); //3秒


_getsystime(&timeEnd);
printf("用时：%d秒\n", GetTimeDis(timeStart, timeEnd));

return 0;
}

[vann1982]

给个文章看看
http://blog.csdn.net/sunboy_2050/article/details/5019144

[ndy_w]

循环可以用PerformanceCounter得到较为精确的时间。Sleep的话是不行的。每个线程有时间片，再次唤醒得到cpu一般就超过10毫秒了。