计算线程执行某个任务需要的时间——来自《Windows核心编程》

__int64 FIleTimeToQuadWord(PFILETIME pft){
return(Int64ShllMod32(pft->dwHighDateTime, 32)|pft->dwLowDateTime);
}

void PerformLongOperation(){
PFILETIME ftKernelTimeStart, ftKernelTimeEnd;
PFILETIME ftUserTimeStart, ftUserTimeEnd;
PFILETIME ftDummy;
__int64 qwKernelTimeElapsed, qwUserTimeElapsed, qwTotalTimeElapsed;

// Get starting times.
GetThreadTimes(GetCurrentThread(), &ftDummy， &ftDummy, &ftKernelTimeStart, &ftKernelTimeStart);

// Perform complex algorithm here.

// Get ending time.
GetThreadTimes(GetCurrentThread(), &ftDummy， &ftDummy, &ftKernelTimeEnd, &ftKernelTimeEnd);

// Get the elapsed kernel and user times by converting the start and end times from FILETIMEs to quad words,
// and then subtract the start times from the end times.
qwKernelTimeElapsed = FileTimeToQuadWord(&ftKernelTimeEnd) - FileTimeToQuadWord(&ftKernelTimeStart);
qwUTimeElapsed = FileTimeToQuadWord(&ftUserTimeEnd) - FileTimeToQuadWord(&ftUserTimeStart);

// Get total time duration by adding the kernel and user times.
qwTotalTimeElapsed = qwKernelTimeElapsed + qwUserTimeElapsed;

// The total wlapsed time is in qwTotalTimeElapsed.

}