如何使用QueryPerformanceCounter在几秒钟内获得结果？

Question

BOOL QueryPerformanceCounter(
__out LARGE_INTEGER *lpPerformanceCount 
); 

LARGE_IN 
TEGER startTimer() 
{ 
LARGE_INTEGER start; 
DWORD_PTR oldmask = SetThreadAffinityMask(GetCurrentThread(), 0); 
QueryPerformanceCounter(&start); 
SetThreadAffinityMask(GetCurrentThread(), oldmask); 
return 
start; 
} 

LARGE_INTEGER endTimer() 
{ 
LARGE_INTE 
GER stop; 
DWORD_PTR oldmask = SetThreadAffinityMask(GetCurrentThread(), 0); 
QueryPerformanceCounter(&stop); 
SetThreadAffinityMask(GetCurrentThread(), oldmask); 
return 
stop; 
} 

我正在使用这些函数，但我不确定它返回值的类型。 endTimer - startTimer =？如何将此结果转换为秒？

Answer 1

您需要获取频率并将其分为2个计数器。

LARGE_INTEGER fr,t1,t2; 

QueryPerformanceCounter(&t1); 

// some lengthy code ... 

QueryPerformanceCounter(&t2); 

QueryPerformanceFrequency(&fr); 

double diff_sec = (t2.QuadPart-t1.QuadPart)/(double)fr.QuadPart;