获得两个SYSTEMTIME变量之间的差异

Question

例如我的代码如下。

void main()

{

       SYSTEMTIME LocalTime_Start = { 0 };

        GetLocalTime( &LocalTime_Start );

        SYSTEMTIME LocalTime_End = { 0 };
        // Some program Statements

         GetLocalTime( &LocalTime_End );

         // Now i want difference of two i.e.
         // can i do as following
         SYSTEMTIME localTime_diff = LocalTime_End - LocalTime_Start;
         // guys please let me know how to achieve that asap...thanks a lot in advance
}

Answer 1

使用

将SYSTEMTIME结构转换为FILETIME

FILTETIME ft;
::SystemTimeToFileTime(&sysTime, &ft);

使用以下方法将FILETIME转换为ULONGLONG：

ULARGE_INTEGER uli;
uli.LowPart = ft.dwLowDateTime ;
uli.HighPart= ft.dwHighDateTime;
ULONGLONG uft= uli.QuadPart;

减去ULONGLONG以获得HectoNanoSec的时差