Return Values The return value is the number of milliseconds that have elapsed since the system was started. Res The elapsed time is stored as a DWORD value. Therefore, the time will wrap around to zero if the system is run continuously for 49.7 days. If you need a higher resolution timer, use a multimedia timer or a high-resolution timer. Windows NT/2000: To obtain the time elapsed since the computer was started, retrieve the System Up Time counter in the performance data in the registry key HKEY_PERFORMANCE_DATA. The value returned is an 8-byte value. For more information, see Performance
就可以计算某个时刻的时间了，两个时间一减就是处理时间
The return value is the number of milliseconds that have elapsed since the system was started. Res
The elapsed time is stored as a DWORD value. Therefore, the time will wrap around to zero if the system is run continuously for 49.7 days. If you need a higher resolution timer, use a multimedia timer or a high-resolution timer. Windows NT/2000: To obtain the time elapsed since the computer was started, retrieve the System Up Time counter in the performance data in the registry key HKEY_PERFORMANCE_DATA. The value returned is an 8-byte value. For more information, see Performance