Windows中如何计算时间间隔(2)使用SYSTEMTIME和FILETIME

SYSTEMTIME和FILETIME是两个结构体，定义如下：

typedef struct _SYSTEMTIME { 
  WORD wYear; 
  WORD wMonth; 
  WORD wDayOfWeek; 
  WORD wDay; 
  WORD wHour; 
  WORD wMinute; 
  WORD wSecond; 
  WORD wMilliseconds; 
} SYSTEMTIME;

This structure is a 64-bit value representing the number of 100-nanosecond intervals since January 1, 1601.

typedef struct _FILETIME { 
  DWORD dwLowDateTime; 
  DWORD dwHighDateTime; 
} FILETIME; 

Members

 
 

  
  
   
   dwLowDateTime 
  
  
  
  

   
   Specifies the low 32 bits of the Win32 date/time value. 
  
  
  
  
   
   dwHighDateTime 
  
  
  
  

   
   Specifies the upper 32 bits of the Win32 date/time value.
  
  
 
 

获取相对时间的常用方法如下，.

The following list shows tasks to perform instead:

• 使用SystemTimeToFileTime()转换SYSTEMTIME 为 FILETIME 结构.
• 将FILETIME 的值赋给 ULARGE_INTEGER
• 使用ULARGE_INTEGER中的64位值计算差值。

typedef union _ULARGE_INTEGER {
  struct {
    DWORD LowPart;
    DWORD HighPart;
  };
  struct {
    DWORD LowPart;
    DWORD HighPart;
  } u;
  ULONGLONG QuadPart;
} ULARGE_INTEGER, 
*PULARGE_INTEGER;

 

Members

LowPart

Low-order 32 bits.

HighPart

High-order 32 bits.

u

LowPart

Low-order 32 bits.

HighPart

High-order 32 bits.

QuadPart

Unsigned 64-bit integer.

 

代码如下：

SYSTEMTIME sTime1;
SYSTEMTIME sTime2;
...
...

ULARGE_INTEGER fTime1;/*FILETIME*/
ULARGE_INTEGER fTime2;/*FILETIME*/


SystemTimeToFileTime(&sTime1,(FILETIME*)&fTime1);
SystemTimeToFileTime(&sTime2,(FILETIME*)&fTime2);

unsigned __int64 dft=fTime2.QuadPart-fTime1.QuadPart;