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

最新推荐文章于 2021-05-21 16:23:13 发布

最新推荐文章于 2021-05-21 16:23:13 发布 · 449 阅读

本文介绍了如何使用SystemTimeToFileTime函数将SYSTEMTIME结构体转换为FILETIME结构体，并通过ULARGE_INTEGER进行时间差值的计算。

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.

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;