Windows system time (filetime and systemtime)

Reprinted please indicate the source, original address: http://blog.csdn.net/morewindows/article/details/8654298

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The previous summary of various timing functions in Windows introduces five common timing functions-time () and clock () in Standard C/C ++ (), in Windows, the API interfaces are timegettime (), gettickcount (), and queryperformancecounter (). The following describes the two structures of time in Windows: filetime and systemtime and related functions.

 

Let's take a look at the definitions of these two struct types:

1. filetime

// By morewindows-(http://blog.csdn.net/MoreWindows)

Typedef struct _ filetime {

Dworddwlowdatetime;

Dworddwhighdatetime;

} Filetime, * pfiletime, * lpfiletime;

Its Description on msdn -- contains a 64-bit value representing the number of 100-nanosecond intervals since January 1, 1601 (UTC ).

2. systemtime

// By morewindows-(http://blog.csdn.net/MoreWindows)

Typedef struct _ systemtime {

Wordwyear;

Wordwmonth;

Wordwdayofweek;

Wordwday;

Wordwhour;

Wordwminute;

Wordwsecond;

Wordwmilliseconds;

} Systemtime, * psystemtime, * lpsystemtime;

This does not need to be explained. Like the method that we usually use to represent time, it is a date (year-month-day) plus time (hour: minute: second)

 

The two struct-related functions mainly include getsystemtime, getlocaltime, systemtimetofiletime, filetimetosystemtime, localfiletimetofiletime, and filetimetolocalfiletime. Let's take a look at the usage of these functions:

1. Get the current UTC time

// By morewindows-(http://blog.csdn.net/MoreWindows)

Void getsystemtime (lpsystemtimelpsystemtime );

2. Get the local time

Void getlocaltime (lpsystemtimelpsystemtime );

 

3. Convert systemtime to filetime

// By morewindows-(http://blog.csdn.net/MoreWindows)

Boolsystemtimetofiletime (

Const systemtime * lpsystemtime,

Lpfiletimelpfiletime

);

4. Convert filetime to systemtime

Boolfiletimetosystemtime (

Const filetime * lpfiletime,

Lpsystemtimelpsystemtime

);

 

5. convert local time to UTC time

// By morewindows-(http://blog.csdn.net/MoreWindows)

Boollocalfiletimetofiletime (

Const filetime * lplocalfiletime,

Lpfiletimelpfiletime

);

6. Convert UTC time to local time

Boolfiletimetolocalfiletime (

Const filetime * lpfiletime,

Lpfiletimelplocalfiletime

);

 

An example is provided below. This example mainly uses two functions:

1. Obtain the current local system time

2. Open a file and change the file creation time, modification time, and access time from the filetime type to the systemtime type.

The complete code is as follows:

// Windows system time (filetime and systemtime) // By morewindows-(http://blog.csdn.net/morewindows/article/details/8654298) # include <windows. h> # include <stdio. h> # include <conio. h> class cwindowsdateandtime {public: static void getcurrentlocalsystemtime (char * pstrdate, char * pstrtime); static void filetimetolocalsystemtime (filetime & ft, char * pstrdate, char * pstrtime );}; // obtain the current local time void cwindowsdateandtime: getcurre Ntlocalsystemtime (char * pstrdate, char * pstrtime) {systemtime st; getlocaltime (& St); If (pstrdate! = NULL) sprintf (pstrdate, "% d-% d", st. wyear, st. wmonth, st. wday); If (pstrtime! = NULL) sprintf (pstrtime, "% 02d: % 02d: % 02d", St. whour, St. wminute, St. wsecond);} // convert the file time to the local time void cwindowsdateandtime: filetimetolocalsystemtime (filetime & ft, char * pstrdate, char * pstrtime) {filetime localft; filetimetolocalfiletime (& ft, & localft); systemtime st; filetimetosystemtime (& localft, & St); If (pstrdate! = NULL) sprintf (pstrdate, "% d-% d", st. wyear, st. wmonth, st. wday); If (pstrtime! = NULL) sprintf (pstrtime, "% 02d: % 02d: % 02d", St. whour, St. wminute, St. wsecond);} int main (INT argc, char * argv []) {printf ("Windows system time (filetime and systemtime) \ n "); printf ("-- by morewindows (http://blog.csdn.net/morewindows/article/details/8654298) -- \ n"); const int max_len = 30; char strdate [max_len], strtime [max_len]; cwindowsdateandtime :: getcurrentlocalsystemtime (strdate, strtime); printf ("Current System Time: % S % s \ n", strdate, strtime); const char * pstrfilename = "d :\\ morewindows.txt "; printf ("file % s: \ n", pstrfilename); handle handlefile = createfile (pstrfilename, generic_read, file_assist_read, null, open_existing, 0, null); filetime ftcreationtime, encrypted, ftlastwritetime; getfiletime (handlefile, & ftcreationtime, & expires, & ftlastwritetime); cwindowsdateandtime: filetimetolocalsystemtime (ftcreationtime, strdate, strtime); printf ("Creation Time: % S % s \ n ", strdate, strtime); cwindowsdateandtime: filetimetolocalsystemtime (ftlastaccesstime, strdate, strtime); printf (" Access time: % S % s \ n ", strdate, strtime); cwindowsdateandtime: filetimetolocalsystemtime (ftlastwritetime, strdate, strtime); printf ("modification time: % S % s \ n", strdate, strtime); getch (); return 0 ;}

The program running result is as follows:

 

Reprinted please indicate the source, original address: http://blog.csdn.net/morewindows/article/details/8654298

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