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The gettimeofday() function obtains the current time, expressed as seconds and microseconds since the Epoch, and store it in the timeval structure pointed to by tv. As posix says gettimeoday should return zero and should not reserve any value for error, this function returns zero. Here is the program, I?ve given definition struct timezeone and for others I didn?t give as all other data types definitions are available in windows include files itself.

#include < time.h >
 
#if defined(_MSC_VER) || defined(_MSC_EXTENSIONS)
  #define DELTA_EPOCH_IN_MICROSECS  11644473600000000Ui64
#else
  #define DELTA_EPOCH_IN_MICROSECS  11644473600000000ULL
#endif
 
struct timezone 
{
  int  tz_minuteswest; /* minutes W of Greenwich */
  int  tz_dsttime;     /* type of dst correction */
};
 
int gettimeofday(struct timeval *tv, struct timezone *tz)
{
  FILETIME ft;
  unsigned __int64 tmpres = 0;
  static int tzflag;
 
  if (NULL != tv)
  {
    GetSystemTimeAsFileTime(&ft);
 
    tmpres |= ft.dwHighDateTime;
    tmpres <<= 32;
    tmpres |= ft.dwLowDateTime;
 
    /*converting file time to unix epoch*/
    tmpres /= 10;  /*convert into microseconds*/
    tmpres -= DELTA_EPOCH_IN_MICROSECS; 
    tv->tv_sec = (long)(tmpres / 1000000UL);
    tv->tv_usec = (long)(tmpres % 1000000UL);
  }
 
  if (NULL != tz)
  {
    if (!tzflag)
    {
      _tzset();
      tzflag++;
    }
    tz->tz_minuteswest = _timezone / 60;
    tz->tz_dsttime = _daylight;
  }
 
  return 0;
}

usage:

struct timeval now; struct timezone tzone;

gettimeofday(&now, NULL);

gettimeofday(&now, &tzone);

download [gettimeofday.c] program..

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Related Blog Items

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This entry was written by ponnada and posted on December 26, 2006 at 12:05 pm and filed under C Tidbits, Windows Application Programming. Bookmark the permalink. Follow any comments here with the RSS feed for this post. Post a comment or leave a trackback: Trackback URL.