C/C++实战 - 获取当前时间的毫秒表示

struct timezone {
	int tz_minuteswest;
	int tz_dsttime;
};

int gettimeofday(struct timeval *tv, struct timezone *tz) {
	if (tv) {
		FILETIME filetime; /* 64-bit value representing the number of 100-nanosecond intervals since
		                      January 1, 1601 00:00 UTC */
		ULARGE_INTEGER x;
		ULONGLONG usec;
		static const ULONGLONG epoch_offset_us =
		    11644473600000000ULL; /* microseconds betweeen Jan 1,1601 and Jan 1,1970 */

#if _WIN32_WINNT >= _WIN32_WINNT_WIN8
		GetSystemTimePreciseAsFileTime(&filetime);
#else
		GetSystemTimeAsFileTime(&filetime);
#endif
		x.LowPart = filetime.dwLowDateTime;
		x.HighPart = filetime.dwHighDateTime;
		usec = x.QuadPart / 10 - epoch_offset_us;
		tv->tv_sec = time_t(usec / 1000000ULL);
		tv->tv_usec = long(usec % 1000000ULL);
	}
	if (tz) {
		TIME_ZONE_INFORMATION timezone;
		GetTimeZoneInformation(&timezone);
		tz->tz_minuteswest = timezone.Bias;
		tz->tz_dsttime = 0;
	}
	return 0;
}

uint64_t currentTimeInMicroSeconds() {
	struct timeval time;
	gettimeofday(&time, NULL);
	return uint64_t(time.tv_sec) * 1000 * 1000 + time.tv_usec;
}