Here

double GetSeconds();
{
	LARGE_INTEGER		   t;
	FILETIME				f;
	double				  microseconds;
	static LARGE_INTEGER	offset;
	static double		   FrequencyToMicroseconds;
	static int			  initialized = 0;
	static BOOL			 UsePerformanceCounter = 0;

	if ( !initialized )
	{
		LARGE_INTEGER performanceFrequency;
		initialized = 1;
		UsePerformanceCounter = QueryPerformanceFrequency( &performanceFrequency );
		if ( UsePerformanceCounter )
		{
			QueryPerformanceCounter( &offset );
			FrequencyToMicroseconds = ( double )performanceFrequency.QuadPart / 1000000.;
		}
		else
		{
			offset = getFILETIMEoffset();
			FrequencyToMicroseconds = 10.;
		}
	}
	if ( UsePerformanceCounter )
		QueryPerformanceCounter( &t );
	else
	{
		GetSystemTimeAsFileTime( &f );
		t.QuadPart = f.dwHighDateTime;
		t.QuadPart <<= 32;
		t.QuadPart |= f.dwLowDateTime;
	}

	t.QuadPart -= offset.QuadPart;
	microseconds = ( double )t.QuadPart / FrequencyToMicroseconds;
	t.QuadPart = microseconds;
	tv->tv_sec = t.QuadPart / 1000000;
	tv->tv_usec = t.QuadPart % 1000000;

	return (double)(tv->tv_nsec / CLOCKS_PER_SEC) / 1000.0 + (double)tv->tv_sec;
}