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Problem with GetTickCount on Linux [message #36465]

Wed, 30 May 2012 11:38

steffen
Messages: 38
Registered: May 2007
Location: Denmark

Member

Hi,
On my embedded system I'm using a GPS to correct the system time and I found that adjusting the realtime clock on a posix system, cripples all the timer functions in Upp.

The Posix standard has added some clock_xxx functions to handle timers.
This gives a much better solution than the gettimeofday call used today.

Here is an updated function with fallback to the current gettimeofday call.

In Core/Util.cpp:

#ifdef PLATFORM_POSIX
dword GetTickCount() {
#if _POSIX_C_SOURCE >= 199309L
	struct timespec tp;
	if (clock_gettime(CLOCK_MONOTONIC, &tp) == 0)
	{
		return (dword)((tp.tv_sec * 1000) + (tp.tv_nsec / 1000000));
	}
	return 0; // ?? (errno is set)
#else
	struct timeval tv[1];
	struct timezone tz[1];
	memset(tz, 0, sizeof(tz));
	gettimeofday(tv, tz);
	return (dword)tv->tv_sec * 1000 + tv->tv_usec / 1000;
#endif
}
#endif

In Core/TimeDate.cpp there is a GetSysTime, but I was missing a SetSysTime also.
Here is one that can be called from a program with administrator privileges:

bool SetSysTime(Time &ATime)
{
#ifdef PLATFORM_POSIX
	struct tm      tmp_time;
	tmp_time.tm_sec  = ATime.second;
	tmp_time.tm_min  = ATime.minute;
	tmp_time.tm_hour = ATime.hour;
	tmp_time.tm_mday = ATime.day;
	tmp_time.tm_mon  = ATime.month-1;
	tmp_time.tm_year = ATime.year-1900;
	time_t raw_time  = mktime(&tmp_time);

	struct timespec sys_time;
	sys_time.tv_sec  = raw_time;
	sys_time.tv_nsec = 0;

	int result = clock_settime(CLOCK_REALTIME, &sys_time);
	return (result == 0);
#endif
#ifdef PLATFORM_WIN32
	SYSTEMTIME systime;
	systime.wYear	= ATime.year;
	systime.wMonth	= ATime.month;
	systime.wDay	= ATime.day;
	systime.wHour	= ATime.hour;
	systime.wMinute	= ATime.minute;
	systime.wSecond	= ATime.second;
	systime.wDayOfWeek = 0;
	systime.wMilliseconds = 0;
	return SetSystemTime( &systime );
#endif
}

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