timer device problem with GetSysTime()

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Mon, 2021-09-13 14:28

walkero

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Joined: 2009-05-03 16:54

timer device problem with GetSysTime()

I don't know if you had the same issue before, but I am using GetSysTime() to get the system date, and more specifically, the seconds number. This returns a 10 digit timestamp of the current date, or at least it should return that.

What I get is the right day, month and hour of the moment I run it, but minus 8 years. Of' course, the time on my system is synced and shows the right date, bit the GetSysTime() keeps giving a wrong year.

I use it at the following method:

STRPTR now(void)
{
  uint8 timestampLen = 12;
  STRPTR buf = IExec->AllocVecTags(sizeof(char) * timestampLen,
      AVT_Type,            MEMF_SHARED,
      AVT_ClearWithValue,  "\0",
      TAG_DONE);
  struct TimeVal tv;
 
  ITimer->GetSysTime(&tv);
  IUtility->SNPrintf(buf, sizeof(char) * timestampLen, "%lu", tv.Seconds);
 
  return buf;
}

And below you can see how I initiate and open the timer device

  TimerMP = IExec->AllocSysObject(ASOT_PORT, NULL);
  if (TimerMP != NULL)
  {
    TimeReq = IExec->AllocSysObjectTags(ASOT_IOREQUEST,
        ASOIOR_Size,        sizeof(struct TimeRequest),
        ASOIOR_ReplyPort,   TimerMP,
        TAG_END);
 
    if (TimeReq != NULL)
    {
      if (!IExec->OpenDevice("timer.device", UNIT_VBLANK, (struct IORequest *)TimeReq, 0))
      {
        if ((TTimerBase = (struct Library *)TimeReq->Request.io_Device))
        {
          ITimer = (struct TimerIFace *)IExec->GetInterface(TTimerBase, "main", 1, NULL);
          if(!ITimer) return CleanExit("Can't open timer device Interface");
        }
        else return CleanExit("Can't open timer device");
      }
    }
    else return CleanExit("Can't open timer device. Timer request failed.");
  }
  else return CleanExit("Can't open timer device. Timer msgport failed.");

The system I am running it is an X5000/40 with latest AmigaOS 4.1 FEupd2.

Any idea why this is happening and how I can overcome that? Should I use some other function to get the right time?

Mon, 2021-09-13 20:09

TSK

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Joined: 2011-06-28 02:06

Re: timer device problem with GetSysTime()

I use DOS librarys DateStamp() function to get the date. I'm using GetSysTime only when I'm counting short time periods between two events.

Mon, 2021-09-13 22:21

walkero

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Last seen: 3 months 3 weeks ago

Joined: 2009-05-03 16:54

Re: timer device problem with GetSysTime()

@TSK
Thank you for your reply. To be honest I thought that DateStamp(), because it is part of DOS, would have to do with the date of a file/folder. I will check this out again.

Thank you for your help.

Tue, 2021-09-14 01:24

walkero

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Joined: 2009-05-03 16:54

Re: timer device problem with GetSysTime()

@TSK
Tried the DateStamp(), and when I used DateStampToSecond() I got the same timestamp as with the GetSysTime().
The problem, as Andy (@broadblues) explained it to me, is that Unix epoch starts at 1/1/1970 but Amiga epoch starts at 1/1/1978, and that's the difference. So I had to add that difference to the system timestamp, which is calculated by (365 * 8 + 2(leapyears)) * 24 * 60 * 60.

And that's how I fixed the issue I had.

Thu, 2021-09-16 01:34

(Reply to #4) #5

cwenzel

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Joined: 2021-01-12 07:05

Re: timer device problem with GetSysTime()

If you are using any DOS version past 53.31 (8/2009) then the seconds value is available
as a secondary result from IoErr() and you don't need to supply a datestamp parameter or
convert it back to "AmigaTime".

IDOS->DateStamp(0);
seconds = IDOS->IoErr();

Tue, 2021-10-05 11:25

walkero

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Last seen: 3 months 3 weeks ago

Joined: 2009-05-03 16:54

Re: timer device problem with GetSysTime()

@cwenzel
Oh, I didn't have a clue you can get it that way. What happens on newer versions of DOS?
I will have a look on that as well.

Thank you

Thu, 2021-10-07 02:37

(Reply to #6) #7

cwenzel

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Joined: 2021-01-12 07:05

Re: timer device problem with GetSysTime()

Newer versions continue to have the same functionality.
Result2 (ie; IoErr()) was frequently used to return a second result, not just for error codes.

Secondary returncodes for some functions have existed way back to the 68K days.
I had to make sure these were also correct when I rewrote DOS library.
Quite often, a secondary returncode wasn't even documented, I only found out about it when stuff started crashing and re-discovered it after revisiting the original ASM code to see what was different from my new C-version.

Sometimes I only had to update the documentation to mention argument and returncode quirks, sometimes I needed some additional functionality internally or elsewhere, but it didn't warrant adding a new function to the API just for that, this one is in that catagory.

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