how to get UTC time and date from local time?

[CADTenchy]

I'm falling over with this probably easy task.

I'm trying to get from the computer time, a time and date that is in UTC.

Time in format hh:mm (also in hh:mm:ss too)
Date in format yymmdd

I've tried adding ZoneInfo.Bias and ZoneInfo.DaylightBias to my time, but that gets some odd time that counts backwards.

Looking deeper, it seems I can use a function TzSpecificLocalTimeToSystemTime, but I don't get how to use that.
(SystemTime gives UTC all over world, yes?)

Would some kind soul put me out of my misery?


Steve (Delphi 2007 & XP)

 

[roo0047]

Open "Windows SDK" in Delphi Help. (aka "Win32 Developer's Reference")

In the index, browse to "System Time". That page has several links. One is the structure itself, "SYSTEMTIME".

I have a demo app somewhere in my archives that shows all you can do. If I can find it, I'll post it for you. In the mean-time (pun intended), that should keep you busy.

Chicago - Does anybody really know what time it is?
Roo

 

[CADTenchy]

I had found that in help, but I do have trouble interpreting the help into practical code with some of these functions.

I can't seem to see how to translate the info presented

typedef struct _SYSTEMTIME {  WORD wYear;  WORD wMonth;  WORD wDayOfWeek;  WORD wDay;  WORD wHour;  WORD wMinute;  WORD wSecond;  WORD wMilliseconds;
} SYSTEMTIME,  *PSYSTEMTIME;

into something usable like this:

procedure TMainForm.TimeZoneClick(Sender: TObject);
var
  MyTime : TDateTime;
  UTC: TSystemTime;
begin
  MyTime := Time;
  GetSystemTime(UTC);
  with Memo1.Lines do
  begin
    Add('PC time: '+TimeToStr(MyTime));
    Add('UTC: '+IntToStr(UTC.wHour)+':'+IntToStr(UTC.wMinute)+':'+IntToStr(UTC.wSecond));
    Add('Date: '+IntToStr(UTC.wYear)+':'+IntToStr(UTC.wMonth)+':'+IntToStr(UTC.wDay));
  end;
end;

(I found something like the above to adapt to suit me with another go at google today using some different search terms.)

Steve (Delphi 2007 & XP)

 

[roo0047]

I can't seem to see how to translate the info presented... CODE OMITTED ...into something usable like this:... CODE OMITTED

Before explaining, let me ask this: Did your version of Delphi 7 include the RTL source code?

If "yes", right-click on "TSystemTime" in your code and select "Find Declaration".

If not, here is a what you'd see: (from ..\\delphi7\source\rtl\Win\Windows.pas

type
  { System time is represented with the following structure: }
  PSystemTime = ^TSystemTime;
  _SYSTEMTIME = record
    wYear: Word;
    wMonth: Word;
    wDayOfWeek: Word;
    wDay: Word;
    wHour: Word;
    wMinute: Word;
    wSecond: Word;
    wMilliseconds: Word;
  end;
  {$EXTERNALSYM _SYSTEMTIME}
  TSystemTime = _SYSTEMTIME;
  SYSTEMTIME = _SYSTEMTIME;
  {$EXTERNALSYM SYSTEMTIME}

As you can see, Delphi has done it for you. Most all of Windows.pas is a wrapper around the Windows 32 API.

So, your code

  GetSystemTime(UTC);

fills all the UTC record fields as the strucure shows. Use the DateTimeToSystemTime and SystemTimeToDateTime functions to convert between TSystemTime values and TDateTime values.

HTH

Roo
Delphi Rules!