[fpc-devel] Convert time to GMT

[Graeme Geldenhuys]

On 8/14/08, amir <amir at aavani.net> wrote:
>  I want to have the date/time of my computer for GMT. As I searched the
> rtl.pdf, I found out that there are some functions
>  in OLDLinux unit which return the current time for GMT (not local
> timezone). I wonder if they can be used on Windows (It said
>  that those functions return the current kernel time which is in GMT).
>
>  I also found two functions for reading the local timezone but they are
> located in Unix and OLDUnix units. Do they have an implementation
>  on Windows?


With complements from the tiOPF project. ;-)


{$IFDEF MSWINDOWS}
function tiGMTOffset: TDateTime;
var
  TZI: TTimeZoneInformation;
begin
  Result := 0; // Removes 'return value might be undefined' warning.
  case GetTimeZoneInformation(TZI) of
    TIME_ZONE_ID_STANDARD: Result := (TZI.Bias + TZI.StandardBias) *
cdtOneMinute;
    TIME_ZONE_ID_DAYLIGHT: Result := (TZI.Bias + TZI.DaylightBias) *
cdtOneMinute;
    TIME_ZONE_ID_UNKNOWN: Result := TZI.Bias * cdtOneMinute;
  else
    RaiseLastWin32Error;
  end;
end;

function tiLocalTimeToGMT(const ALocalTime: TDateTime): TDateTime;
begin
  Result := ALocalTime + tiGMTOffset;
end;

function tiGMTToLocalTime(const AGMTTime: TDateTime): TDateTime;
begin
  Result := AGMTTime - tiGMTOffset;
end;
{$ENDIF}



Regards,
  - Graeme -


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