How to format a Unix timestamp in Delphi?

I have

var timestamp: Longint;  
timestamp := Round((Now() - 25569.0 {Unix start date in D开发者_高级运维elphi terms} ) * 86400);

which I am using as a primary key in some MySql stuff.

But I would also like to format the date/time, like PHP's date() function does.

Does anyone have a code snippet or URL?

You are looking for

function DateTimeToUnix(const AValue: TDateTime): Int64;

and

function UnixToDateTime(const AValue: Int64): TDateTime;

functions from DateUtils.pas

TDateTime value can be formatted by FormatDateTime function

This is much faster

// 4x faster than dateutils version
function UNIXTimeToDateTimeFAST(UnixTime: LongWord): TDateTime;
begin
Result := (UnixTime / 86400) + 25569;
end;

// 10x faster than dateutils version
function DateTimeToUNIXTimeFAST(DelphiTime : TDateTime): LongWord;
begin
Result := Round((DelphiTime - 25569) * 86400);
end;

I would use DateTimeToUnix, as suggested by @kludg.

function DateTimeToUnix(const AValue: TDateTime): Int64;

In case you want the current Unix timestamp in milliseconds format, you can implement the following function:

function UNIXTimeInMilliseconds: Int64;
var
  DateTime: TDateTime;
  SystemTime: TSystemTime;
begin
  GetSystemTime(SystemTime);
  DateTime := SysUtils.EncodeDate(SystemTime.wYear, SystemTime.wMonth, SystemTime.wDay) +
        SysUtils.EncodeTime(SystemTime.wHour, SystemTime.wMinute, SystemTime.wSecond, SystemTime.wMilliseconds);
  Result := DateUtils.MilliSecondsBetween(DateTime, UnixDateDelta);
end;