Question

Please let me know How to get current Unix timestamp in Inno Setup?

Answer 1

The easiest way is to use the time() function from the C runtime library, which has the following return value:

Return the time as seconds elapsed since midnight, January 1, 1970, or
-1 in the case of an error.

which is exactly what the unix timestamp is.

Now it’s a simple matter of importing that function into Inno Setup scripting. Since the scripting environment doesn’t know pointers the parameter (which luckily need not point to a valid buffer, see the linked documentation) is given as integer and you must pass a 0 for it:

function Time(ATimerPtr: integer): integer; external '[e-mail] cdecl';

function InitializeSetup(): Boolean;
begin
  MsgBox(Format('unix timestamp: %d', [Time(0)]), mbInformation, MB_OK);
end;