Code:

{ .... }

type

VA_FN = function(const par1, par2{, ...}: Pointer): Boolean;

                  cdecl varargs;

{ .... }

//

// varargs without "external" keyword

//

function fn(const par1, par2{, ...}: Pointer): Boolean; cdecl;

var

last_arg: Pointer absolute par2;

ptr_args: array[0..MAXLONG shr 2] of Pointer absolute last_arg;

dw_args: array[0..MAXLONG shr 2] of Cardinal absolute last_arg;

s_args: array[0..MAXLONG shr 2] of PChar absolute last_arg;

w_args: array[0..MAXLONG shr 2] of WideString absolute last_arg;

begin

// ptr_args[1] is first optional argument

Result := (ptr_args[1] {par3} = Pointer(1)) and

   (dw_args[2] {par4} = 2) and

   (string(ptr_args[3]) = 'CHAR') and

   (w_args[4] = 'WCHAR');

end;

procedure test_fn;

begin

// VA_FN typecast

VA_FN(@fn)({par1}nil, {par2}nil, {par3}Pointer(1), {par4}2, {par5}'CHAR',

   {par6}WideString('WCHAR'));

end;