Oracle Forms 6i SendMessage with String

问题:

I am converting my pascal code to PL/SQL for use with Oracle Forms 6i. My pascal code below, works perfectly.

program WebcamTest;
//cswi
//www.delphibasics.info
const
  WM_CAP_DRIVER_CONNECT = 1034;
  WM_CAP_GRAB_FRAME = 1084;
  WM_CAP_SAVEDIB = 1049;
  WM_CAP_DRIVER_DISCONNECT = 1035;

function SendMessageA(hWnd: Integer;
                      Msg: Integer;
                      wParam: Integer;
                      lParam: Integer): Integer;
                      stdcall;
                      external 'user32.dll' name 'SendMessageA';

function capGetDriverDescriptionA(DrvIndex: Cardinal;
                                  Name: PAnsiChar;
                                  NameLen: Integer;
                                  Description: PAnsiChar;
                                  DescLen: Integer) : Boolean;
                                  stdcall;
                                  external 'avicap32.dll' name 'capGetDriverDescriptionA';

function capCreateCaptureWindowA(lpszWindowName: PAnsiChar;
                                 dwStyle: Integer;
                                 x : Integer;
                                 y : Integer;
                                 nWidth : Integer;
                                 nHeight : Integer;
                                 ParentWin: Integer;
                                 nId: Integer): Integer;
                                 stdcall;
                                 external 'avicap32.dll' name 'capCreateCaptureWindowA';

function IntToStr(i: Integer): String;
begin
  Str(i, Result);
end;

var
  WebCamId : Integer;
  CaptureWindow : Integer;
  x : Integer;
  FileName : PAnsiChar;
begin
  WebcamId := 0;
  CaptureWindow := capCreateCaptureWindowA('CaptureWindow', 0, 0, 0, 0, 0, 0, 0);
  if CaptureWindow <> 0 then
  begin
    if SendMessageA(CaptureWindow, WM_CAP_DRIVER_CONNECT, WebCamId, 0) = 1 then
    begin
      for x := 1 to 20 do // Take 20 photos.
      begin
        SendMessageA(CaptureWindow, WM_CAP_GRAB_FRAME, 0, 0);
        FileName := PAnsiChar('C:\Test' + IntToStr(x) + '.bmp');
        SendMessageA(CaptureWindow, WM_CAP_SAVEDIB, 0, LongInt(FileName));
      end;
    end;
    SendMessageA(CaptureWindow, WM_CAP_DRIVER_DISCONNECT, 0, 0);
  end;
end.

I have successfully translated all of the apis using the ora_ffi package.

I am having trouble translating the below line from Pascal to PL/SQL (which saves the captured picture to a specified location identified by FileName).

SendMessageA(CaptureWindow, WM_CAP_SAVEDIB, 0, **LongInt**(FileName));

because I am unsure how to pass the FileName as a PLS_INTEGER (see bold for how I achieve this with pascal) which the SendMessageA definition requires. With pascal I can just cast the FileName to LongInt (does this return a pointer to the FileName? If so, I would like to emulate this casting with PL/SQL).

NOTE: The question is about how to convert Pascal to PL/SQL. The Pascal code works fine.

Any ideas?