Delphi 2009 & C Dll

I have a dll with this function

extern "C"{
__declspec(dllexport)double GetValue(char *funzione, double incognita);
}

This is my delphi code

procedure TfrmMain.TracciaAssi();
var
  str: string;
  addr: Pointer;
  res: Double;
  val: Double;
  proc: function(funzione: Pointer; incognita: Double):
    Double  cdecl  {$IFDEF WIN32} stdcall {$ENDIF};
  DLLHandle: THandle;
begin
  with desktop do
  begin
    Canvas.MoveTo(0, round(frmMain.Height/ 2) - 25);
    Canvas.LineTo(frmMain.Width, round(frmMain.Height/ 2) - 25);

    Canvas.MoveTo(round(frmMain.Width/ 2), 0);
    Canvas.LineTo(round(frmMain.Width/ 2), frmMain.Height);

    str:= 'sinx';
    val:= 1;
    res:=0;
    addr:= @str;
    DLLHandle:= LoadLibrary('RpNotation.dll');

    if DLLHandle <> 0 then
    begin
      @proc:= GetProcAddress(DLLHandle, 'GetValue');
      if Assigned(proc) then
      begin
        res:= proc(addr,val);
      end
      else
        MessageBox(0,'Errore','Errore',0);
    end;

  end;
end;

In this way I have an access error
I see that 'funzione' get a "s" value instead "sinx"

How can I do?

Replies

• Re: Delphi 2009 & C Dll posted by Remy Lebeau on Sat, 2 May 2009