Delphi - working with dll's for beginners

I'm a total newbie regarding to DLL. And I don't need to creat them I just need to use one. I've read some tutorials, but they weren't as helpful as I hoped.

Here's the way I started: I've downloaded the SDK which I need to use (ESTOS Tapi Server). I read in the docs and spotted out the DLL which I need to use, which is the ENetSN.dll, and so I开发者_如何学C registered it.

Next I've used the Dependency Walker to take a look at the DLL - and I was wondering because there are only these functions: DllCanUnloadNow, DllGetClassObject, DllRegisterServer and DllUnregisterServer, and these are not the functions mentioned in the docs.

I think I have to call DllGetClassObject to get an object out of the DLL with which I can start to work. Unfortunately the tutorials I found doesn't mentioned how this is done (or I didn't understood it).

There are also 3 exmaples delivered for VB and C++, but I wasn't able to 'translate' them into delphi.

If somebody knows a tutorial where this is explained or could give me a pointer to the right direcetion, I would be very thankful .

The the 3 exported functions indicate that its a COM/ActiveX DLL, If you have registered it with a bit of luck you can get at it via Project->Import Type Library.

Forget about the library being a DLL. Judging from the fact that you had to register the DLL and from the functions it exports, it's a COM/OLE/ActiveX-library. For these you don't care about them being DLLs. Instead you work with them by creating instances of the COM-classes contained therein. Lookup CreateComObject, CreateAutoObject and similar methods. When using the type library importer (see Alex K's post) you might even get a couple of (likely non-visual) components to work with.

You may want to check out Delphi 2010's new feature of delayed loading libraries (DLLs). See http://www.drbob42.com/examines/examinC1.htm for an article and more details.

I wrote a tutorial on Delphi DLLs many years ago, you can find it on DLLs made simple. I don't know if it will be of any use since I haven't worked properly with Delphi for a while, but I can say that it will help to explain the basics to a total beginner. If it is useless, let me know and I'll remove this "answer"...

If you want to call the Dll Procedure or function in your application, then follow this process

procedure TForm1.DllBtnClick(Sender: TObject);

  {Step: 1 To call DLL procedure/function from your program, you first have to 
  declare a type that describes the procedure:}

type
  TSayHello = procedure(pParam: Parameters in the Dll Procedure); 
var
  DLLInstance : THandle;
  SayHello : TSayHello;
begin

  {Step 2: You must load the library}

  DLLInstance := LoadLibrary(`c:\Mydll.dll');
  if DLLInstance = 0 then begin
    MessageDlg(`Unable to load DLL.', mtError, [mbOK], 0);
    Exit;
  end;

  {Step : 3 Get the address of the procedure using GetProcAddress. }

  @SayHello := GetProcAddress(DLLInstance, 'SayHello');
  if @SayHello <> nil then

  {Step: 4 Call your function}

    SayHello(Self)  
  else
    MessageDlg(`Unable to locate procedure.', mtError, [mbOK], 0);

  {Step: 5 Free the Dll}

  FreeLibrary(DLLInstance);
end;

NirSoft's DLL export viewer (http://www.nirsoft.net/utils/dll_export_viewer.html) is capable of listing COM DLL methods.