Re: passing this object

From:
David Wilkinson <no-reply@effisols.com>
Newsgroups:
microsoft.public.vc.language
Date:
Thu, 27 Nov 2008 06:19:52 -0500
Message-ID:
<OnzAQIIUJHA.5860@TK2MSFTNGP02.phx.gbl>
Jung, William wrote:

I would like to pass "this" object to a constructor of socket class -
Sock which extends CSocketComm.

Once the socket class processed the data, the socket class use the
reference of CVirtualScreen (this object) - screen.setMessage function
to pass back the message to CVirtualScreen.

Is the following a correct syntax of implementing it?

should I involve reference / pointer in this case?

Please advice the incorrect area of the following code.

===================
class CVirtualScreen
{
public:
    CVirtualScreen();
    ~CVirtualScreen();
    Sock *sock;
}
===================
CVirtualScreen::CVirtualScreen()
{
    // QUESTION ///////////////////////////
    // IS IT CORRECT WAY OF PASSING
    // THIS OBJECT TO SOCKET CLASS??
    // SHOULD I USE & REFERENCE??
    // SHOULD I USE POINTER??
    sock = new Sock(this);
}

// function must take std::string as parameter
CVirtualScreen::setMessage( std::string message )
{
    //setMessage to queue
}
===================
class Sock : public CSocketComm
{
public:
Sock(CVirtualScreen screen);
~Sock();

// QUESTION ///////////////////////////
// DO I DECLARE REFERENCE TO CVirtuaqlScreen LIKE THIS WAY??
CVirtuaqlScreen screen;

virtual void OnDataReceived(const LPBYTE lpBuffer, DWORD dwCount);
bool StartServer();

};
===================
Sock::Sock(CVirtualScreen screen)
{
    // QUESTION ///////////////////////////
    // CAN I SET REFERENCE TO CVirtualScreen LIKE THIS??
    // SHOULD I USE POINTER??
    screenObject = screen
    StartServer();
}
Sock::~Sock()
{
    StopComm();
}
void Sock::OnDataReceived(const LPBYTE lpBuffer, DWORD dwCount)
{
    // do some stuff and output the std::string object
    std::string message = ... etc
    // QUESTION ///////////////////////////
    // ONCE SOCKET PROCESSED THE MESSAGE AND EXTRACT THE DATA
    // SOCKET WILL PASS THE MESSAGE BACK TO CVirtualScreen TO
    // INSERT MESSAGE INTO A MESSAGE QUEUE
    // IS THE FOLLOWING COORECT SYNTAX TO PASS MESSAGE BACK TO
    // CVirtualScreen CLASS??
    screen.setMessage ( message );
}


William:

A question like this can most easily be answered by trying to compile your code.
  Your code will generate a number of errors.

You should use a pointer member variable CVirtualScreen* in your Sock class, and
pass your "this" object to it as a CVirtualScreen*.

I would advise you to get a much better grasp of C++ before you try to use it
for socket programming.

--
David Wilkinson
Visual C++ MVP

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