Re: ATL Basics

From:

"Brian Muth" <bmuth@mvps.org>

Newsgroups:

microsoft.public.vc.atl

Date:

Mon, 22 Oct 2007 09:36:49 -0700

Message-ID:

<#Jxf$mMFIHA.3400@TK2MSFTNGP03.phx.gbl>

There is nothing technically wrong with your code, other than I suggest you set cB to null after the class is deleted, just to make
sure the pointer isn't inadvertently used again.

This really isn't related to ATL whatsoever. ATL code tends to involve the instantiation of COM objects. On the client site, this is
done using CoCreateInstance(), which will return an interface pointer. The interface pointer can be wrapped in a smart pointer, but
not CAutoPtr (usually CComPtr, CComQIPtr, or the interface specific smart pointer generated by the #import directive.

On the server side, sometimes it is useful to instantiate an internal COM object and have a pointer to the class rather than an
interface pointer. CComObject<>::CreateInstance is used for this purpose.

If you are serious about getting into ATL, there is no substitute for a good reference book. Google this newsgroup for "ATL book"
and you will get lots of suggestions.

Brian

"c2" <bleckner@gmail.com> wrote in message news:1193063659.109511.51670@i38g2000prf.googlegroups.com...

Hey all,

I'm trying to write some simple ATL stuff. I've never used ATL before
and it's been several years since I've used C++, so I'm just a little
rusty... :) I have a class that's using a CAutoPtr and CAtlArray.
The class looks something like the code below. Is this the correct
way to use the ATL stuff? My code is working (thankfully), I just
want to make sure I'm things the right way and cleaning everything up
correctly. Thanks in advance!

class SimpleClass
{
public:
   SimpleClass()
   {
       classA *cA = new classA();
       m_pClassA.Attach(cA);

       classB *cB = new classB();
       m_pClassBArray.Add(cB);
   }

   ~SimpleClass()
   {
       for (int i = 0; i < m_pClassBArray.GetCount(); i++)
       {
           classB *cB = m_pClassBArray.GetAt(i);
           delete cB;
       }
       m_pClassBArray.ReleaseAll();

       // m_pClassA is automatically taken care of
   }

private:
   CAutoPtr<classA> m_pClassA;
   CAtlArray<classB *> m_pClassBArray;
}