Re: Instantiating ComObjects - best practice

"Igor Tandetnik" <>
Sat, 26 Jul 2008 11:28:14 -0400
"Alexander Lamaison" <> wrote in message

On Sat, 26 Jul 2008 10:59:37 -0400, Igor Tandetnik wrote:

Of course, you don't have to "litter" your code with this. Write a
static CMyObject::MakeInstance function that does all this and
returns a properly AddRef'ed interface pointer.

Ok. Thanks. I wasn't sure you were allowed to do this. I'm a little
hazy on what can be called safely in a standard C++ way (i.e. not
through a COM interface) on an ATL object.

An ATL object is a C++ class like any other. There's no black magic
going on.

I've seen people passing 'this' to methods that require an interface
pointer that the object supports, without doing a QueryInterface?

A COM interface is just an abstract C++ class. Your ATL class derives
from it. As usual, you can pass a pointer to derived class wherever a
pointer to base class is needed.

How do you make an object non-creatable?

You don't mention it in IDL, don't derive it from CComCoClass, don't
list it in object map (omit OBJECT_ENTRY[_AUTO] for it) and don't
register it (remove all references to it, if any, from .RGS files).

In other words, all objects are non-creatable until you _do_ all of the
above to make one creatable.
With best wishes,
    Igor Tandetnik

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