Confuse about AddRef / Release.

[qur]

Hi I am new in atl com and little confuse about the reference management. Here is the code: typedef stack <CComObject <CLayout> *> LAYOUTSTACK; typedef vector <CComObject <CLayout> *> LAYOUTVECTOR; CComObject * oLayout; LAYOUTSTACK sLayout; sLayout.push (m_opLayout); //where m_opLayout is private memeber oLayout = sLayout.top(); oLayout->AddRef(); //question: this statement is required or not and why? m_vLayoutList.push_back(oLayout); //private member of type LAYOUTVECTOR sLayout.pop(); On general do we need to call AddRef if pointer assignment is done for CComObject <>. Thanks Qur

[Michael Dunn]

qur wrote: do we need to call AddRef if pointer assignment is done for CComObject. CComObject is not a smart pointer class, so any time you create a new reference to the underlying object, you need to AddRef() it. --Mike-- If it doesn't move and it should: WD-40. If it moves and it shouldn't: duct tape. 1ClickPicGrabber - Grab & organize pictures from your favorite web pages, with 1 click! My really out-of-date homepage Sonork-100.19012 Acid_Helm

[qur]

What is the good way to create the coclass object that can take care of reference count.

[Nick Parker]

Michael Dunn wrote: CComObject is not a smart pointer class, so any time you create a new reference to the underlying object, you need to AddRef() it. Ok, not know hardly anything about COM I have a question off this answer. I assume that CComObject is an already wrapped class/object? Otherwise wouldn't you call an AddRef(); function inside your constructor to increment the reference counting? I suppose a more generalized answer to my question would be for me to read more about COM. In due time I suppose. :)

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Nick Parker

You see the Standards change. - Fellow co-worker

[pba_]

ATL abstracts IUnknown implementation in three classes : CComObject / CComAggObject and CComPolyObject - CComObject provides the IUnknown implementation for non-aggregated objects.

[qur]

I have to question: 1- If I chose "yes" in aggregation section of ATL Object Wizard then should a create the coclass object using CComAggObject or CComObject? 2- Do same reference counting rules apply when creating coclass object through CComObject as with interface pointers? Thanx in advance. qur

[pba_]

If you choose "yes" for aggregation then your class can run either standalone or aggregated, so you can use both CComObject or CComAggObject ( depending on your needs). And yes , you will have to take care of the object lifetime, addref-ing and releasing properly any object created by CComObject. However, if you just want to create and use an object inside a function you can use CComObjectStack - it doesn't perform reference counting.