[Qt-interest] How to know whether an instance of a COm object isalready running

[Malyushytsky, Alex]

I have not being using COM for like 10 years,
so my knowledge might be outdated and you still probably should look for help in COM related lists,
but here is a few comments:

- results obtained with calling com related functions has to be checked with if(SUCCEEDED( res ))
That is the only way to obtain reliable information what happened to your call.

- to insure that you deal with the same object (within the same application) you can simply keep - not releasing
pointer to one of the interfaces, for example to IUnknown.

This should keep that object loaded and you can use such pointer late, for example to obtain different interfaces.

Hope this helps,
  Alex



From: qt-interest-bounces at trolltech.com [mailto:qt-interest-bounces at trolltech.com] On Behalf Of Santhosh Y
Sent: Thursday, July 08, 2010 5:06 AM
To: Scott Aron Bloom
Cc: qt-interest at trolltech.com
Subject: Re: [Qt-interest] How to know whether an instance of a COm object isalready running

Hi Scott,

Yeah I understand it is not a Qt issue.
But I am struck here and I thought if some one helps me out who has a knowledge on this ,  it would be great.

Thanks.

On 7/8/2010 5:33 PM, Scott Aron Bloom wrote:
Ask a COM list.. this has nothing to do with Qt..   Just because you are using QAxObject doesn’t make it a Qt issue

From: qt-interest-bounces at trolltech.com [mailto:qt-interest-bounces at trolltech.com] On Behalf Of Santhosh Y
Sent: Thursday, July 08, 2010 4:58 AM
To: qt-interest at trolltech.com
Subject: [Qt-interest] How to know whether an instance of a COm object isalready running

Hi,

How  to know, whether an instance of a COM object is already existing/running?

In following main(), I am reading a factory instance. Using Factory instance I am creating an instance of the COM object for invoking few methods on it.
I would like to know, when an instance of COM object is already existing/running, I should not be creating a one more instance instead I should use the same one.
How to ensure this?

int main ()
{
    IClassFactory* factory = 0;
    // Getting the factory
    HRESULT res = CoGetClassObject(QUuid("{084EF014-6C9B-4d50-8756-263CDAC6DE4B}"), CLSCTX_ALL,  0, IID_IClassFactory,  (void**)&factory);

    if (factory) {

        // I would like to know here whether an instance is already present/running on machine
        // If YES, I should get that instance for invoking few methods on it. Else I should be doing this.
        // creating instance
        res = factory->CreateInstance(0, IID_IUnknown, (void**)&ptr);

        //Creating a QAxObject that wraps the COM object referenced by IUnknown.
        QAxObject* comObj= new QAxObject (ptr);
        comObj->dynamicCall("setPath", "C:\\cygwin\\home\\JNK\\aera2GUI\\bin_dbg\\aera2gui.exe");
        comObj->property("renewIAState").toInt();
    }
}

Please help me in this regard.

Regards,


--
----------------------------------------------------
Y Santhosh Kumar -
Senior Software Engineer,
SoftJin Technologies Pvt Ltd,
www.softjin.com
----------------------------------------------------


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--
----------------------------------------------------
Y Santhosh Kumar -
Senior Software Engineer,
SoftJin Technologies Pvt Ltd,
www.softjin.com
----------------------------------------------------


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