Re: Pass CComPrt to and from function

From:
brosembob@yahoo.com
Newsgroups:
microsoft.public.vc.atl
Date:
12 Sep 2006 10:06:53 -0700
Message-ID:
<1158080812.994272.270170@i42g2000cwa.googlegroups.com>
Hi Igor,
Thanks for your reply. If I add more details of my code as follows,
would it still be ok?

//************ Header file *********
class CLRHost
{
public:
        CLRHost();
        virtual ~CLRHost();
        CComPtr<ICorRuntimeHost> GetCComPtr(void);
        SetComPtr(CComPtr<ICorRuntimeHost>);
private:
        CComPtr<ICorRuntimeHost> rntHost;
        CComPtr<_AppDomain> spDefAppDomain;
        CComPtr<_ObjectHandle> spObjectHandle;
        CComPtr<IDispatch> pDisp;
};

//************* Class implementation (.Cpp file) ***
CComPtr<ICorRuntimeHost> CLRHost::GetCComPtr(void)
{
        return rntHost;
}
void CLRHost::SetCComPtr(CComPtr<ICorRuntimeHost> _rntHost)
{
        rntHost = _rntHost;
}
....
....
....
//************** Call to the clrHost object to set/get CComPtr ****
CLRHost* clrHost;
int CreateCLRHost()
{
        clrHost = new clrHost();

        CComPtr<ICorRuntimeHost> spRuntimeHost;

        HRESULT hr = CorBindToRuntimeEx( NULL,
L"wks", TARTUP_LOADER_OPTIMIZATION_SINGLE_DOMAIN |
                STARTUP_CONCURRENT_GC,
                CLSID_CorRuntimeHost,
                IID_ICorRuntimeHost,
    (void**)&spRuntimeHost //pointer to CLR
        );

        clrHost.SetCComPtr(spRuntimeHost);
}

int StartCLRHost()
{
        CComPtr<ICorRuntimeHost> host;
        host = clrHost.GetCComPtr();
        host.Start;
        ...
        ...
}

Here in CreateCLRHost function I create a spRuntimeHost object Then I
pass it to the clrHost class and using = operator make a local copy of
it.
1. Does = operator creates a true copy of the spRuntimeHost object or
adds reference to the same one that I passed in?
2. Is spRuntimeHost object destroyed after I leave the CreateCLRHost
function?
3. If CreateCLRHost function gets called multiple times and many
clrHost objects created, I need each object to have its own
spRuntimeHost instance created. Is it true with this scenario?

Thanks,
Bob

Igor Tandetnik wrote:

brosembob@yahoo.com wrote:

I'm trying to use CComPtr class. What's the right way to pass to and
return from function CComPrt object? Following is the snippet of code
that I have so far. It compiles and seems to do what I need, but I'm
not sure if it's Ok to pass entire class back and forth.


It's Ok. Your code looks good to me.
--
With best wishes,
    Igor Tandetnik

With sufficient thrust, pigs fly just fine. However, this is not
necessarily a good idea. It is hard to be sure where they are going to
land, and it could be dangerous sitting under them as they fly
overhead. -- RFC 1925

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