Re: Doubts on mixed threading (FTM -Both ) objects

From:
"buddie84" <buddie84@gmail.com>
Newsgroups:
microsoft.public.vc.atl
Date:
17 Oct 2006 08:50:31 -0700
Message-ID:
<1161100231.578370.216600@b28g2000cwb.googlegroups.com>
Thanks Brian ,
I am novice in this area and trying to understand the concepts ..
Kindly please correct if I am wrong .

1) a COM Object can be obtained from (I am not sure the usage of term
"COM Object" here is correct or not )

a)CComObject<CoClass>::CreateInstance()

-only if we have CoClass implementation source
-we will be getting the CoClass object pointer

If we have 2 Objects of CoClass1 and CoClass2 implemented Interface1
and Interface2
If both are created in the same process and apartment , Is that legal
to implement communications between these classes using member
functions(member of the class but not defined by Interface1 or
interface 2) ?

b) CoCreateInstance
In this case a class will be created and I 'll be getting the requested
interface pointer(pInter) .

Can I cast pInter to CoClass pointer ?

CoClass *pCoClass = CoClass <Some_Cast>pInter;
pCoClass->MemberFunction ()

c) direct pointer from some function
cannot perform any casting, it may be a fully qualified object or it
could be implemented by some other coclass or it could be a proxy to an
object created somewhere

2) we have this class registered as -BOTH in registry

CoClass::Interface1
{
 CoClass::InterfaceMethod1()
 {
  CreateThread(this); //???
 }

 CoClass::Function()
 {
 }

 CoClass::InterfaceMethod2()
 {
 }

Member Variable m_Var;
}

static MyThread(void *p)
 {

 HRESULT hRes = CoInitializeEx(NULL, COINIT_MULTITHREADED);

CoClass *pCoClass= (CoClass*) p;

p->Function(); // {call 1} ?

p->InterfaceMethod2(); // {call 2} ?

p->m_Var; //{call 3} ?

}

where 'Function()' is just a member function which is not the part of
any interface .
and 'InterfaceMethod1 & InterfaceMethod2' is defined in 'Interface1'

For example when a client create the above object on a single thread
apartment

CoInitialize()
Interface1 *pInter =CoCreateInstance(CLSID_CoClass, IID_Interface1)
pInter->InterfaceMethod1();
CoUnInitialize()

In the above scenario {call 1} and {call 2} becomes illegal ... right
?

To resolve this we could pass a marshaled pointer and legally perform
{call 2} , But there might be situations where we need to perform
something like {call 1} and {call3}
(which are not the part of interface)
how could we resolve it ?

3)
When we talked about marshalling ..Interface can be marshalled using
GIT etc ..how can I marshal a CoClass object pointer ?

CoClass::InterfaceMethod1()
 {
 LPVOID pContext=MARSHALL (this); // How????

 CreateThread(pContext);
 }

Thanks

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