Re: Sharing a smart pointer between threads

From:

"Alexander Nickolov" <agnickolov@mvps.org>

Newsgroups:

microsoft.public.vc.atl

Date:

Tue, 22 Aug 2006 09:25:51 -0700

Message-ID:

<u0FgjegxGHA.5064@TK2MSFTNGP04.phx.gbl>

While this post highlights a bigger issue - how you are using
timers, the problem has nothing to do with GIT. Reading through
the rest of the thread you didn't need GIT in the first place
(something I mentioned briefly in my previous post too...).

--
=====================================
Alexander Nickolov
Microsoft MVP [VC], MCSD
email: agnickolov@mvps.org
MVP VC FAQ: http://www.mvps.org/vcfaq
=====================================

"PaulH" <paul.heil@gmail.com> wrote in message
news:1156189937.877963.260670@m73g2000cwd.googlegroups.com...

Now I have something more like what's below. But, when I go to compile,
the Line with RegisterInterfaceInGlobal() has an error saying m_Obj
isn't static. I can't declare it static without having a lot of other
problems. Is there something I can do to make it happy?

Thanks,
PaulH

1>.\CMyFile.cpp(220) : error C2597: illegal reference to non-static
member 'MyLib::m_Obj'

MyLib::IInterfacePtr m_Obj;
CMyApp::OnTimer()
{
   IGlobalInterfaceTablePtr spGIT(CLSID_StdGlobalInterfaceTable);
   DWORD dwCookie = 0;
   spGIT->RegisterInterfaceInGlobal(m_Obj,
__uuidof(MyLib::IInterface), dwCookie);
   m_dialog->PostMessage(MYWM_UPDATE, static_cast<WPARAM>(dwCookie));
}

CMyDlg::OnUpdateMsg(WPARAM wParam, LPARAM /*lParam*/)
{
   IGlobalInterfaceTablePtr spGIT(CLSID_StdGlobalInterfaceTable);
   MyLib::IInterface *pObj = NULL;
   DWORD dwCookie = static_cast<DWORD>(wParam);
   spGIT->GetInterfaceFromGlobal(dwCookie,
__uuidof(MyLib::IInterface), reinterpret_cast<void**>(&pObj));
   pObj->DoSomething();
   //...
}

Ah, this has PPC2003 support.
Alexander Nickolov wrote:

Unless all your threads belong th ethe MTA, you can't share
the object directly - you need proper marshaling. The perfect
solution for you would be the Global Interface Table (GIT).
It will solve your other problem as well - interface pointer
lifetime. See IGlobalInterfaceTable.

--
=====================================
Alexander Nickolov
Microsoft MVP [VC], MCSD
email: agnickolov@mvps.org
MVP VC FAQ: http://www.mvps.org/vcfaq
=====================================

"PaulH" <paul.heil@gmail.com> wrote in message
news:1156180232.519258.89350@74g2000cwt.googlegroups.com...

I have a COM object smart pointer I'd like to share between threads (as
in the code below). The object works great in the thread it was created
in, but I get an exception when I use it in the thread I'm sending it
to.

How can I successfully share this COM object smart pointer?

Thanks,
PaulH

MyLib::IInterfacePtr m_Obj;
CMyApp::OnTimer()
{
   m_dialog->PostMessage(MYWM_UPDATE,
reinterpret_cast<WPARAM>(&m_Obj));
}

CMyDlg::OnUpdateMsg(WPARAM wParam, LPARAM /*lParam*/)
{
   MyLib::IInterfacePtr pObj = *reinterpret_cast<MyLib::IInterfacePtr
*>(wParam);
   pObj->DoSomething(); //exception here
   //...
}