Re: Who could help me about smart pointer?

From:
"Igor Tandetnik" <itandetnik@mvps.org>
Newsgroups:
microsoft.public.vc.atl
Date:
Sun, 8 Apr 2007 09:48:51 -0400
Message-ID:
<e9Q2QSeeHHA.1220@TK2MSFTNGP03.phx.gbl>
"Lee Tow" <fbjlt@pub3.fz.fj.cn> wrote in message
news:OrGgJxdeHHA.4564@TK2MSFTNGP03.phx.gbl

  There is a method Add and interface ISMath In my compont using
ATL,but when I
compile my client software ,it always display:
error C2039: 'Add' : is not a member of 'CComPtr<struct ISMath>'

   CComPtr<ISMath> *pISMath;


There's no point declaring a pointer to a smart pointer. Make it

CComPtr<ISMath> pISMath;

Everything else below would just work with this change.

      pISMath->Add(1,2,&rst);
cout<<rst<<endl;
CoUninitialize();


Make sure to release the object before calling CoUninitialize - like
this:

pISMath.Release();
CoUninitialize();

Otherwise, CComPtr will call Release automatically when it goes out of
scope, which would be at the closing curly brace of main(), which would
be after CoUninitialize has already been called. It's illegal to make
any COM calls after CoUninitialize, and if you do your program will
likely crash.

Alternatively, organize your code in such a way that CComPtr's scope
ends before CoUninitialize is called. E.g. by introducing an extra pair
of braces, or moving the code between CoInitialize and CoUninitialize
into a separate function.
--
With best wishes,
    Igor Tandetnik

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