Given a function that looks like this:

HRESULT MyServer::GetSomeData(DWORD dwNumItems, VARIANT * ppvData);

...where dwNumItems is the number of VARIANTS in the array pointed to by
ppvData, ie, the caller allocates the array for the data to be returned.

Question:
Should the server initialize the each of the VARIANTs in the array by
calling VariantInit?

> -----Original Message-----
> From: Vagish Kalligudd [SMTP:vagish.kalliguddCELSTREAM.COM]
> Sent: Friday, February 15, 2002 8:26 AM
> To: DCOMDISCUSS.MICROSOFT.COM
> Subject: Re: RPC Exception, Subsequent Calls Hang
>
> Your error code 0x80010105 indicates that the server is throwing a C++
> exception. You can enable exception handling. If you are using ATL you can
> use ATLTRY to bracket all code that could possibly throw exceptions. If
> you
> want to catch memory access violations using catch(...) enable /EHa on
> Visual C++.
>
>
> Quote from MSDN
> COM and C++ Exceptions
> --------------------------------------------------------------------------
> --
> ----
> COM will not propagate a C++ exception from the callee to the caller,
> even
> when both the caller and the callee are written in C++. This catches some
> COM newcomers off guard, but it should be no surprise if you recall that
> COM
> is language-independent. COM boundaries are language boundaries. After
> all,
> if the caller is written in C and the callee is written in C++, what would
> COM do with the C++ exception? If your code throws an exception, the
> caller
> will see a failure with an HRESULT of 0x80010105 (RPC_E_SERVERFAULT).
> Interestingly enough, this is the same error the caller sees if the callee
> attempts an illegal memory access. In both cases, the COM runtime isolates
> the caller of the object from runtime errors inside the object and
> presents
> them as server errors.
>
>
> -----Original Message-----
> From: Mark Jordan [mailto:mark.jordanEXELONCORP.COM]
> Sent: Friday, February 15, 2002 7:43 PM
> To: DCOMDISCUSS.MICROSOFT.COM
> Subject: RPC Exception, Subsequent Calls Hang
>
>
> Hey Folks,
>
> I have a DCOM Server (OPC) that provides data to many clients on many
> different machines.
>
> I have encountered a random bug that is hard to track down. As near as I
> can tell, the following occurs:
>
> 1) All clients are working fine for a while (could be days or weeks).
> 2) Suddenly, one client will encounter 0x80010105 (not sure where, users
> aren't much help).
> 3) From then on, all other attempts to connect to the server hang. It
> appears that CoCreateInstanceEx succeeded and QueryInterface for various
> Interface pointers succeeds, but the first function call attempted hangs
> indefinitely.
>
> I don't know enough about the inner-workings of DCOM to know where to
> look.
>
> I'm willing to bet there is some bad code in the DCOM server somewhere
> that
> every once in a while throws an exception (in my experience, random
> indetermine bugs are memory related). I am rigorously looking through the
> code for potential bugs. I am asking this group for two things.
>
> (1) What are some common pitfalls people have seen with memory in DCOM
> servers? Aside from standard C++ coding hazards...I'm talking about
> CoTaskMemAlloc and the like.
> (2) If someone could give a clear description of what is actually getting
> hung up (I'm guessing it's marshalling code or proxy/stub code?) and
> causing
> problems, I'd appreciate it. I'm asking for this in general terms.
> Clearly, no one can diagnose my problem from afar.
>
> Thanks in advance for any help you can all provide.
>
> Mark Jordan
> mailto:mark.jordanexeloncorp.com
>
> ----------------------------------------------------------------
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