Re: Returning an error from QTVOPNVT

[Bruce Vining <bvining@xxxxxxxxxxxxxxx>]

How are you defining and initializing the error code parameter? If all
you're doing, to get the program to crash, is passing in a non-zero value
then I suspect the API is overwriting your program storage while returning
error related information -- meaning that BytesProvided does not reflect
your actual allocation of the structure.

Bruce

On Tue, Nov 1, 2011 at 5:59 PM, Ryan Downing <rdowning@xxxxxxxxxxxxxxxx>wrote:

> Hey folks,
>
> I'm a little new to this iSeries thing, and I have a problem I was
> hoping someone could help me with...
>
> I'm opening a virtual terminal session to an iSeries using the IBM API
> QTVOPNVT in a C++ program using all three of the optional parameter
> groups.
>
> The current issue under test is what happens if the data queue
> mentioned in the function call (6th parm) is missing.  The program
> works correctly in other circumstances with both exception handling
> and error struct passing.
>
> Using the pragma style exception handling, it correctly returns a
> CPF9801 in the caught error.  Passing in a Qus_EC struct with
> Bytes_Provided set to a non-zero value crashes the program.  Looking
> in the IBM documentation for the API call, CPF9801 (or, for that
> matter, any sort of "data queue not found" type error) doesn't appear
> in the expected errors list, so I'm thinking it might not be able to
> handle this eventuality.
>
> My shop has strong feelings towards using only return value error
> handling, so I'd prefer not to use the exception method, but the only
> way I can think of to get around it right now is to first do another
> API call to test existence of the data queue and I'd like to avoid the
> performance hit.
>
> Does anyone know if there's a way to get the best of both worlds?
> Maybe I'm doing something wrong on the call...?  Even confirmation
> that I can't get a return of this value would be great.
>
> Definition of API:
>
>
> #pragma map(OpenVT,"QTVOPNVT")
> extern "OS" void  OpenVT(
>                                char *,
>                                char *,
>                                int,
>                                int,
>                                int,
>                                char *,          /* Passing in a Queue here
> which does not exist */
>                                char *,
>                                int,
>                                void *,
>                                char *,
>                                char *,
>                                char *,
>                                int);
>
>
> Cheers,
>  Ryan
> --
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