Re: Raise Errors from non-coclasses

From:
"Igor Tandetnik" <itandetnik@mvps.org>
Newsgroups:
microsoft.public.vc.atl
Date:
Tue, 4 May 2010 10:43:21 -0400
Message-ID:
<evz0lg56KHA.3184@TK2MSFTNGP05.phx.gbl>
Barzo <dbarzo@gmail.com> wrote:

On 4 Mag, 13:43, "Igor Tandetnik" <itandet...@mvps.org> wrote:

Barzo wrote:

Ok, now I have to raise a COM error from the non-coclass
implementation file.

 
AtlReportError, pass GUID_NULL for CLSID parameter.

 
Like show here:
http://support.microsoft.com/?scid=kb%3Ben-us%3B827994&x=11&y=10
 
I use this line to raise an "Invalid Index" to a VB6 client:
return AtlReportError(GUID_NULL, (LPCOLESTR)0, IID_IAudioRecorder,
DISP_E_BADINDEX);
 
But the VB6 Err object shows:
 
Err.Number = -2147352565 (Which is correctly 0x8002000B =
DISP_E_BADINDEX)
Err.Description = Unknown Error


Hmm. The way AtlReportError (or, to be precise, AtlSetErrorInfo) is =
written, it never sets the description to NULL. If you try to pass NULL =
to it (as you did), it generates a default string "Unknown Error" (as =
you observed).

I suppose you'll have to write your own helper function similar to =
AtlSetErrorInfo. You can look at its implementation in atlcom.h
--
With best wishes,
    Igor Tandetnik

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