Use the ServerExceptionHandler .. This is called when ever a exception
propagates out of a method marked as SafeCall.
Remember all COM and hence SAFECALL's calls are actually function calls that
return HRESULT, so exceptions do not get propagated out of a COM object,
they are caught by the try except block around the method call and changed
into HRESULT code to be passed back to the caller.
All our COM objects implement these and log any exceptions caught in the NT
event log.
eg
procedure TMyComObject.AfterConstruction;
begin
inherited;
ServerExceptionHandler := TMyExceptionHandler.Create;
end;
procedure TMyComObject.BeforeDestruction;
begin
ServerExceptionHandler := nil;
inherited;
end;
TMyExceptionHandler = class(TInterfacedObject, IServerExceptionHandler)
procedure OnException(
const ServerClass, ExceptionClass, ErrorMessage: WideString;
ExceptAddr: Integer; const ErrorIID, ProgID: WideString;
var Handled: Integer; var Result: HResult);
end;
procedure TMyExceptionHandler.OnException(const ServerClass, ExceptionClass,
ErrorMessage: WideString; ExceptAddr: Integer; const ErrorIID,
ProgID: WideString; var Handled: Integer; var Result: HResult);
begin
//Handle the exception however you want to ...
// Do not pass the message onto the OS's COM subsystem - however you can
if you want to.
Handled := Integer( True );
end;
> -----Original Message-----
> From: Tom Munro Glass [SMTP:[EMAIL PROTECTED]]
> Sent: Tuesday, 21 December 1999 04:07
> To: Multiple recipients of list delphi
> Subject: [DUG]: Threads and COM
>
> Can someone please give me some tips for exception handling in a COM-based
> application?
>
> The application uses a number of in-process and out-of-process COM
> servers,
> and exceptions are occurring but the Application.OnException event is not
> getting called. The result is that the application displays an error
> message
> and then terminates without me having a chance of dealing with the source
> of
> the exception.
>
> I see that the application has several threads (I'm not creating any
> threads
> directly), so I assume that these are being created by COM. I suspect that
> the exceptions are occurring in one of these threads, but how do I go
> about
> catching these?
>
> ==================================================================
>
> Tom Munro Glass
>
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