1  |   Order by index

May 22, 2006, 10:11am

Until yesterday, I was blissfully unaware of a number of issues I had with
using the SDK under .NET (C#). Some VERY shy exceptions keeping themselves
out of sight (System.Timers.Timer! GRRR!) meant I was missing some real
problems with interfacing with the SDK. I think this list is going to grow,
so I'll start with the three I've attached below.

This is using .NET 1.1 (but the same happens in 2.0) and SDK Build 41. If
anyone has experienced these before and/or has any constructive comments,
I'd be grateful.

Many thanks,

Grims.

**********
*** C# Callback Delegate
**********
I have SDK callbacks being installed though the use of a delegate, as
follows:

public delegate void SDKCallbackHandler(int ReturnCode);

This works great until the end of the delegate processing, when the
application kicks out a null reference exception from within aw_wait(). It
would seem not to be a GC'd delegate - .NET has a specific exception for
GC'd delegates and all the delegate instances are static and within context.
I get no such problems with the event delegates.

**********
*** AW_CALLBACK_LOGIN/aw_login Return Code
**********
Possibly related to the delegate issue above (only because its a callback),
but when I install the AW_CALLBACK_LOGIN callback, aw_login() returns a 439
(No Connection). If I don't install the callback, it logs in fine.


**********
*** aw_cell_next Return Code
**********
This one is annoying. As I've done before in other languages, I have a query
facility for a single cell using the aw_cell_next with a forced value for
AW_CELL_ITERATOR. Generally this works fine, with the AW_EVENT_CELL_BEGIN,
AW_EVENT_CELL_OBJECT and AW_EVENT_CELL_END events all being delivered and
setting the attributes that would be expected. However, the return code for
the aw_cell_next call is always 74 (No Such Cell). Its not my calculation
for AW_CELL_ITERATOR, because I've tried setting it to zero (as per docs)
and the same happens - the events are fired but it returns 74 and
AW_CELL_ITERATOR is not incremented.

May 22, 2006, 2:02pm

[View Quote] <snip>

> **********
> *** aw_cell_next Return Code
> **********
> This one is annoying. As I've done before in other languages, I have a query
> facility for a single cell using the aw_cell_next with a forced value for
> AW_CELL_ITERATOR. Generally this works fine, with the AW_EVENT_CELL_BEGIN,
> AW_EVENT_CELL_OBJECT and AW_EVENT_CELL_END events all being delivered and
> setting the attributes that would be expected. However, the return code for
> the aw_cell_next call is always 74 (No Such Cell). Its not my calculation
> for AW_CELL_ITERATOR, because I've tried setting it to zero (as per docs)
> and the same happens - the events are fired but it returns 74 and
> AW_CELL_ITERATOR is not incremented.
>
>

This error exists only when you are trying to do it in AW. All other worlds seems fine.
AW uses multiple ctree databases due to the sheer size and the iterator just don't work there with the "combine" feature.
Set AW_COMBINE to false and it will work (of course it will be a cell by cell query).

--
Andras
"It's MY computer" (tm Steve Gibson)

May 22, 2006, 4:38pm

Thanks Andras. Yes it was in AW, but the value of AW_CELL_COMBINE doesn't
appear to make a difference - I get a 74 in either case. This isn't a major
issue if its an AW only thing. I would assume that there won't be another
world like AW with this complication, so for now I can work around it until
I run it somewhere else.

Thanks for the info.

Grims.

[View Quote]

May 23, 2006, 6:41am

I hope this doesn't turn into a thread of me talking to myself, but I've
found ONE solution that seems to solve the null reference exception. Having
said that, its far from elegant (actually its a mess!) and I don't really
want to use it, but it does confirm the problem - calling convention
(although if that's the case then I'm surprised no-one else has hit it
unless other .NET users are going through COM).

Back in the days when I was using VB6, I created a new aw.dll from
aw_static.lib and used this directly from VB6 without going through COM. I
think that would probably be the best way to address this as well (its a
shame I don't have the code anymore!). Its nothing difficult, just an amount
of effort to put a prototype together. Once I've confirmed it works, if
there's a demand for it from others then I'll redo it a little more neatly
and tout it about.

Again, any comments welcome.

Grims.


[View Quote]

May 24, 2006, 6:12am

The new DLL worked great - it can be called directly (and safely) from .NET
with appropriate prototypes. It may be a while before I get a chance to
finish it and tart it up (or it may not), but I'll probably wait until the
final 4.1 SDK is available so that it can support that release before I
publish it.

Grims

[View Quote] > Back in the days when I was using VB6, I created a new aw.dll from
> aw_static.lib and used this directly from VB6 without going through COM.

May 24, 2006, 6:15am

This one is is still a problem for me. Does anyone else suffer from this on
Build 41 (on any platform)?

Grims

[View Quote]

May 25, 2006, 5:54am

Last post on this. .NET 2.0 handles the calling convention issue with
callbacks by using an attribute on the delegate, so there's no need to worry
about this afterall (unless you're like me and use .NET 1.1).

1  |   Order by index