Re: Callbacks (Was: Some activity and a new LibOfx)

All right, I've committed the changes. The changes are significant, so here's 
a brief introduction. 

The CallbackRegistry structure has been expanded to include a void pointer for 
each callback function. The ofx_prep_cb function has also been expanded to 
include arguments for setting that void *, but these arguments can be null if 
desired. When the callback is executed, the void * from the registry is sent 
as the second argument. This allows a user to pass arbitrary information to 
the recipient of the callback, as well as the ofx data that was previously 
sent.

I also made the suggested changes below. I named the arguments XXX_data where 
XXX is status, security, et. al. I hope that's okay.

ry


On Sunday 18 January 2004 17:50, Benoit Grégoire wrote:
> On Sunday 18 January 2004 10:35, ryan p bobko wrote:
> > Hi Everyone,
> > I'm not sure what the procedure is for applying patches, so I thought I'd
> > give a quick heads-up on the work I've been doing on the library before
> > committing anything. I've included a patch in this email that extends the
> > callback registry a bit, but it also changes the prototypes of the
> > various callback functions.
>
> As there is no CVS commit mailing list (anyone know how to set one up an
> sourceforge?), the "procedure" is to write good Changelog entries (not just
> in CVS, in the ChangeLog file also) and to send a email here if the change
> is significant.  A pach isn't needed unless the focus of your message if
> for people to review the changes.
>
> > Quick background: I'm a C++ developer, and I'd like to be able to use
> > libOFX in a class I've built with as little reliance on global variables
> > as possible. I just want to be able to assign arbitrary callbacks to the
> > events that get thrown.
> >
> > To accomplish this, I added the callback registry, but that really only
> > got me halfway there. I also need to be able to specify the instance of
> > my object that can handle the callback, so I added a void * for each
> > function pointer in the registry, and changed the prototypes of the
> > functions to accept a void * in addition to the Ofx data structure they
> > each receive. I changed the ofx_container_* files to pass the void * from
> > the registry to the callback as the first argument. This way, not only
> > can the callbacks handle data, they can use it to change particular
> > structures/classes/other functions.
> >
> > If there are no objections, I'd like to commit these changes. I'm open to
> > other ideas on accomplishing my goal, too.
>
> Your approach is correct, we definitely need a void * pointer to be passed
> to the callback for it to be usefull.  However I do have a few stylistic
> nitpicks:
>
> 1- As the parameter is "optionnal" (can be NULL), I think it should be the
> last parameter, not the first.  But that's not very important.
> 2- You named it o (presumably for object).  That's inacurate and not very
> descriptive.  Is suggest naming it user_data (like in gnome), as it could
> be a pointer to anything (a structure, a function, an object, a GUI
> element, whatever).
> 3- Please pass NULL, not 0 when it isn't used.
>
> Again, thanks for your work!

-- 
In theory, there is no difference between theory and practice.
In practice, there is. 



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