Is the tevent tutorial correct?

[Ralph Böhme]

On Thu, Jan 22, 2015 at 07:37:39AM -0800, Richard Sharpe wrote:
> On Wed, Jan 21, 2015 at 11:07 PM, Ralph Böhme <rb at sernet.de> wrote:
> > Hi Richard
> >
> > On Wed, Jan 21, 2015 at 06:41:28AM -0800, Richard Sharpe wrote:
> >> On Wed, Jan 21, 2015 at 6:38 AM, Andreas Schneider <asn at samba.org> wrote:
> >> > On Tuesday 20 January 2015 20:48:28 Richard Sharpe wrote:
> >> >> Hi folks,
> >> >>
> >> >> I was reading this page https://tevent.samba.org/tevent_data.html
> >> >> prior to taking some people through this tomorrow, and I extracted the
> >> >> code in the tutorial and ran it.
> >> >>
> >> >> The tutorial claims I should see this:
> >> >> ----------
> >> >> a->x: 9
> >> >> b->y: 10
> >> >> c->y: 10
> >> >> ----------
> >> >>
> >> >> However, I see this:
> >> >>
> >> >> ---------------
> >> >> _send
> >> >> a->x: 10
> >> >> b->y: 9
> >> >> c->y: 9
> >> >> Quit
> >> >> ---------------
> >> >
> >> > Might be a typo in the tutorial. Great that someone looks into it.
> >> > Improvements are very welcome!
> >>
> >> I am also trying to understand the intent. The comments suggest that
> >> the three numbers are pulled from different instances of the state
> >> variables but that does not seem to be the case.
> >
> >   Private data can be of 2 types: connected with a request itself or
> >   given as an individual argument to a callback. It is necessary to
> >   differentiate these types, because there is a slightly different
> >   method of data access for each. There are two possibilities how to
> >   access data that is given as an argument directly to a callback.
> >
> > There are two types where one type has two access possibilites, makes
> > for three possibilities.
> >
> > Patch for the wrong exmaple output attached. Please review and push if
> > ok.
> 
> Ahhh, I didn't see your patch when I constructed mine this morning.
> 
> However, I think there is still one thing wrong with the example from
> a pedagogic point of view, which is that by setting up the value of
> the data passed in from main to be the same value as that set in a
> later function it creates confusion is someone's mind, perhaps mine.

Mine too! ;)

> There is also a white-space issue in the top-most call back. See my
> patch from today which is essentially yours with a few more changes.

I saw your patch and had a few issues with it, I'll take another look.

-Ralph

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