Re: gobject docs

[Owen Taylor <otaylor redhat com>]

On Tue, 2003-10-14 at 19:01, Matthias Clasen wrote:

> > ===
> > The intro needs to go into more detail about how C marshallers are
> > used in GObject and also link to glib-genmarshal.
> > 
> > I don't think there is sufficient information here to really explain
> > when/why you would call g_closure_set_marshal() yourself when writing
> > a C library. I think a full example of a callback done with a closure
> > would be a good idea, especially to show things like checking 
> > if (G_CLOSURE_NEEDS_MARSHAL (closure)) {} before setting your own
> > marshaller.
> > 
> 
> ...except for this, as I'm not sure I understand it. Can you actually
> use a closure without calling g_closure_set_marshal() on it ? I notice
> that g_closure_invoke() has g_return_if_fail (closure->marshal ||
> closure->meta_marshal); but the meta marshallers in gclosure.c all call
> closure->marshal after doing their thing, so you end up needing
> closure->marshal even if you have a meta marshaller.

The point is that if the closure already has a marshaller - say, because
it's a language-binding closure, then you don't want to override it.
with a C-function marshaller.

> Could you point me to a "full example of a callback done with a 
> closure" ?

You can look at gobject/gsourceclosure.c, though that has some 
non-essential complications related to the the fact that we are
installing closures for callbacks in libglib.

Regards,
						Owen