Re: Error in documentation?

[David King <amigadave amigadave com>]

On 2012-07-03 12:02, Sarah Hyder <hyder sarah gmail com> wrote:
> Hello,
>
> I'd like to report an error in the GObject Reference Manual. I don't know
> if this is correct as I am a newbie but I think the sample code does not
> show what the description is specifying. Please tell me if I'm wrong
> because this is confusing me.
> Thank you.

A better place to ask for help might be gtk-app-devel-list (as there is 
no dedicated GLib development list) or on #gnome-hackers on 
irc.gnome.org:

https://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
https://live.gnome.org/GnomeIrcChannels

Of course, if you have found a bug, please file it in Bugzilla:

https://bugzilla.gnome.org/

(‘glib’ product, ‘docs’ component would be correct if this was a 
documentation problem)

> In the section  *Instantiable classed types: objects *on line
>
> Every object must define two structures: its class structure and its
> instance structure. All class structures must contain as first member a
> GTypeClass <http://gobject-Type-Information.html#GTypeClass> structure. All
> instance structures must contain as first member a
> GTypeInstance<http://gobject-Type-Information.html#GTypeInstance>
> structure. The declaration of these C types, coming from gtype.h is shown
> below:

The key point here is that the following declarations are of GTypeClass 
and GTypeInstance, not declarations for classes and instances of your 
own objects. Therefore, the documentation is correct. Captions for the 
code listing would help to make this more obvious, of course (if you are 
interested, the documentation is in the file 
‘docs/reference/gobject/tut_gtype.xml’ in the GLib git repository).

http://git.gnome.org/browse/glib

> struct _GTypeClass
> {
>  GType g_type;
> };
> struct _GTypeInstance
> {
>  GTypeClass *g_class;
> };

The next listing in the tutorial explains what the declarations for a 
custom object might look like (which I think is what you were 
expecting), with the paragraphs after that explaining in detail how to 
look up the type of an instance, using the GTypeClass and GTypeInstance 
declarations.

--
http://amigadave.com/