# Binding questions **URL:** \ **Category:** Ruby-Gnome 2\ **Created:** [October 17, 2008, 3:40pm UTC](https://www.ruby-forum.com/t/binding-questions/151162 "2008-10-17T15:40:14Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![Andrew\_SSTownley](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/d07c76/32.png) [@Andrew\_SSTownley](https://www.ruby-forum.com/u/Andrew_SSTownley)\ **Post date:** [October 17, 2008, 3:40pm UTC](https://www.ruby-forum.com/t/binding-questions/151162/1 "2008-10-17T15:40:14Z")
Hi, I’m working on some bindings, but I’ve hit a couple of issues. Issue #1: how do I deal with “regular” structures that aren’t quite GTK+ classes? Essentially, I have a structure that’s returned from an already wrapped method, but I need to turn the wrapped structure into an appropriate Ruby object. I’m sure there’s already examples of this in the existing code, but I’m not familiar enough with the GTK+ C API to know where this has already been necessary. It has a destroy function, but it doesn’t have any of the rest of the type information necessary to use the normal macros, e.g. there isn’t a \_get\_type function. Can someone please help by either giving an example or pointing me to the appropriate place in the source? Issue #2: what’s the best way to wrap a structure of function pointers so that I can allow them to be implemented by a Ruby object? Given: struct foo { GtkWidget \* (\* create\_widget) (ContainerWidgetType \*widget, …) }; void widget\_set\_foo\_callbacks(ContainerWidgetType \*widget, foo \*callbacks, gpointer data) I’d like to end up with the following: class ContainerWidget def callbacks=(callbacks) … end class MyCallbacks def create\_widget(…) end cw = ContainerWidget.new cbw = MyCallbacks.new cw.callbacks = cbw Is this possible? Has something similar already been done somewhere? BTW, I figured out the answer to my earlier question when I found how the sort functions work for the list store. The example is in there. 66 static gint 67 sort\_func(model, a, b, func) 68 GtkTreeModel \*model; 69 GtkTreeIter \*a, \*b; 70 gpointer func; 71 { 72 a-\>user\_data3 = model; 73 b-\>user\_data3 = model; 74 return NUM2INT(rb\_funcall((VALUE)func, id\_call, 2, GTKTREEITER2RVAL(a), 75 GTKTREEITER2RVAL(b))); 76 } 77 78 static VALUE 79 treesortable\_set\_sort\_func(self, sort\_column\_id) 80 VALUE self, sort\_column\_id; 81 { 82 volatile VALUE func = rb\_block\_proc(); 83 G\_RELATIVE(self, func); 84 gtk\_tree\_sortable\_set\_sort\_func(\_SELF(self), NUM2INT(sort\_column\_id), 85 (GtkTreeIterCompareFunc)sort\_func, 86 (gpointer)func, NULL); 87 return self; 88 } 89 Thanks in advance, ast Andrew S. Townley [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) [http://atownley.org](http://atownley.org) ---
**Author:** ![Andrew\_SSTownley](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/d07c76/32.png) [@Andrew\_SSTownley](https://www.ruby-forum.com/u/Andrew_SSTownley)\ **Post date:** [October 18, 2008, 7:42am UTC](https://www.ruby-forum.com/t/binding-questions/151162/2 "2008-10-18T07:42:04Z")
Hi, In [1224244386.12922.31.camel@linna](mailto:1224244386.12922.31.camel@linna) “[ruby-gnome2-devel-en] Binding questions” on Fri, 17 Oct 2008 12:53:06 +0100, “Andrew S. Townley” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > void widget\_set\_foo\_callbacks(ContainerWidgetType \*widget, foo \*callbacks, gpointer data) > end > > cw = ContainerWidget.new > cbw = MyCallbacks.new > cw.callbacks = cbw > > Is this possible? Has something similar already been done somewhere? Yes. You will change id\_call to rb\_intern(“create\_widget”) in the below example. > 73 b-\>user\_data3 = model; > 84 gtk\_tree\_sortable\_set\_sort\_func(\_SELF(self), NUM2INT(sort\_column\_id), > 85 (GtkTreeIterCompareFunc)sort\_func, > 86 (gpointer)func, NULL); > 87 return self; > 88 } > 89 ## Thanks, kou