Hello,
(my comments are inline, and please keep the discussion on list)
2011/5/19 Jan Spurný <[email protected]>:
> Hi,
>
> thanks again for your reply,
>
>> >> Did you have any problem with the following? it should be the first
>> >> thing you try (and is likely the correct thing):
>> >>
>> >> [CCode (cheader_filename = "oldlib.h")]
>> >> public static GLib.List<X> old_lib_make_x_list();
>> >
>> > Thanks for your reply, but unfortunately, it really WAS the first thing I
>> did
>> > - but because X is not reference counted, it resulted in errors like this:
>> >
>> > oldlib.vapi:61.33-61.36: error: duplicating X instance, use unowned
>> variable
>> or explicitly invoke copy method
>> > public static GLib.List<X> old_lib_make_x_list();
>> > ^
>>
>> Yeah, this error message is misleading. You should put unowned in your
>> loop and not in the bindings, i.e.
>>
>> foreach(unowned X myx in old_lib_make_x_list()) {
>> ...
>> }
>
> ok, that makes sense.. unfortunately, it won't help me much - it's probably my
> fault, I should've explained it better - I'm using GLib.List<X> returned from
Are you sure you aren't iterating over the returned list anywhere? The
error message you got suggests you are. (but maybe I'm mistaken)
> oldlib almost exclusively only to pass it to another oldlib function, so what
> I really need to do is something like this:
>
> void vala_func() {
> var list = old_lib_make_x_list();
> var list2 = old_lib_filter_list(list);
> var list3 = old_lib_obscure_function_xy(list, list2);
> old_lib_supercomplicated_function(list2, list3);
> }
>
> which in c (c99) I would write like this:
>
> void c_func()
> {
> GList *list = old_lib_make_x_list();
> GList *list2 = old_lib_filter_list(list);
> GList *list3 = old_lib_obscure_function_xy(list, list2);
> old_lib_supercomplicated_function(list2, list3);
>
> // old_lib_destroy_x_list destroys the list (by a call to g_list_free) but
> // also the contents (by a call to x_destroy for each element)
> old_lib_destroy_x_list(list);
> old_lib_destroy_x_list(list2);
> old_lib_destroy_x_list(list3);
> }
This should be exactly the the expected result (that is, if you don't
mind that valac uses __g_list_free__x_destroy_ instead of
old_lib_destroy_x_list)
> So I need some way how to get the return value of old_lib list generating
> functions and at the same time to make sure the list gets destroyed..
In general, you shouldn't worry much about memory management: if this
is something that is normally done in Vala (in your example, the user
should free both the list and its contents), just declare it normally.
> Please tell me if this is confusing, I'm not really good in english, so if
> this doesn't make sense, I'll try to write some minimal piece of code which
> could demonstrate my problem more clearly.
Your english is fine :-) And yes, a minimal reproduction of your
problem would really help.
Regards,
Abderrahim
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