Re: GList empty after iteration?

[Bernhard Schuster <schuster bernhard googlemail com>]

2011/9/12 Craig <craigbakalian verizon net>:
> Hi All,
>
> I am confused about GList. My application is parsing a file and creating
> midi data with it. I am using GList to store the midi data. ÂI have
> created a GtkListStore to view the parsed data (to insure I am parsing
> the data properly). ÂSo, below I iterate through the GList and "copy"
> the data into a tree view. ÂBut, I am shocked to see that after I
> iterate through the GList, I cannot iterate through the list again. ÂI
> have debugged the list after the iteration with g_list_length(events)
> which shows the list length at 0. ÂWhat is up with this? ÂThe first
> while loop has data, the second while loop has not data. The code is
> below-->
>
> Â Â Â ÂGtkTreeIter tree_iter;
> Â Â Â Âevents = g_list_reverse(events);
shallowcopy = events;
> Â Â Â Âevents = g_list_first(events);
> Â Â Â Âwhile(events)
> Â Â Â Â{
> Â Â Â Â Â Â Â Âgtk_list_store_append (list_store, &tree_iter);
> Â Â Â Â Â Â Â Âstruct midi_event *me = events->data;
> Â Â Â Â Â Â Â Âgtk_list_store_set(list_store, &tree_iter,
> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 0, me->time_stamp,
> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 1, me->event_type,
> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 2, me->message1,
> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 3, me->message2,
> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â-1);
> Â Â Â Â Â Â Â Âevents = g_list_next(events);
> Â Â Â Â}
> Â Â Â Â/// this is where the list appears to be empty!!!!
events = shallowcopy;
> Â Â Â Âwhile(events)
> Â Â Â Â{
> Â Â Â Â Â Â Â Âg_print("midi event \n");
> Â Â Â Â Â Â Â Âevents = g_list_next(events);
> Â Â Â Â}
>
> Thanks for any help!
Your first loop ands when your event is zer0. Youn need to use a
second pointer for your second iteration which still points to the
first item in the actual list.

Hope that helps.

Regards

Bernhard