Re: GLib/GList on Windows XP

["Jasper St. Pierre" <jstpierre mecheye net>]

On Fri, Aug 31, 2012 at 12:56 PM, Gary Dumer <gedumer yahoo com> wrote:
> Hi,
>
> I'm having a problem that may be the result of my inexperience with GLib or
> it could be an issue with Glib on Windows XP.
>
> I'm having several problems. The first is with g_list_index always returning
> 0. Am I correct that g_list_index searches the entire list starting at 0 to
> find the requested "data" OR does g_list_index start at the current position
> to find the data? If it's the former then I'm having a problem, if it's the
> latter then I assume that I have to set the starting position myself before
> initiating g_list_index.
>
> If I'm positioned at the last element in the list and do this:
>
> g_list_index(x, "something")
>
> it returns 0 even though "something" exists in the list. However, if I do
> this instead:
>
> g_list_index(g_list_first(x, "something"), "something")
>
> it works. In this case I'm obviously setting the position of the list to the
> correct position before requesting the index... which seems redundant to me.
> I'm confused.

g_list_index requires that you pass the head list node.

> The second issue is with g_list_nth_prev. The docs suggest that if I try to
> move beyond the beginning of the list, g_list_nth_prev will return NULL and
> the list will remain at the position prior to the invalid g_list_nth_prev.
> For example, if I have a list containing 10 elements and I'm positioned at
> the last element, if I do the following:
>
> if (NULL == (x = g_list_nth_prev(x, 99)))
>   print an error message...
> else
>   proceed...
>
> the program crashes. But if I do this:
>
> if (NULL == g_list_nth_prev(x, 99))
>   print an error message...
> else
>   x = g_list_nth_prev(x, 9);
>
> it works correctly. The question is... should it work in the first case? My
> understanding of the docs suggest it should.

The first example should work. Can you give a more complete, runnable
example that exhibits the crash?

> The third issue relates to the second one. Any GList function that can
> potentially advance the list beyond its boundaries is open to the same issue
> above. So any of the following functions can end with the same potential
> results:
>
> g_list_nth
> g_list_nth_data
> g_list_next
> g_list_previous
>
> Maybe others as well.
>
> That's about it. Thanks for any help you can offer.
>
> Gary
>
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-- 
  Jasper