RE: newbie and g_list*

["Dugas, Alan" <alan dugas analog com>]

I believe this occurs because your deleting/freeing an item from the glist
without updating the pointers of the previous and next items in the glist - they
still point to the freed memory.  Hope this helps.



				-- Stupid Genius

> ----------
> From: 	Michael P. Jarreau[SMTP:mike JACtrls com]
> Sent: 	Monday, January 29, 2001 2:01 PM
> To: 	gtk-list gnome org
> Subject: 	newbie and g_list*
> 
> I am running on linux.  I use scandir to look at a directory.  I do this
> periodically so that my GUI can update it's display when new data arrives.
> The scandir function mallocs memory for data and I add that to a list.  This
> code looks something like this (error checking removed):
> 
>     // This works fine.  It's here for background.
>     int n;
>     struct dirent **dirEntries = NULL;
>     n = scandir (directory, &dirEntries, 0, alphasort);
>     while (n)
>     {
>         list = g_list_append (list, dirEntries[n]->d_name);
>     }
>     free (dirEntries);
> 
> The free above does not remove the names, just the structure pointing to
> them.  It is malloced by scandir as are the arrays for the file names.  Note
> that I did not free the memory for those names.
> 
> Later, I want to remove one of them, so I locate it with function f().  And
> try
> 
>     // This works.
>     GList *tmp = f ();
>     list = g_list_remove (list, tmp->data);
> 
>     // This creates a segmentation fault and I don't understand why.
>     free (tmp->data);
> 
> I am led to believe that data is just a pointer.  I expect that it contains
> the pointer to the directory entry that I assigned to it in the
> g_list_append function.  Thus, I can nuke it whenever I want as long as I
> have already removed it from the list.  Is that correct?
> 
> Please ignore the ignorance.  I've searched the archive and found several
> discussions, but I have not learned from there.
> 
> Thanks,
> Mike
> 
> 
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