Re: [gtk-list] Re: question about resizing & combos

[Gustavo Joćo Alves Marques Carneiro <ee96090 fe up pt>]

	I can't find any other problem, maybe because there isn't enough
documentation available on GtkCombo. I, myself, have some doubts about its
usage, and I hope one of the developers can englighten me:

	1.- The function 'gtk_combo_set_popdown_strings( GTK_COMBO(combo),
glist)': 
	o does it copy the glist we supply but not the data pointed to by
its elements, or,
	o does it copy the glist and the data (strings), or,
	o it doesn't copy anything and takes ownership of the glist and
the strings, or,
	o it takes ownership of the glist but not its data.

	2.- The function 'gtk_combo_set_popdown_strings( GTK_COMBO(combo),      
glist)', when the combo already has a glist of strings
	o does it free the previous glist? If so, its data also?

	3.- In case the combo takes ownership of the glist, do changes in
the glist automatically appear in the widget?

	So, as you can see, I'm also a bit confused about Combos :).

On Wed, 27 Oct 1999, Giaslas Georgios wrote:

> i think you have right Gustavo, but this code is just a sample from
> a part of a program i'm writing
> in my real programm the strings are `dynamic` so there
> must be another problem
> 
> On Wed, 27 Oct 1999, [ISO-8859-1] Gustavo Joćo Alves Marques Carneiro wrote:
> 
> > 	Ok. I think I found another problem. You have created a glist that
> > contains a list of 'static' strings. Those strings are embedded in the
> > program code by the compiler and can't be freed. Each item of glist->data
> > is a pointer to one of those static strings. It's not dynamic memory
> > allocation, so you don't have to bother releasing it -- it will be done
> > automatically. Just remove the g_free. 
> > 
> > 
> > On Wed, 27 Oct 1999, Giaslas Georgios wrote:
> > 
> > > Thank you Gustavo for replying so quick 
> > > 
> > > i tried to put g_free(l->data) before g_list_remove
> > > but i get a segmentation fault when the program tries to execute g_free
> > > 
> > > i also checked with gdb that 'while' doesn't ever result 
> > > in an endless loop.
> > > 
> > > So, there must be another problem
> > > 
> > > Thanx anyway
> > > -----------------------------------------
> > > > 2) i have a combo box and when the user selects
> > > >    a string i want all the strings before this to be removed.
> > > >    i've done it and when i change the comboentry using
> > > >    arrow keys it's ok. but when it's changed using the
> > > >    mouse i get a segmentation fault.
> > > >    Is it a bug or it's my fault?
> > > >    please try the following little program to see what
> > > >    i mean exactly.
> > > >
> > > > (I use gtk+ version 1.2.6)
> > > >
> > > > Please reply this time...
> > > >
> > > > Thank you all
> > > >
> > > > -----------------------------
> > > > #include <gtk/gtk.h>
> > > >
> > > > GList *glist=NULL;
> > > >    gint active=0;
> > > >    GtkWidget *combo;
> > > >    GtkWidget *window;
> > > >
> > > >    static gint delete_callback(GtkWidget *widget, gpointer data)
> > > >    {
> > > >        gtk_main_quit();
> > > >        return(FALSE);
> > > >    }
> > > >
> > > >    void callback(GtkEntry *comboentry, gpointer data)
> > > >    {
> > > >        GList *l;
> > > >        gint cnt=0;
> > > >        if (active)
> > > >        {
> > > >            l=g_list_first(glist);
> > > >            while (g_strcasecmp(l->data, gtk_entry_get_text(comboentry)))
> > > >            {
> > > >                g_print("data %s deleted\n", (gchar *) l->data);
> > > >                glist=g_list_remove(glist, l->data);
> > > >                g_free(l->data);
> > > 
> > > >        g_free(l->data) should come before g_list_remove because it is
> > > >not guaranteed that the location pointed by 'l' is valid after you remove
> > > 
> > > >it from the list.
> > > 
> > > >                cnt++;
> > > >                l=g_list_first(glist);
> > > >            }
> > > >        Also, you should take care that this previous 'while' doesn't
> > > ever
> > > >result in an endless loop.
> > > 
> > > >            gtk_combo_set_popdown_strings(GTK_COMBO(combo), glist);
> > > >        }
> > > >    }
> > > >
> > > >    int main (int argc, char *argv[])
> > > >    {
> > > >        gtk_init(&argc, &argv);
> > > >        window=gtk_window_new(GTK_WINDOW_TOPLEVEL);
> > > >        gtk_signal_connect(GTK_OBJECT(window), "delete_event",
> > > >                            GTK_SIGNAL_FUNC(delete_callback), NULL);
> > > >        combo=gtk_combo_new();
> > > >        glist = g_list_append(glist, "String 1");
> > > >        glist = g_list_append(glist, "String 2");
> > > >        glist = g_list_append(glist, "String 3");
> > > >        glist = g_list_append(glist, "String 4");
> > > >        gtk_signal_connect(GTK_OBJECT(GTK_COMBO(combo)->entry),
> > > "changed",
> > > >  GTK_SIGNAL_FUNC(callback), NULL);
> > > >
> > > >        gtk_combo_set_popdown_strings( GTK_COMBO(combo), glist);
> > > >        gtk_container_add(GTK_CONTAINER(window), combo);
> > > >        gtk_widget_show_all(window);
> > > >        active=1;
> > > >        gtk_main();
> > > >        return 0;
> > > >    }
> > > > --------------------------
> > > >
> > > 
> > > 
> > > 
> > 
> > -- 
> > Gustavo J.A.M. Carneiro
> > World::Portugal::FEUP::DEEC::LEEC::TEC
> > [reinolinux.fe.up.pt/~ee96090]
> >                                        
> > 
> > -- 
> > To unsubscribe: mail -s unsubscribe gtk-list-request@redhat.com < /dev/null
> > 
> > 
> 
> --
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> 
> 

-- 
Gustavo J.A.M. Carneiro
World::Portugal::FEUP::DEEC::LEEC::TEC
[reinolinux.fe.up.pt/~ee96090]