On Tue, 2006-11-28 at 17:27 -0700, Chris wrote:> Hello,> > I am new to gtk.> To learn the language I am writing simple> programs.> I want to be able to create 3 buttons, named> Button 1, Button 2 & Button 3.> If I explicitly initialize them it works.> When I pull the Initilize into a for loop> things start to go wrong.> I think that I am either not using the proper type> or not properly casting them.> The result is a segmentation error when I compile> which I think means a pointer is not correct.> If anyone knows how to fix this issue, it would be> greatly appreciated.> I have placed in bold the two sections> that I think apply to the problem.> > My code is as follows:> > #include <stdlib.h>> #include <stdio.h>> #include <string.h>> #include <gtk/gtk.h>> > [... snip ...]>> for (i=1; i<=3; i=i+1)> {> > *label = (gpointer)"Button ";
Here you are assigning to '*label', yet you have not yet initialized'label'. Hence the crash. (Indeed, gcc does not even compile this code)
> strcat (label, (gpointer) i);
This does not make much sense.
> button = gtk_button_new_with_label ((gchar *)label);> [... snip ...]> }
Here comes code that does a bit better:
/************************** begin example **************************/#include <stdlib.h>#include <stdio.h>#include <string.h>#include <gtk/gtk.h>
static void button_cb (GtkWidget *widget, gpointer data){ g_print ("Hello - %s was pressed\n", (gchar *) data);}
static void delete_event_cb (GtkWidget *widget, GdkEvent *event, gpointer data){ g_print ("A delete event has occurred\n"); gtk_main_quit();}
int main (int argc, char *argv[]){ GtkWidget *window; GtkWidget *button; GtkWidget *box1; gint i;
gtk_init (&argc, &argv);
window = gtk_window_new (GTK_WINDOW_TOPLEVEL); gtk_window_set_title (GTK_WINDOW (window), "Test Program"); gtk_container_set_border_width (GTK_CONTAINER (window), 50); g_signal_connect (G_OBJECT (window), "delete_event", G_CALLBACK (delete_event_cb), NULL);
box1 = gtk_hbox_new (FALSE, 0); gtk_container_add (GTK_CONTAINER (window), box1);
for (i=1; i<=3; i=i+1) { char *label;
label = g_strdup_printf ("Button %d", i); button = gtk_button_new_with_label (label); g_free (label); g_signal_connect (G_OBJECT (button), "clicked", G_CALLBACK (button_cb), label); gtk_box_pack_start (GTK_BOX(box1), button, TRUE, TRUE, 0); }
gtk_widget_show_all (window);
gtk_main ();
return 0;}/************************** end example **************************/
Hope this helps a bit.
You should probably consult a C book, by the way.
-- m
-- Mariano Suárez-Alvarezhttp://www.gnome.org/~mariano
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