treeview---->cursor-changed--->destroy---->seg fault

[P V Mathew <pvmathew softhome net>]

Hello,

I had earlier sent a mail on the following lines:

 >I have a gtk2 program which uses gtk tree view.
 >I have written a handler for the cursor changed signal.
 >The handler calls gtk_widget_destroy on the parent container
 >widget.
 >I am getting segmentation fault, if I move the
 >cursor using the mouse. If I move the cursor using the
 >key board all seems fine.

 >Would some one help me on why this occurs, and how
 >to solve it?

  The line which says "If I move the cursor using the mouse
  has caused confusion, I think. I am sorry. What I meant was,
if I click on any row in the displayed view, segmentation
fault occurs. If I click on any row I think a cursor-changed
signal gets automatically emitted. But why the seg fault?

The sample code, which was taken from a tutorial, and modified
to demonstrate the point, is once again enclosed, after removing
those useless comments.

****************** beginning of code ******************

/*
 * Compile with:
 *  gcc -o helloworld helloworld.c `pkg-config --cflags --libs gtk+-2.0`
 *
 */

#include <gtk/gtk.h>
#include <stdio.h>

enum
{
  COL_NAME = 0,
  COL_AGE,
  NUM_COLS
} ;

struct allv
{
        GtkWidget *win;
        GtkWidget *view;
} av;
static GtkTreeModel *
create_and_fill_model (void)
{
  GtkListStore  *store;
  GtkTreeIter    iter;
  store = gtk_list_store_new (NUM_COLS, G_TYPE_STRING, G_TYPE_UINT);

  /* Append a row and fill in some data */
  gtk_list_store_append (store, &iter);
  gtk_list_store_set (store, &iter,
                      COL_NAME, "Heinz El-Mann",
                      COL_AGE, 51,
                      -1);

  /* append another row and fill in some data */
  gtk_list_store_append (store, &iter);
  gtk_list_store_set (store, &iter,
                      COL_NAME, "Jane Doe",
                      COL_AGE, 23,
                      -1);

  /* ... and a third row */
  gtk_list_store_append (store, &iter);
  gtk_list_store_set (store, &iter,
                      COL_NAME, "Joe Bungop",
                      COL_AGE, 91,
                      -1);

  return GTK_TREE_MODEL (store);
}

static GtkWidget *
create_view_and_model (void)
{
  GtkTreeViewColumn   *col;
  GtkCellRenderer     *renderer;
  GtkTreeModel        *model;
  GtkWidget           *view;

  view = gtk_tree_view_new ();

  /* --- Column #1 --- */

  renderer = gtk_cell_renderer_text_new ();
  gtk_tree_view_insert_column_with_attributes (GTK_TREE_VIEW (view),
                                               -1,
                                               "Name",
                                               renderer,
                                               "text", COL_NAME,
                                               NULL);

  /* --- Column #2 --- */

  renderer = gtk_cell_renderer_text_new ();
  gtk_tree_view_insert_column_with_attributes (GTK_TREE_VIEW (view),
                                               -1,
                                               "Age",
                                               renderer,
                                               "text", COL_AGE,
                                               NULL);

  model = create_and_fill_model ();

  gtk_tree_view_set_model (GTK_TREE_VIEW (view), model);

  g_object_unref (model); /* destroy model automatically with view */

  return view;
}
void my_signal(GtkTreeView *t,gpointer g);
int MainWindow()
{
        
        GtkWidget *window;
        GtkWidget *view;
          window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  g_signal_connect (window, "delete_event", gtk_main_quit, NULL);
  av.win = window;
  view = create_view_and_model ();
  av.view = view;
  g_signal_connect(view, "cursor-changed", 
(GCallback)my_signal,(gpointer)&av);
  gtk_container_add (GTK_CONTAINER (window), view);
  gtk_widget_show_all (window);

}
void my_signal(GtkTreeView *t,gpointer g)
{
        static int n=1;
        if (n != 1)
        {
        fprintf(stderr,"%s\n","signal received");
                n = 1;
                gtk_widget_destroy(((struct allv*)g)->win);
                //MainWindow();
        }
        else
                n++;
}
int
main (int argc, char **argv)
{
  gtk_init (&argc, &argv);
  MainWindow();
  gtk_main ();
  return 0;
}
*************************************end of code *************
Last time I had sent the sample code as attachment.
It did not appear along with the copy of the
message I received. May be the list strips attachments.
so excuse me for sending again.


Does this mean that one cannot destroy the widget
in a CallBack function? Or Is this a Gtk bug?

I am using  debian testing linux. with libgtk2 version 2.4.9-1.

p v mathew