James,
> When doe s the error occur?
> 0. When program starts
> 1. When shutting down
> 2. When creating the text_view the first time
> 3. When creating the text_view the Nth time
>
> I will assume it happens durin shutdown (#1).
Yes you are correct. In the "real" application, the application
doesn't exit. It destroys the canvas and re-uses it with new controls.
Rather than debug that [monster], I reduced the application to
something more manageable that exhibit the same behavior.
> Yes, it should be handled like any other widget. The only special thing is
> its text_buffer! Consider gtk_text_view_new_with_buffer(), one is created
> automatically for when using the gtk_text_view_new() api. I don't think
> creating the GtkTextBuffer first would make any difference -- however, that
> where you are now. So try creating the GtkTextBuffer first, then use the
> ...with_buffer() api to create the view. This may produce a different
> result.
Interesting. I tried a few different things today and was able to get
the application to work as expected without crashing, but I don't like
the solution as now it appears I'm leaking memory. Any thoughts on why
if g_object_unref is called the application complains about the double
free? I modified the code as follows (mainly the button_click_event
handler was changed to handle the text buffer and to require clicking
the 'Quit' button twice for exiting the app - this was just done for
visibility reasons).
[code]
GtkWidget *main_window, *text_view, *box, *button;
GtkTextBuffer* buffer;
static void destroy_event(GtkWidget* widget, void* data)
{
gtk_main_quit();
}
static void button_click_event(void)
{
if (text_view != NULL)
{
gtk_container_remove(GTK_CONTAINER(box), text_view);
text_view = NULL;
// leaking memory???
// g_object_unref(G_OBJECT(buffer));
buffer = NULL;
}
else
{
gtk_widget_destroy(main_window);
main_window = NULL;
}
}
int main(int argc, char* argv[])
{
// initialize multi-threading within GLib
g_thread_init(NULL);
// initialize multi-threading within GDK
gdk_threads_init();
// acquire thread lock
gdk_threads_enter();
gtk_init(&argc, &argv);
// create main window
main_window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
if (main_window == NULL)
abort();
g_signal_connect(G_OBJECT(main_window), "destroy",
G_CALLBACK(destroy_event), NULL);
gtk_widget_show(main_window);
box = gtk_vbox_new(FALSE, 5);
if (box == NULL)
abort();
gtk_widget_show(box);
gtk_container_add(GTK_CONTAINER(main_window), box);
buffer = gtk_text_buffer_new(NULL);
if (buffer == NULL)
abort();
text_view = gtk_text_view_new_with_buffer(buffer);
if (text_view == NULL)
abort();
gtk_widget_show(text_view);
gtk_box_pack_start(GTK_BOX(box), text_view, TRUE, TRUE, 5);
button = gtk_button_new_with_label("Quit");
if (button == NULL)
abort();
g_signal_connect(G_OBJECT(button), "clicked",
G_CALLBACK(button_click_event), NULL);
gtk_widget_show(button);
gtk_box_pack_start(GTK_BOX(box), button, TRUE, TRUE, 5);
// run the main loop
gtk_main();
// release thread lock
gdk_threads_leave();
return 0;
}
[/code]
--
Mark
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