Quoth Andrew Potter:
> void gui_print(const Glib::ustring& str) {
> /* Get a function pointer to the set_text method we want to
> * use. We must explicitly declare the method pointer
> * signature because Gtk::TextBuffer::set_text is an
> * overloaded method. */
> void (Gtk::TextBuffer::*fptr)(const Glib::ustring&) =
> &Gtk::TextBuffer::set_text;
>
> /* Create a functor that points at the TextBuffer method we
> * want to use. Because tb is a Glib::RefPtr and sigc::mem_fun
> * needs the actual Gtk::TextBuffer object, we must use
> * operator->(). See GNOME Bugzilla #495762. */
> sigc::slot<void, const Glib::ustring&> set_text_functor =
> sigc::mem_fun(tb.operator->(), fptr);
>
> /* Bind the arguments of the functor to create a
> * sigc::slot<void> that can be sent to the callback
> * dispatcher.
> */
> sigc::slot<void> bound_functor = sigc::bind(set_text_functor,
> str);
>
> /* callback_dispatcher can execute any sigc::slot<void> on the
> * Main Loop. Since we have one now, send it.
> */
> callback_dispatcher.send(bound_functor);
> }
Given that sigc magic is hard for many people, you might want to simplify
this with a helper method:
// Called from the blocking operation in the worker thread
void gui_print(const Glib::ustring& str) {
sigc::slot<void, const Glib::ustring&> print_functor =
sigc::mem_fun(this, &Example::gui_print_ui);
sigc::slot<void> bound_functor = sigc::bind(print_functor, str);
callback_dispatcher.send(bound_functor);
}
// Called on the UI thread when the worker thread calls gui_print
void gui_print_ui(const Glib::ustring& str) {
tb->set_text(str);
}
This would make it easier for people to modify the actual action taken in
gui_print_ui.
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