Connect to Gtk::Window signal_delete_event

Question

I want to connect a signal to window.signal_delete_event, but it fails with the following error messages:

• no match for call to ‘(sigc::bound_mem_functor0) (_GdkEventAny* const&)’ OpticalInput
• return-statement with a value, in function returning 'void' [-fpermissive]
• void value not ignored as it ought to be

That is the code line causing the error:

window.signal_delete_event().connect(sigc::mem_fun(this,&GUIWindow::onExitClicked));

The pointed member function is this one:

void GUIWindow::onExitClicked()
{
    *state = false;
    Gtk::Main::quit();
}

Any ideas on how to fix this?

Answer 1

Your method must match the signature of the signal. In the gtkmm documentation for signal_delete_event(), the following prototype is given:

bool on_my_delete_event(GdkEventAny* event)

Using your naming, the method must be defined as follows:

bool GUIWindow::onExitClicked(GdkEventAny* event) { ... }

The return value is used to indicate whether or not you have completely handled the event. If you return true, other handlers for this event will not see it.