Re: [gtkmm] Gtk::DrawingArea help required

["Timothy M. Shead" <tshead k-3d com>]

ej wrote:

> The button signal handler works fine when I comment out the expose event 
> handler connect line, but
> with that line the program fails to compile with the following :
>
> ejames sonata:/data/My_NEAT/StockDB/helloworld> g++ -o picture  main.cpp 
> Picture.cpp `pkg-config gtkmm-2.0 --cflags --libs`
> Picture.cpp: In constructor `Picture::Picture()':
> Picture.cpp:24: error: no matching function for call to `
>   Glib::SignalProxy1<bool, GdkEventExpose*>::connect(SigC::Slot0<void>)'
> /opt/gnome/include/gtkmm-2.0/glibmm/signalproxy.h:136: error: candidates 
> are:
>   SigC::Connection Glib::SignalProxy1<R, P1>::connect(const SigC::Slot1<R,
>   P1>&, bool) [with R = bool, P1 = GdkEventExpose*]

The signature of event handlers is dictated by the signal; in this case, 
you have to provide a function that takes GdkEventExpose* and returns bool:

bool Picture::on_expose_event(GdkEventExpose*)
{
    std::cout << "expose event generated" << std::endl;
}

Cheers,
Tim