Re: Problem with subclassing with Glib::Object::Subclass and Gtk3

[Yuri Myasoedov <ymyasoedov yandex ru>]

Hm. It seems the problem is in Glib::Object::Introspection XS function _invoke_fallback_vfunc:

__PACKAGE__->_invoke_fallback_vfunc($provider_package,
                                                $vfunc_name,
                                                $implementer_package,
                                                 _);

It can't handle undef parameters. For example, in "screen-changed" handler (I didn't connect any handlers to 
this signal in my class):

void user_function (GtkWidget *widget, GdkScreen *previous_screen, gpointer   user_data)

where "previous_screen" -- the previous screen, or NULL if the widget was not associated with a screen before.

In my case "previous_screen" is undef because it should be NULL in C. But Glib::Object::Introspection 
requires that "previous_screen" should be Gtk3::Gdk::Screen and it fails when "previous_screen" is undef: 
"undef is not of type Gtk3::Gdk::Screen".

09.04.2015, 22:29, "Yuri Myasoedov" <ymyasoedov yandex ru>:
>  Hi!
>
>  I have a problem with migration of my code to Gtk3. Just a simple example. I want to subclass from 
> Gtk3::Button with Glib::Object::Subclass.
>  There is no new signals, no properties and so on... BTW, when I switched to Gtk3, I have to define two 
> additional
>  signals, PARENT_SET and HIERARCHY_CHANGED. This code just works if I replace Gtk3 to Gtk2. But it doesn't
>  when I use Gtk3. I've got a error: "undef is not of type Gtk3::Gdk::Screen at 
> /usr/lib/perl5/site_perl/Glib/Object/Introspection.pm line 246."
>
>  What's wrong with it? Can I still use Glib::Object::Subclass for inheritance for Gtk3?
>
>  #!/usr/bin/perl
>
>  use strict;
>  use warnings;
>
>  package MyButton;
>
>  use Gtk3;
>
>  use Glib::Object::Subclass
>      Gtk3::Button::,
>      signals => {},
>      properties => [],
>      ;
>
>  sub INIT_INSTANCE {
>      my $self = shift;
>      return $self;
>  }
>
>  sub PARENT_SET {
>      my $self = shift;
>      warn "PARENT_SET was called\n";
>  }
>
>  sub HIERARCHY_CHANGED {
>      my $self = shift;
>      warn "HIERARCHY_CHANGED was called\n";
>  }
>
>  package main;
>
>  use Gtk3 -init;
>
>  my $window = Gtk3::Window->new();
>  $window->signal_connect(delete_event => sub { Gtk3->main_quit() });
>
>  my $my_button = MyButton->new(label => "Test");
>  $window->add($my_button);
>  $window->show_all();
>  Gtk3->main();
>
>  [ysm helios tmp]$ perl test.pl
>
>  (1.pl:7631): Gtk-WARNING **: Theme parsing error: gtk-widgets.css:2:16: Theming engine 'adwaita' not found
>  PARENT_SET was called
>  HIERARCHY_CHANGED was called
>  undef is not of type Gtk3::Gdk::Screen at /usr/lib/perl5/site_perl/Glib/Object/Introspection.pm line 246.
>  _______________________________________________
>  gtk-perl-list mailing list
>  gtk-perl-list gnome org
>  https://mail.gnome.org/mailman/listinfo/gtk-perl-list