Re: Gtk::GladeXML and Gtk::CList select-row callback prototype

[René Seindal <rene seindal dk>]

I just found this in the archive, which explains the problem.

http://mail.gnome.org/archives/gtk-perl-list/2000-March/msg00023.html

René.


On Sat, Jan 25, 2003 at 09:54:06AM +0100, René Seindal wrote:
> Hi,
> 
> I am fairly new to writing Gtk apps with perl, but I like it a lot.  I
> have run into a problem, though.
> 
> I have an apps made with glade.  There is a Clist with a select-row
> callback.  There is no data associated with the callback in glade.
> 
> I'd expect to see a callback prototype of (I use an OO approach, hence
> the $this as the first argument)
> 
> sub on_list_select_row {
>     my ($this, $list, $row, $column, $event, $user_data) = @_;
> }
> 
> as per the C api.
> 
> It appears that I get:
> 
> sub on_list_select_row {
>     my ($this, $list, $user_data, $row, $column, $event) = @_;
> }
> 
> that is the $user_data has been shifted in front of the other parameters
> to the callback.
> 
> If I attach the signal by hand I get the same result, more or less.
> 
> If I use
> $clist->signal_connect('select-row'=>sub { $this->on_list_select_row(@_); });
> 
> the callback get these args:
> ($this, $clist, $row, $column, $event)
> 
> If I use
> $clist->signal_connect('select-row'=>sub { $this->on_list_select_row(@_); },
> 		       $arg);
> 
> the callback gets
> ($this, $clist, $arg, $row, $column, $event)
> 
> I can add more arguments to signal_connect
> $clist->signal_connect('select-row'=>sub { $this->on_list_select_row(@_); },
> 		       $arg1, $arg2, $arg3);
> 
> and the callback gets
> ($this, $clist, $arg1, $arg2, $arg3, $row, $column, $event)
> 
> 
> Frankly, I find this rather confusing.  Why on earth are the user_data
> arguments to signal_connect() stuck in the middle of the callback
> arguments?   I'd definitely expect to see them at the end.
> 
> Is this a bug or an undocumented feature?
> 
> 
> I use Debian testing with libgtk-perl and libgladexml-perl 0.7008-1.2.
> 
> 

-- 
René Seindal (rene seindal dk)              http://www.seindal.dk/rene/