From: Richard Dale <Richard_Dale@...>
Date: 2005-02-07T21:30:14+09:00
Subject: Re: Korundum: error when overriding a KDE::RootPixmap method

<posted & mailed>

Richard Dale wrote:

> Martin Traverso wrote:
> 
>> Hi,
>> 
>> I'm experimenting a bit with Korundum, but I'm having some problems. I
>> have the following code:
>> 
>> require 'Korundum'
>> 
>> app = Qt::Application.new([])
>> widget = Qt::Widget.new
>> pixmap = KDE::RootPixmap.new(widget)
>> 
>> class << pixmap
>>         def updateBackground(x)
>>                 puts "update background"
>>         end
>> end
>> 
>> pixmap.start
>> 
>> widget.show
>> app.setMainWidget(widget)
>> app.exec
>> 
>> When I run it I get this error:
>> 
>> ArgumentError: Cannot handle 'KSharedPixmap*' as argument of virtual
>> method KRootPixmap::updateBackground
>>         from /usr/local/lib/ruby/site_ruby/1.8/Qt/qtruby.rb:128:in
>> `method_missing'
>>         from /usr/local/lib/ruby/site_ruby/1.8/Qt/qtruby.rb:128:in
>>         `qt_invoke' from
>>         /usr/local/lib/ruby/site_ruby/1.8/Qt/qtruby.rb:128:in
>> `method_missing'
>>         from /usr/local/lib/ruby/site_ruby/1.8/Qt/qtruby.rb:128:in `exec'
>> 
>> If I remove the class << pixmap ... end section the program runs ok (but
>> does not do what I want, of course). Any idea of what the error means in
>> this context? What am I doing wrong?
> That means that 'KSharedPixmap*' is an unknown argument type, and can't be
> marshalled from a C++ instance to a ruby value.
> 
> The problem is that the KSharedPixmap code in ksharedpixmap.h is bracketed
> with:
> 
> #ifdef Q_WS_X11
> ...
> 
> #endif
> 
> And at the moment platform specific code is ignored when generating the
> bindings, so that class isn't added to the Smoke library's runtime, and
> can't be used from Korundum.
> 
> As it happens I was just looking at another '#ifdef' related problem for
> Q_OS_UNIX - that code was being skipped too. I'll try and fix this for the
> next release of Korundum (ie for KDE 3.4).
I've tried getting the KSharedPixmap class wrapped, but it uses multiple
inheritance with a diamond shaped hierachy and I had trouble getting the
C++ code for the binding to compile. So it might not be possible to include
it I'm afraid.

-- Richard