[Kde-perl] Overloading of Qt::ToolTip::maybeTip doesn't work

[Richard Dale]

On Thursday 28 October 2004 21:14, Ole Christensen wrote:
> Richard,
>
> unfortunately the patch you suggested does not fix the problem.
> Everything unchanged. Find the corresponding output below. Note the "--
> Ole" ;-) So the right lib actually gets used. The mapObject function
> obviously does not get called at all in this context. I put an fprintf
> there which is not reached.
mapObject() should get called when the instance of Qt::ToolTip is created. 
These two lines look for the instance in the map before trying to call the 
virtual method:

 SV *obj = getPointerObject(ptr);
 smokeperl_object *o = sv_obj_info(obj);

If it isn't found, you get the 'Cannot find object.. ' error.

> virtual 0x8746220->QToolTip::maybeTip() called
> Cannot find object for virtual method -- Ole
>
> I applied the patch on a fresh cvs export from sourceforge. Is there
> anything else I could do to track down the problem? Thanks in any case
> for your help.
Can you post the source of a test program to make it possible to reproduce the 
problem? You can add 'use Qt::debug qw( gc );' at the top of your program, to 
produce a debugging trace of the garbage collection and C++ to perl instance 
mapping.

-- Richard
>
> Richard Dale wrote:
> > On Wednesday 27 October 2004 22:48, Ole Christensen wrote:
> >>Hi,
> >>
> >>I am trying to implement a dynamic tooltip. The problem is that
> >>overloading Qt::ToolTip::maybeTip does not work for me. I already have
> >>reimplemented virtual functions in perl, but for some reason it does not
> >>work for maybeTip. QToolTip is not a subclass of QObject. Does that
> >> matter?
> >>
> >>When I switch on debugging of virtual functions I get:
> >>
> >>virtual 0x8772ea0->QToolTip::maybeTip() called
> >>Cannot find object for virtual method
> >>
> >>I am using
> >>PerlQt 3.008
> >>Qt 3.3.3
> >>perl 5.8.2
> >
> > I had the same problem as this with qtruby. Here is the entry from the
> > qtruby ChangeLog:
> >
> >  * If a class doesn't have a virtual destructor, then no mapping was
> > being kept from the C++ instance to the corresponding ruby value. If the
> > class had virtual method callbacks, this meant that the ruby instance
> > couldn't be found, and the callback couldn't be made.
> >
> >  * Hence, the Qt::ToolTip callback in examples/qt-examples/tooltip didn't
> >    work, as that class doesn't have a virtual destructor.
> >
> > For PerlQt, you would need to remove this test from the mapObject()
> > function in Qt.xs:
> >
> >     if(!c.hasVirtual() ) {
> >  XSRETURN_EMPTY;
> >     }
> >
> > void
> > mapObject(obj)
> >     SV *obj
> >     CODE:
> >     smokeperl_object *o = sv_obj_info(obj);
> >     if(!o)
> >         XSRETURN_EMPTY;
> >     SmokeClass c( o->smoke, o->classId );
> > //    if(!c.hasVirtual() ) {
> > // XSRETURN_EMPTY;
> > //    }
> >     mapPointer(obj, o, pointer_map, o->classId, 0);
> >
> > So that a mapping of the pointer from a C++ instance to a perl instance
> > is always kept.
> >
> > -- Richard
> > _______________________________________________
> > Kde-perl mailing list
> > Kde-perl at kde.org
> > https://mail.kde.org/mailman/listinfo/kde-perl
>
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