Path: utzoo!utgpu!utstat!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!hplabs!hpfcdc!hpfclp!diamant
From: diamant@hpfclp.SDE.HP.COM (John Diamant)
Newsgroups: comp.windows.x
Subject: Re: Re: XtReparentWidget (How about XtCopyWidget)
Message-ID: <9740089@hpfclp.SDE.HP.COM>
Date: 10 Apr 89 00:35:41 GMT
References: <9941@polyslo.CalPoly.EDU>
Organization: HP SESD, Fort Collins, CO
Lines: 32

> >The Toolkit does contain enough information.  The size of a widget w can
> >be obtained as follows:
> >
> >    XtClass(w)->core_class.widget_size;
> >
> >With that, you can malloc up a suitable sized chunk of memory and do a raw
> >memory copy using bcopy to the new location.  
> 
>   On the contrary, this is not general at all.  What if the widget has
>   non-core part data?

I don't see how this has anything to do with it.  The widget_size is filled
in with the size of the entire widget record, not the size of the CorePart,
so it will copy all data in the widget.

>   Also, if such a widget could be created you'd need
>   a mechanism to inform the parent that a child has been created behind
>   it's back.

Well, yes.  It is not general in that sense.  In fact, someone else pointed
out via mail that this will cause trouble if there are pointers in the
structure as both widgets would write to common data.  That's true, but I
was only attempting to answer a question in the original note which said
that the original would be destroyed after the copy was made, so it
shouldn't have mattered much.  I never understood how this was supposed
to solve the reparenting problem.  It appears to me that it does not.


John Diamant
Software Engineering Systems Division
Hewlett-Packard Co.		ARPA Internet: diamant@hpfclp.sde.hp.com
Fort Collins, CO		UUCP:  {hplabs,hpfcla}!hpfclp!diamant