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List:       kde-core-devel
Subject:    Re: Kwin freezes
From:       Michael Matz <matzmich () cs ! tu-berlin ! de>
Date:       2000-05-31 0:59:27
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Hi,

On Tue, 30 May 2000, Rik Hemsley wrote:
> if (!block_focus &&
>     options->focusPolicyIsReasonable() &&
>     !focus_chain.isEmpty())
> {  
>   ClientList::ConstIterator it = focus_chain.fromLast();  
>   do {
>     if ((*it)->isVisible()) {
>       requestFocus(*it);
>       break;
>     }
>     it--;
>   } while (it != focus_chain.begin());
> }

This breaks the loop, if (it==focus_chain.begin()), but before evaluating
begin(). Note that begin() is (unlike end()) an element of the list. Use
something like for(it=bla.fromLast();it!=bla.end(); --it) {}

I think the Qt docu is wrong in saying, that --begin() is undefined, as
then there would be no nice way to recurse backwards. And indeed the
reality is another, --begin()==end(). (At least as I last looked at all
the loops in kwin)


Ciao,
Michael.

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