[Development] Question about QCoreApplicationData::*_libpaths

Marc Mutz marc.mutz at kdab.com
Sun Jan 31 00:38:41 CET 2016

On Friday 22 January 2016 22:51:30 Kevin Kofler wrote:
> Marc Mutz wrote:
> > Judging from the comments on my blog post from 2010(!), when they hear
> > QList people first think std::list (ie. linked list). Then they see that
> > there's also a QLinkedList and start thinking that QList is something
> > like std::deque. And then, if they are lucky, they realise it isn't
> > that, either. Because both of those std containers guarantee stability
> > of references under appends, as does QList _by default_.
> It's funny, because having learned C++ mostly together with Qt, I just see
> std::list and std::deque as terse and incomplete names, and so std::list is
> what I think is incorrectly named, not QList. :-) Qt would never approve a
> name like "deque" in an API review!
> Sure, Qt 3's QList was also a linked list, but I have internalized the Qt 4
> changes by now.

It's funny, because having learned C++ mostly together with Qt, and having 
ported Qt code from Qt 2 to Qt 3 and Qt 4 and 5, I find solace in the API 
stability of the STL. So we seem to have the same background, but have drawn 
different conclusions. Interesting. Maybe I have ported Qt containers one too 
many times.

> >> Everything else is a blatant API abuse.
> > 
> > Tell that to the authors of QToolBox and QDataWidgetMapper (off the top
> > of my head). Better yet: put code where your mouth is and fix that
> > blatant API abuse. I'll be more than happy to give you a +2 on that one.
> Oh, there's code inside Qt that sits on references into containers? Ewww!
> >> undeprecate QtAlgorithms
> > 
> > And this is where I stop taking you seriously, sorry. You can demand such
> > nonsense, but if you do, _do_ the work yourself. Go. Implement those 80+
> > algorithms from the STL for Qt. Or play god deciding which are the ones
> > "no- one will ever need" or "should never use" - IYHO.
> I'd already be happy with those that were (are, actually) already there.
> I'd rather have 10-20 common algorithms with a convenient API than 80+
> obscure ones that force me to use iterators (especially the boilerplate
> .begin() and .end() iterators that will be used in 99+% of the cases –
> copy&paste programming sucks).

I don't like how you demand work from others, but don't want to do any work on 
Qt yourself.

I note that you have not, yet, submitted a change to remove those QList uses 
that make use of stability-of-references. Please make sure you do. It's 
sufficient to fix QToolBox (Page, iirc) and QDataWidgetMapper (WidgetMapper). The 
more the merrier, though.


Marc Mutz <marc.mutz at kdab.com> | Senior Software Engineer
KDAB (Deutschland) GmbH & Co.KG, a KDAB Group Company
Tel: +49-30-521325470
KDAB - The Qt Experts

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