Qt5 switching qreal from float to double on arm*

[Scott Kitterman]

"Lisandro Damián Nicanor Pérez Meyer" <perezmeyer at gmail.com> wrote:
>Note: only for pkg-kde-talk.
>
>On Saturday 02 November 2013 15:29:05 Lisandro Damián Nicanor Pérez
>Meyer 
>wrote:
>> Hi! Starting from Qt 5.2.0 (most probably from rc1 and definitely not
>from
>> beta1 currently in experimental) Qt5 will switch qreal from float to
>double
>> on arm*.
>> 
>> We have the option to keep some archs in float by passing a
>compilation
>> parameter. I've done so for armel and sh4, so only armhf will switch
>to
>> double.
>> 
>> Of course we are still on time to discuss this, and this is the
>reason of
>> this mail. What do you think WRT the above changes?
>> 
>> On the other hand, if the above change is kept, symbols for Qt5 on
>armhf
>> managed with pkg-kde-tools' symbolshelper will need an explicit
>double for
>> armhf instead of using qreal's subst. This is because on Qt4 qreal
>will be
>> kept as float.
>
>There's still the chance of doing **quite a bit** of work and
>backporting the 
>changes to Qt4 and make qreal a double on armhf too. But this means a
>**big** 
>transition for armhf would be needed, but on the other hand
>pkg-kde-tools' 
>symbolshelper could be changed to properly manage Qt4 and Qt5.
>
>I want to be clear: this last option could mean *lots* of work and I
>would 
>definitely *not* go ahead with it without a patch to Qt4 ACKed by
>upstream and 
>the rest of Qt/KDE-team.
>
>But I think at least should be considered and team approved/discarded.
>
>Kinds regards, Lisandro.

Doesn't this break binary compatibility? Did you discuss this with upstream already? 

Scott K