[Development] important: upcoming rename of _qpa.h to _p.h

[lars.knoll at nokia.com]

On 4/17/12 9:58 PM, "ext Thiago Macieira" <thiago.macieira at intel.com>
wrote:

>On terça-feira, 17 de abril de 2012 15.37.35,
>marius.storm-olsen at nokia.com
>wrote:
>> Yes, it does.
>> And for the case of QPA, we have said that we don't want to promise BC,
>>but
>> we haven't said that we will go around breaking SC for every patch
>>release.
>> (And we shouldn't, since SC breakage uses quite a bit of resources on
>>all
>> parties, so avoid them if you can.)
>
>There was no SC promise either. We shouldn't go breaking it completely in
>5.1 
>or later, but I also see no reason why we couldn't do it if there were
>the 
>need. Also, SC but not BIC changes are very limited -- such as adding
>non-pure 
>virtual functions (which we can do) and adding members to classes (which
>we 
>won't do). Renaming functions or classes or removing them also break BC.
>
>Suppose we detect that the entire keyboard interface is broken and needs
>an 
>overhaul, removing a method. Plugins will need to adapt, period.
>
>> Like some others, I would prefer it to remain in non-private headers,
>>while
>> mark the QPA API with non-BC promise. IMO, in Qt 5.1 we should be able
>>to
>> promise BC on the QPA APIs too.
>
>I don't like the new category of headers -- it sets a precedent. What's
>more, 
>when we *do* offer SC and BC, I see no reason to have "_qpa" either. It's
>API 
>anyway.
>
>As for whether we can promise source and/or binary compatibility in 5.1,
>time 
>will tell. I hope we can do it, I won't shed a tear if we can't.

Still the QPA headers are sort of a different beast from private headers.
While I don't want to promise anything on them yet (I think we might want
to keep SC and BC for them in patch level releases), they are supposed to
be used by third parties and supported. Our private headers are not
supported.

So in an ideal world it wouldn't be a private, but something that you get
(and only get) when you add something like QT += qpa to your project.

Cheers,
Lars