[Development] QMetaTypeId and QMetaTypeId2

Stephen Kelly stephen.kelly at kdab.com
Thu Feb 9 12:39:54 CET 2012


On Thursday, February 09, 2012 10:07:16 Jedrzej Nowacki wrote:
> Hi,
> 
>   Does anybody know why we have separation between QMetaTypeId and
> QMetaTypeId2 classes?
> 
>   QMetaTypeId2 delegates all operations to QMetaTypeId by default and
> qMetaTypeId() function is calling QMetaTypeId2. To make it more complex
> Q_DECLARE_METATYPE is specializing QMetaTypeId but
> Q_DECLARE_BUILTIN_METATYPE is specializing QMetTypeId2. From an user
> perspective it is not visible, but it makes implementation complex.
> 
>   Can I merge QMetaTypeId and QMetaTypeId2?

I always thought they were split so that Qt could add new built-in metatypes 
without breaking user code.

Eg, if you merge them, any user code doing:

Q_DECLARE_METATYPE(QModelIndex)

will no longer compile until that line is removed (It is a built-in metatype 
now).

Thanks,

-- 
Stephen Kelly <stephen.kelly at kdab.com> | Software Engineer
KDAB (Deutschland) GmbH & Co.KG, a KDAB Group Company
www.kdab.com || Germany +49-30-521325470 || Sweden (HQ) +46-563-540090
KDAB - Qt Experts - Platform-Independent Software Solutions
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