[Development] Changing qreal to a float

[João Abecasis]

Boudewijn Rempt wrote:
> Well, Qt is a library, a platform -- and that means that you cannot predict how and when classes and things like qreal will be used, and that if something is changed there, it _will_ mean a porting effort, potentially a big one. Heck, we haven't even really recovered from the previous porting from Qt3 to Qt4!

Hence my suggestion: Drop qreal entirely, don't deprecate it and don't try to figure out what it should mean. We realized it was a broken concept and it plays against the C++ language we depend on.

What's the porting effort for applications that use and depend on qreal?

Application developers have to decide exactly what qreal was supposed to mean for them and typedef it to what's appropriate. It's a one-line change. They can patch Qt's qglobal.h if they ship their version of Qt, or they can add the typedef in their own code.

Libraries that depend on Qt will have to analyze the issue and make their own decision: a) jump to double or float or b) provide their own AwesomeReal, if that makes sense in their context.

It's not even a surprise or unexpected outcome if we document the issue or make sure a meaningful error is generated upon use of qreal.

The bigger porting effort doesn't come from the disappearance of qreal itselft, but from changing Qt itself to not use it as users will no longer be able to assume QRectF and whatnot use double on their platform. And no one seems to be against that.

Cheers,


João