On 08/01/2013 11:49 PM, Orion Poplawski wrote:
http://doc.qt.digia.com/4.6/qtglobal.html#qreal-typedef
typedef qreal
Typedef for double on all platforms except for those using CPUs with ARM
architectures. On ARM-based platforms, qreal is a typedef for float for
performance reasons.
This still seems to be the case for 4.8 as well.
This lead to the following compile error on arm in kst:
/builddir/build/BUILD/kst-2.0.7/src/libkstapp/plotrenderitem.cpp:561:33:
error: no matching function for call to 'qMin(double&, qreal)'
y = qMin(y, plotItem()->yMax());
^
If there is scientific type codes using qreal this might lead to some
precision issues as well.
Yes, we've had to patch quite a few packages to fix/workaround
qreal!=double assumptions in code.
Is double really that much slower on arm?
Good question for
https://lists.fedoraproject.org/mailman/listinfo/arm
(but, I assume the qt docs aren't lying and the answer is yes)
-- rex