On Monday 30 November 2009 12:07:29 Uwe Rathmann wrote: > Olivier Goffart wrote: > > I would like to add that using a floating point type as a key of a QHash > > might be dangerous as there will be == comparison on floating point type, > > which might not work well due to rounding issue > > The Qwt code is completely uninterested in hashing (or sorting) of doubles. > It only uses a simple QList<double> to store doubles for its values.
QList does not need any qHash function. > > To my knowledge, Qt never had a qHash function for floating point types. > > I just verified it by grepping the diff between Qt 4.5 and Qt 4.6 > > For Qt <= 4.2 I had to add a dummy implementation of qHash<double> I guess you meant qHash(double) > to the Qwt headers. After reporting the bug to the TrollTech support the > problem was gone in Qt 4.3. Seems like this ( or a similar ) problem has > been reintroduced in Qt 4.6. Which problem are you talking about here? > > To my knowledge, Qt never had a qHash function for floating point types. > > I just verified it by grepping the diff between Qt 4.5 and Qt 4.6 > > I didn't check the QTL code, but I guess the code in qhash.h(875) is not > instantiated by the compiler in Qt 4.3 - Qt 4.5 for lists, that are never > sorted ? Sorry, I do not understand here. What is QTL? What are Lists that are not sorted, do you mean QSet<double>? Would be interesting to know what is instantiating that code. _______________________________________________ Qt4-preview-feedback mailing list [email protected] http://lists.trolltech.com/mailman/listinfo/qt4-preview-feedback
