[Qt-interest] Using qSort with lists of QPointers

[Ellen Kestrel]

I'm trying to use qSort to sort a list of QPointers to a class (which
subclasses QObject).  There is a public lessThan function actually within
the class itself, and when I was sorting the list by hand I simply called it
from the class that manages the list.  Since I want to use qSort in the
list-managing class, I defined a member function in that class with only
this line of code:

bool ListManager::objPrecedes (QPointer<MyClass> c1, QPointer<MyClass> c2)
{
  return c1->comesBefore (c2);
}

and tried calling qSort as

qSort (list.begin (), list.end (), objPrecedes);

but this gives me a compiler error:

error: no matching function for call to ‘qSort(QList<QPointer<MyClass>
>::iterator, QList<QPointer<MyClass> >::iterator, <unresolved overloaded
function type>)’
/usr/include/qt4/QtCore/qalgorithms.h:184: note: candidates are: void
qSort(RandomAccessIterator, RandomAccessIterator, LessThan) [with
RandomAccessIterator = QList<QPointer<MyClass> >::iterator, LessThan = bool
(ListManager::*)(QPointer<MyClass>, QPointer<MyClass>)]

Can anyone tell me what I might be doing wrong, here?  I thought about
simply overloading the < operator and not passing the function as an
argument, but my guess is that since this is a list of pointers, it will
simply compare the values of the pointers rather than try to use < on the
objects they point to.

EK
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