When writing Qt applications there are a few pointers that you can keep in mind to avoid adding
unneeded overhead to your code.
-----Evaluate if you really need to inherit QObject. Sometimes you do it just out of habit.
-----Avoid the Q_OBJECT macro if you can. You need the macro if you add new signals, slots or
properties, or if you use the qobject_cast function with your class.
-----If performance counts, use custom events to pass information between threads instead of
signals and slots.
-----Try to avoid copying data by adding implicit sharing to your complex data carrying classes.
See more at
http://doc.trolltech.com/4.5/shared.html .
从Ensuring Maximum Performance with Qt上看到的。
与一般的说法还真有点不一样的哦。
