Efficiency of Qt Signals and Slots

Question

I was browsing the methods inside of QMainWindow and noticed that some parts (such as resizeEvent and winEvent) are not implemented as signals but rather you have to inherit this class to be able to override them.

My question is, how efficient are signals and slots and would it be possible to implement these types of functions as signals from which other classes can subscribe to. For instance, inside of a high performance game engine.

Answer 1

From what I recall, Trolltech stated that a signal/slot call is about 10 times slower than a virtual call. You should be able to easily process tens, if not hundreds of thousands signals per second.