I wonder if using the new Qt5 slot connection mechanism with lambdas increase the size of the generated code?
And if not, I assume its faster during runtime, than the old string lookup?
I wonder that myself, but hadn't time to check the binary increase. But I would say its faster than a string lockup.
Usually string lockup is fast enough though. I mean Quake used string lockup for instantly playing audio files back in the 90's.
I don't think it differs all that much in code execution. Maybe the code for the connect function is different, but the execution of the signal/slot will be the same, because in basic none has changed.