Loading data in a thread

[Cruz]

I'm assuming that you are probably loading data from some file and want to show the user a "live" representation of the structure as it gets filled.

Precisely.

I don't understand though why are you so reluctant to use a mutex, it seems a perfect solution here. If you add a bit of smart logic around it, the final effect should be really good.

I was a little bit reluctant, because people say it slows things down. But mostly I wanted an explanation why it makes sense, because I didn't know that reading from the QList can trigger copying. The mutex is in place now and there is no noticable change in the performance. But now it bugs me that in the background the data structure gets copied thousands of times even though it's totally unnecessary.