Скачать или смотреть Understanding qAsConst / std::as_const

Do you remember to add qAsConst around your Qt containers when you iterate them? If not, there is a real risk that you are paying a price tag for them detaching just as you are about to start.

In  this episode, Jesper has a chat with his coworker Peppe to better understand what qAsConst does, why and when it is needed, and how to work around issues with iterating containers that are the result of calling a function.

0:00 Introduction
0:57 implicit shared
3:16 the container might be copied
3:40 what does the for loop expands to?
5:04 What is the cure?
5:35 Solution: create a const copy of the contrainer.
7:00 Solution: Make the method const
7:40 Colution: use qAsConst
9:05 qAsConst and rvalues
10:30 But but but - nobody else has access...
12:45 Returning a const
15:05 Standard containers
15:46 a C++20 solution
17:04 Summary

The example code showcased in this video is available here: https://github.com/KDAB/kdabtv/tree/m...

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About the host:
The video is presented by Jesper Pedersen, who started with Qt back when Qt was widgets only and the version was 1.44, which gives him 21 years of experience with Qt. Since 2000 he has taught almost 100 Qt classes, ranging from Qt Widgets to QML. Heck, Jesper even taught a few classes on QTopia Core — Trolltech's initial attempt at creating a phone stack. Today Jesper holds a fancy business title, but that doesn't prevent him from coding both in his job and in his spare time.

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