In this chapter, we created a cross-platform SysInfo application. We covered the singleton and the strategy pattern to have a neat code organization with platform-specific code. You learned to use the Qt Charts module to display system information in real time. Finally, we took a deep dive into the qmake command to see how Qt implements the signal/slot mechanism, and to see what is hidden behind Qt-specific keywords (emit, signals, and slots).
By now, you should have a clear picture of how Qt works and how you can tackle a cross-platform application. In the next chapter, we will look at how you can split a bigger project in order to keep your sanity as a maintainer. We will study a fundamental pattern in Qt--the Model/View--and discover how to use a database with Qt.