Game Programming using Qt 5 Beginner's Guide - Second Edition

Creating signals and slots

If you create a QObject subclass (or a QWidget subclass, as QWidget inherits QObject), you can mark a method of this class as a signal or a slot. If the parent class had any signals or non-private slots, your class will also inherit them.

In order for signals and slots to work properly, the class declaration must contain the Q_OBJECT macro in a private section of its definition (Qt Creator has generated it for us). When the project is built, a special tool called Meta-Object Compiler (moc) will examine the class's header and generate some extra code necessary for signals and slots to work properly.

Keep in mind that moc and all other Qt build tools do not edit the project files. Your C++ files are passed to the ...