Difference of slots and functions in Qt

Not with anything. Slots and functions (methods) are the same. For c ++ 11, you can connect signals with lambdas or with functions directly, bypassing the declaration of slots and using the macro SLOT .

Upd: For the slots, some meta information is generated - the name and hint for the slot call. This is where the difference ends and thanks to the moc programmer, this difference will not be visible :)

I will give an example of connecting a signal to the slot, function and method (works for C ++ 11 and Qt5):

This describes the most common header file:

 #include <QMainWindow> #include <QPushButton> #include <QDebug> class MainWindow : public QMainWindow { Q_OBJECT public: explicit MainWindow(QWidget *parent = 0); void doooooo(); public: QPushButton button; public slots: void foooooo(); void foooooo2(); }; 

And the most interesting will be in cpp. There I connect the signal to the slots, method and function:

 #include "mainwindow.h" void goooooo() { qDebug() << "goooooo"; } MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent) { setCentralWidget(&button); // Новая семантика коннектов: connect(&button, &QPushButton::clicked, this, &doooooo); connect(&button, &QPushButton::clicked, this, &foooooo); connect(&button, &QPushButton::clicked, this, &goooooo); connect(&button, &QPushButton::clicked, this, [] { qDebug() << "lambda"; }); // Старая: connect(&button, SIGNAL(clicked(bool)), this, SLOT(foooooo2())); // Слоты это функции, поэтому можно вручную вызывать их foooooo(); foooooo2(); qDebug() << ""; } void MainWindow::doooooo() { qDebug() << "doooooo"; } void MainWindow::foooooo() { qDebug() << "foooooo"; } void MainWindow::foooooo2() { qDebug() << "foooooo2"; } 

More information on new connect syntax can be found here.

And on lambda here