Pi4 управление портами ввода-вывода.

QFile exportFile("/sys/class/gpio/gpio19/export");
exportFile.open(QIODevice::WriteOnly);
exportFile.write("19");

QFile directionFile("/sys/class/gpio/gpio19/direction");
directionFile.open(QIODevice::WriteOnly);
directionFile.write("in");

QFile edgeFile("/sys/class/gpio/gpio19/edge");
edgeFile.open(QIODevice::WriteOnly);
edgeFile.write("body");

QFile file("/sys/class/gpio/gpio19/value");

QSocketNotifier notifier(file.handle(), QSocketNotifier::Read);
connect(&notifier, &QSocketNotifier::activated, this, &MyClass::interruptFired);