QKeyEvent key() only returns value of first surrogate for characters in Supplementary Planes

#include<iostream>
#include<QApplication>
#include<QWidget>
#include<QKeyEvent>

struct App:QWidget{
	void keyPressEvent(QKeyEvent* event){
		std::cout<<"key 0x"<<std::hex<<event->key()<<", text ";
		char prev='[';
		for(QChar& c:event->text()){
			std::cout<<prev<<"0x"<<c.unicode();
			prev=' ';
		}
		if(prev=='[')std::cout<<'[';
		std::cout<<"]\n";
	}
};

int main(int argc,char** argv){
	QApplication app(argc,argv);
	App ex;
	ex.show();
	return app.exec();
}

xdotool type --window 87654321 --clearmodifiers $(printf '\U0001f3fc')

key 0xd83c, text [0xd83c 0xdffc]