qt_upd_socket_read.cpp

#include <QCoreApplication>
#include <QUdpSocket>
#include <QObject>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    QUdpSocket _s;
    _s.bind( QHostAddress::LocalHost, 9000 );

    QObject::connect( &_s, &QUdpSocket::readyRead, [&_s]()
    {
        QByteArray data {};

        while( _s.hasPendingDatagrams() )
        {
            auto size = _s.pendingDatagramSize();
            data.resize( size );
            _s.readDatagram( data.data(), size );
            data.trimmed();
            qDebug() << data << "size:" << size;
        }
    });

    return a.exec();
}