QT UDP加入组播失败

51039869

imx6dl开发板，linux4.9+qt5.8环境，调用joinMulticastGroup返回false，打印的socket->error()是QAbstractSocket::UnknownSocketError。
以下是代码。有人知道返回false的原因吗?

   bool result = false;
   m_udpsocket_recive = new QUdpSocket(this);
   QHostAddress mcast_addr("224.0.0.17");
   result = m_udpsocket_recive->bind(QHostAddress::AnyIPv4,45454, QUdpSocket::ReuseAddressHint);
   qDebug()<<"Phone_Init1 result"<<result;
   qDebug()<<"Phone_Init1 "<<m_udpsocket_recive->error();
   qDebug()<<"Phone_Init1 "<<m_udpsocket_recive->state();
   result = m_udpsocket_recive->joinMulticastGroup(mcast_addr);
   qDebug()<<"Phone_Init result"<<result;
   qDebug()<<"Phone_Init "<<m_udpsocket_recive->error();
   qDebug()<<"Phone_Init "<<m_udpsocket_recive->state();
   connect(m_udpsocket_recive, SIGNAL(readyRead()),this, SLOT(RecvDateSlot()));

qianww001

你先打开makefile 看有可能包含qt4的库的