学步园

    QNetworkInterface  localInterface =localInterface.interfaceFromName("设备名称 例如 eth0");
         QString MAC =localInterface.hardwareAddress()/* "90:FB:A6:11:52:63"*/;
        int localNetmask = 0xFFFFFF00;
       int localIP ;
         for(int i =0; i < localInterface.addressEntries().size(); i ++)
         {
             if( !localInterface.addressEntries().at(i).ip().isNull() &&localInterface.addressEntries().at(i).ip().protocol()==QAbstractSocket::IPv4Protocol)
             {
                 localIP = localInterface.addressEntries().at(i).ip().toIPv4Address();
                 localNetmask =  localInterface.addressEntries().at(i).netmask().toIPv4Address();
                 break;
             }
         }

以上方法貌似某些情况下也不好使，可以试试下面的方法：

        QString localHostName=QHostInfo::localHostName();
        QHostInfo hostInfo=QHostInfo::fromName(localHostName);
        QList<QHostAddress>listAddress=hostInfo.addresses();

           for(int j = 0; j < listAddress.size(); j++)
           {
           
               if(!listAddress.at(j).isNull() && listAddress.at(j).protocol() ==  QAbstractSocket::IPv4Protocol
                  && listAddress.at(j) != QHostAddress::LocalHost)
               {
                   emit this->sendMsg(listAddress.at(j).toString());
                   break;
               }
           }
获取本机有效IP地址、掩码、网关、MAC地址，一直以来我都没找到有效方法，以前用MFC时也是这样，真无语了...

再或者：

    QList<QHostAddress>listAddress = QNetworkInterface::allAddresses();

     for(int j = 0; j < listAddress.size(); j++)

     {

            if(!listAddress.at(j).isNull() && listAddress.at(j).protocol() ==  QAbstractSocket::IPv4Protocol

               && listAddress.at(j) != QHostAddress::LocalHost)

            {

                localIPAddress = listAddress.at(j).toString();

                break;

            }

     }