UDP communication using static library and test program

supratik123

I am trying to create a UDP communication using static library and test program using UDp protocol. I have taken a QScopedPointer of QUDPSocket class. I am resetting the data in my test program. Everything is working fine except I am facing some issues with the writedatagram function. I am not sure about the syntax of the writedatagram method . Below is my code snippet

m_UdpComm.reset(new QUdpSocket);
QString word="Hello UDP server";
QByteArray buffer;
buffer.resize(m_UdpComm.data()->pendingDatagramSize());
buffer=word.toUtf8();
m_UdpComm.data()->writeDatagram(buffer.data(),p_proConfig.p_ipAddress,p_proConfig.p_port);
qDebug()<<p_proConfig.p_ipAddress;
qDebug()<<p_proConfig.p_port;

The declarations:

struct ProAxeSEConfig
{
    //list of members of ProAxeSEConfig structure
    QString p_ipAddress;
    quint16 p_port;
};
ProAxeSEConfig p_proConfig;
ProAxeSE(ProAxeSEConfig p_proConfig);
QScopedPointer<QUdpSocket> m_UdpComm;

I am facing issues in the writedatagram statement

KroMignon

@supratik123 Hi @supratik123, before sending datagram with an UDP socket, you have to bind the socket to a local UDP port.

 m_UdpComm.reset(new QUdpSocket);
 m_UdpComm->bind(QHostAddress::LocalHost, 0); // use 0 to let TCP/IP stack select the first free UDP port

Please have a look at the Qt documentation: QUdpSocket Class

[Edit aha_1980: Fixed m_UdpComm.->bind]

supratik123

@KroMignon Hi KroMignon, I try to understand this, but since this is my client side and just want one side i.e half duplex connection, so do it matter to bind my client socket. I have used bind in my server side and it is working fine. Qt is giving me no matching function call for writeDatagram() error.

KroMignon

@supratik123 What do you want to know? If it is the last error use QUdpSocket::error() to get the error code or QUdpSocket::errorString() as it is describe in the help QUdpSocket::writeDatagram()

supratik123

@KroMignon Okay Thanks For the help.

Pablo J. Rogina

@supratik123 is your issue solved? if so please mark your post as such!. Thanks.