C / C++ / MFC

SOCKET CMultycast_serverDlg::CreateTCPServerSocket(int PortNumber)
{
	// this function create a socket for each port
	int Socket = 0;                  /* socket to create */
    struct sockaddr_in echoServAddr; /* Local address    */
    int bind_res;
    WSADATA wsaData;
	CString string;
	unsigned long argp = 1;

    if(WSAStartup(0x202,&wsaData) == SOCKET_ERROR)
	{
		AfxMessageBox(" Error :  WSAStartup() has failed   ");
		return -1;
	}

    /*==== Create socket for incoming connections ====*/
	Socket = socket(PF_INET,SOCK_STREAM,IPPROTO_TCP);
	if(Socket == INVALID_SOCKET)
	{
		string.Format("  Unable to create socket for port #%d  ",PortNumber);
		AfxMessageBox(string);
		return -1;
	}

 	ioctlsocket(Socket , FIONBIO , &argp);
   /*==== Construct local address structure ====*/
	memset(&echoServAddr,0,sizeof(echoServAddr));           //zero out structure
	echoServAddr.sin_family=AF_INET;                        //internet address family
	echoServAddr.sin_addr.S_un.S_addr=htonl(INADDR_ANY);    //any incoming inteface
	echoServAddr.sin_port=htons(PortNumber);                //local address
    
    /*==== bind to the local address ====*/
	bind_res = bind(Socket,(struct sockaddr*)&echoServAddr,sizeof(echoServAddr));
	if(bind_res == SOCKET_ERROR)
	{
		string.Format("  Unable to create bind to local address for port #%d  ",PortNumber);
		AfxMessageBox(string);
		return -1;
	}

	/*==== mark the socket so it will listen for incoming connections ====*/
	if(listen(Socket,MAXPENDING) == SOCKET_ERROR)
	{
		string.Format("  Unable to listen to socket in port #%d  ",PortNumber);
		AfxMessageBox(string);
		return -1;
	}

	return Socket;
}