Simulink link by tcpip with C++ application

I am tryng to build a link between my simulink model or just an m file and my C++ application but I'm having an issue. I don't really understand how matlab receives the data, and for simulink in which form should I send the data to the block? I would like to send coordinates like xyz to matlab and with matlab scatter3 the stream of coordinates in real time. Is it possible ?

Here is the C++ extract code : (sorry comments are in french)

                /* Démarrage du listage (mode server) */
                sock_err = listen(sock, 5);
                printf("Listage du port %d...\n", PORT);

                /* Si la socket fonctionne */
                if(sock_err != SOCKET_ERROR)
                {
                    /* Attente pendant laquelle le client se connecte */
                    printf("Patientez pendant que le client se connecte sur le port %d...\n", PORT); 

                    csock = accept(sock, (SOCKADDR*)&csin, &recsize);
                    printf("Un client se connecte avec la socket %d de %s:%d\n", csock, inet_ntoa(csin.sin_addr), htons(csin.sin_port));
                   // double buff = 25;

mxArray *datasend;
datasend = mxCreateDoubleMatrix(1, 1, mxREAL);
mlfPrintmatrix(datasend);

                    sock_err = send(csock, T, 3*sizeof(double), 0);

                    if(sock_err != SOCKET_ERROR)
                        printf("Send : %s\n", buffer[0]);
//printf("send : [10 20 30]");
                    else
                        printf("Erreur de transmission\n");

                    /* Il ne faut pas oublier de fermer la connexion (fermée dans les deux sens) */
                    shutdown(csock, 2);
                }

Simulink errors:

Error evaluating registered method 'Outputs' of M-S-Function 'stcpiprb' in 'trajectory2/TCP//IP Receive'. The specified amount of data was not returned within the Timeout period.
Please ensure that data is being sent to the specified port or specify a greater timeout value.

The specified amount of data was not returned within the Timeout period.
Please ensure that data is being sent to the specified port or specify a greater timeout value.

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# Finite State Machines
#
# Stateflow Version 7.1 (R2009a) dated Jul 17 2009, 00:35:51
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#


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---

I can't see creating socket and binding to it in your C code. Are you sure that you're binding on 127.0.0.1 and port 80? Are you sure that there's no some apache running on the server on port 80?

http://www.linuxhowtos.org/C_C++/socket.htm

Also:

sock_err = send(csock, T, 3*sizeof(double), 0);

I don't also see T in your code, which is probably not the issue, but it doesn't seem to be the datasend pointer to mxArray.