vs2012 c# and unix c server socket communication

i'm writing a client program in c# vs2012 and server on linux raspbian in c. They are in the same network and client connects to the serv alright. The issue is, when i send something from client to serv, the serv doesn't react. I don't know whether my problem lies in the client or in the server.

the server code:

#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>

#define PORTNUM 4510
#define MAXRCVLEN 255

void set_fifo(int *fifo1, int *fifo2)
{
    mkfifo("/tmp/fifo1", 0600); // 1 - Reading from serial
    mkfifo("/tmp/fifo2", 0600); // 2 - Writing to serial

    if((*fifo1 = open("/tmp/fifo1", O_RDONLY) < 0) || (*fifo2 = open("/tmp/fifo2", O_WRONLY) < 0))
    {
        error("ERROR opening FIFO\n");
        exit(1);
    }
}

int main(int argc, char *argv[])
{
    char msg[] = "Hello World !\n";
    char buffer[MAXRCVLEN];

    int fifo1, fifo2;
    set_fifo(&fifo1, &fifo2);

    int len = 0;
    struct sockaddr_in dest; /* socket info about the machine connecting to us */
    struct sockaddr_in serv; /* socket info about our server */
    int mysocket;            /* socket used to listen for incoming connections */
    socklen_t socksize = sizeof(struct sockaddr_in);

    memset(&serv, 0, sizeof(serv));           /* zero the struct before filling the fields */
    serv.sin_family = AF_INET;                /* set the type of connection to TCP/IP */
    serv.sin_addr.s_addr = htonl(INADDR_ANY); /* set our address to any interface */
    serv.sin_port = htons(PORTNUM);           /* set the server port number */    

    mysocket = socket(AF_INET, SOCK_STREAM, 0);

    /* bind serv information to mysocket */
    bind(mysocket, (struct sockaddr *)&serv, sizeof(struct sockaddr));

    /* start listening, allowing a queue of up to 1 pending connection */
    listen(mysocket, 1);
    int consocket = accept(mysocket, (struct sockaddr *)&dest, &socksize);


    while(consocket)
    {
        printf("Incoming connection from %s\n", inet_ntoa(dest.sin_addr));

        recv(mysocket, buffer, MAXRCVLEN, 0)
        buffer[MAXRCVLEN] = '\0';
        printf("Message: %s", buffer);

        //send(consocket, msg, strlen(msg), 0); 
        consocket = accept(mysocket, (struct sockaddr *)&dest, &socksize);
    }

    close(consocket);
    close(mysocket);
    return EXIT_SUCCESS;
}

I'm properly getting the "Incoming connection from" message after client connects. Client send method:

private void sendButton_Click(object sender, EventArgs e)
{
    try
    {
        string theMessageToSend = "Hello!";
        byte[] msg = Encoding.ASCII.GetBytes(theMessageToSend);
        senderSock.Send(msg);
    }
    catch (Exception exc) { MessageBox.Show(exc.ToString()); }
}

The try-catch doesn't throw anything.

And the method i use in client to connect to serv:

private void button1_Click(object sender, EventArgs e)
{
    connectButton.Text = "Connecting...";
    try
    {
        SocketPermission permission = new SocketPermission(
            NetworkAccess.Connect,    // Connection permission 
            TransportType.Tcp,        // Defines transport types 
            "",                       // Gets the IP addresses 
            SocketPermission.AllPorts // All ports 
            );
        permission.Demand();

        IPAddress ipAddr = IPAddress.Parse(ipInput.Text);
        int portNr = Convert.ToInt32(portTextBox.Text);
        IPEndPoint ipEndPoint = new IPEndPoint(ipAddr, portNr);

        // Create one Socket object to setup Tcp connection 
        senderSock = new Socket(
            ipAddr.AddressFamily,// Specifies the addressing scheme 
            SocketType.Stream,   // The type of socket  
            ProtocolType.Tcp     // Specifies the protocols  
            );

        senderSock.NoDelay = false;   // Using the Nagle algorithm 

        // Establishes a connection to a remote host 
        senderSock.Connect(ipEndPoint);
        tbStatus.Text = "Socket connected to " + senderSock.RemoteEndPoint.ToString();

        connectButton.Enabled = false;
        connectButton.Text = "Connected";
        mainStart.Enabled = true;
    }
    catch (Exception exc) 
    { 
        MessageBox.Show(exc.ToString());
        connectButton.Text = "Connect";
    }
}